initial commit

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -0,0 +1,38 @@
+name: "Bug report"
+description: Report an issue or possible bug
+title: "Bug report: "
+labels: ["bug"]
+assignees: []
+body:
+  - type: markdown
+    attributes:
+      value: Thank you for taking the time to file a bug report! Please fill out this form as completely as possible.
+  - type: input
+    attributes:
+      label: Operating System
+      placeholder: Mac, Windows, Linux
+    validations:
+      required: true
+  - type: input
+    attributes:
+      label: OPENRNDR version
+    validations:
+      required: true
+  - type: input
+    attributes:
+      label: ORX version
+    validations:
+      required: true
+  - type: input
+    attributes:
+      label: Java version (if applicable)
+  - type: textarea
+    attributes:
+      label: Describe the bug
+      description: A clear and concise description of what the bug is, optionally including a screenshot.
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: Steps to reproduce the bug
+      description: Describe the steps taken or paste/link a minimal code example that we can reproduce ourselves.

.github/ISSUE_TEMPLATE/feature_request.yml

@@ -0,0 +1,30 @@
+name: "Feature request"
+description: "Suggest an idea or general improvement."
+title: "Feature request: "
+labels: ["enhancement"]
+assignees: []
+body:
+  - type: markdown
+    attributes:
+      value: Thanks for taking the time to suggest a new feature! Please fill out this form as completely as possible.
+  - type: textarea
+    attributes:
+      label: Motivation
+      description: |
+        Description of what the problem is and what the desired solution would be.
+
+        **Include links to relevant issues or discussions, if there are any.**
+      placeholder: I want to be able to 
+    validations:
+      required: true
+  - type: dropdown
+    attributes:
+      label: Help make it happen!
+      description: "Feature requests with contributing authors are much more likely to get done!"
+      multiple: false
+      options:
+        - I am not willing to submit a PR to implement this change.
+        - I am willing to submit a PR to implement this change, but would need some guidance.
+        - I am willing to submit a PR to implement this change.
+    validations:
+      required: true

.github/workflows/build.yml

@@ -0,0 +1,53 @@
+name: Build
+on:
+  # Trigger the workflow on any pull request
+  pull_request:
+
+concurrency:
+  group: ${{ github.ref }}
+  cancel-in-progress: true
+
+defaults:
+  run:
+    working-directory: ./orx
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout current repository
+        uses: actions/checkout@v4
+        with:
+          path: ./orx
+
+      - name: Checkout OPENRNDR repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          repository: openrndr/openrndr
+          path: ./openrndr
+          ref: master
+
+      - name: Test glxinfo
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y mesa-utils xvfb
+          xvfb-run glxinfo
+
+      - uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: 21
+
+      - name: Setup Gradle
+        uses: gradle/actions/setup-gradle@v4
+
+      - name: Build OPENRNDR
+        working-directory: ./openrndr
+        run: ./gradlew publishToMavenLocal snapshot
+
+      - name: Build ORX
+        run: ./gradlew build
+
+      - name: Collect screenshots without errors
+        run: xvfb-run ./gradlew collectScreenshots

.github/workflows/generate-screenshots.yml

@@ -0,0 +1,69 @@
+name: Build and generate screenshots
+on:
+  push:
+    branches: [ master ]
+
+defaults:
+  run:
+    working-directory: ./orx
+
+jobs:
+  generate_screenshots:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout current repository
+        uses: actions/checkout@v4
+        with:
+          path: ./orx
+
+      - name: Checkout OPENRNDR repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          repository: openrndr/openrndr
+          path: ./openrndr
+          ref: master
+
+      - name: Test glxinfo
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y mesa-utils xvfb
+          xvfb-run glxinfo
+
+      - uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: 21
+      
+      - name: Setup Gradle
+        uses: gradle/actions/setup-gradle@v4
+
+      - name: Build OPENRNDR
+        working-directory: ./openrndr
+        run: ./gradlew publishToMavenLocal snapshot
+
+      - name: Build ORX
+        run: ./gradlew build
+
+      - name: Collect screenshots
+        run: xvfb-run ./gradlew collectScreenshots
+
+      - name: Build main readme
+        run: xvfb-run ./gradlew buildMainReadme
+
+      - name: Prepare media branch
+        run: |
+          git config --global user.email "actions@openrndr.org"
+          git config --global user.name "OPENRNDR Actions"
+          git reset HEAD -- .
+          (git add README.md && git commit -m "add auto-generated README" && git push origin master) || true
+          (git add [a-z-]*/README.md && git commit -m "add demos to README.md" && git push origin master) || true
+          (git add orx-jvm/[a-z-]*/README.md && git commit -m "add orx-jvm demos to README.md" && git push origin master) || true
+          git checkout --orphan media
+          git reset HEAD -- .
+          git add [a-z-]*/images/*.png
+          cd orx-jvm
+          git add [a-z-]*/images/*.png
+          cd ..
+          git commit -m "add auto-generated media"
+          git push -f origin media

.github/workflows/pick-me.yml

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+name: Pick me issue assignment
+
+on:
+  issue_comment:
+    types: [created, edited]
+jobs:
+  auto-assign:
+    runs-on: ubuntu-latest
+    steps:
+      - name: 'Auto-assign issue'
+        uses: edwinRNDR/pick-me@v0.3
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/release-apidocs.yml

@@ -0,0 +1,65 @@
+name: Release API docs
+on:
+  push:
+    branches: [ master ]
+
+defaults:
+  run:
+    working-directory: ./orx
+
+jobs:
+  release_apidocs:
+    if: github.repository == 'openrndr/orx'
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout current repository
+        uses: actions/checkout@v4
+        with:
+          path: ./orx
+          fetch-depth: 0
+
+      - name: Checkout OPENRNDR repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          repository: openrndr/openrndr
+          path: ./openrndr
+          ref: master
+
+      - name: Test glxinfo
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y mesa-utils xvfb
+          xvfb-run glxinfo
+
+      - uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: 21
+
+      - name: Setup Gradle
+        uses: gradle/actions/setup-gradle@v4
+
+      - name: Build OPENRNDR
+        working-directory: ./openrndr
+        run: ./gradlew publishToMavenLocal snapshot
+
+      - name: Build apidocs
+        run: ./gradlew :dokkaGenerate -Dorg.gradle.jvmargs=-Xmx1536M
+
+      - name: Publish to gh-pages
+        run: |
+          git worktree add --detach docs-temp
+          cd docs-temp
+          git checkout --orphan gh-pages
+          git reset HEAD -- .
+          git clean -df
+          mv ../build/dokka/html/* .
+          cp ../dokka/styles/* styles/
+          echo orx.openrndr.org > CNAME
+          git status
+          git config --global user.email "actions@openrndr.org"
+          git config --global user.name "OPENRNDR Actions"
+          git add . 
+          git commit -m "Add automatically generated API docs"
+          git push origin gh-pages --force

.github/workflows/release-candidate-to-maven-central.yml

@@ -0,0 +1,25 @@
+name: Release candidate to Maven Central
+on:
+  push:
+    tags:
+      - v[0-9].[0-9]+.[0-9]+-rc.[0-9]+
+jobs:
+  release_candidate_to_maven_central:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: 21
+      - name: Build ORX
+        run: ./gradlew -Prelease.useLastTag=true build
+      - name: Decode
+        run: |
+          echo "${{secrets.SIGNING_SECRET_KEY_RING_FILE}}" > ~/.gradle/secring.gpg.b64
+          base64 -d ~/.gradle/secring.gpg.b64 > ~/.gradle/secring.gpg
+      - name: Publish
+        run: ./gradlew publishAggregationToCentralPortal -Prelease.useLastTag=true -Psigning.keyId=${{secrets.SIGNING_KEY_ID}} -Psigning.password=openrndr -Psigning.secretKeyRingFile=$(echo ~/.gradle/secring.gpg)
+        env:
+          OSSRH_USERNAME: ${{secrets.OSSRH_USERNAME}}
+          OSSRH_PASSWORD: ${{secrets.OSSRH_PASSWORD}}

.github/workflows/release-to-maven-central.yml

@@ -0,0 +1,27 @@
+name: Release to Maven Central
+on:
+  push:
+    tags:
+      - v[0-9].[0-9]+.[0-9]+
+      - v[0-9].[0-9]+.[0-9]+-alpha[0-9]+
+      - v[0-9].[0-9]+.[0-9]+-beta[0-9]+
+jobs:
+  release_to_maven_central:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: 21
+      - name: Build ORX
+        run: ./gradlew -Prelease.useLastTag=true build
+      - name: Decode
+        run: |
+          echo "${{secrets.SIGNING_SECRET_KEY_RING_FILE}}" > ~/.gradle/secring.gpg.b64
+          base64 -d ~/.gradle/secring.gpg.b64 > ~/.gradle/secring.gpg
+      - name: Publish
+        run: ./gradlew publishAggregationToCentralPortal -Prelease.useLastTag=true -Psigning.keyId=${{secrets.SIGNING_KEY_ID}} -Psigning.password=openrndr -Psigning.secretKeyRingFile=$(echo ~/.gradle/secring.gpg)
+        env:
+          OSSRH_USERNAME: ${{secrets.OSSRH_USERNAME}}
+          OSSRH_PASSWORD: ${{secrets.OSSRH_PASSWORD}}

.gitignore

@@ -0,0 +1,11 @@
+*.iml
+.gradle
+/local.properties
+/.idea
+.DS_Store
+/build
+/captures
+.externalNativeBuild
+.cxx
+local.properties
+/.kotlin

android/.gitignore

@@ -0,0 +1 @@
+/build

android/build.gradle.kts

@@ -0,0 +1,62 @@
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+
+plugins {
+    alias(libs.plugins.android.application)
+    alias(libs.plugins.kotlin.android)
+}
+
+android {
+    namespace = "com.icegps.geotools"
+    compileSdk {
+        version = release(36)
+    }
+
+    defaultConfig {
+        applicationId = "com.icegps.geotools"
+        minSdk = 28
+        targetSdk = 36
+        versionCode = 1
+        versionName = "1.0"
+
+        testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
+    }
+
+    buildTypes {
+        release {
+            isMinifyEnabled = false
+            proguardFiles(
+                getDefaultProguardFile("proguard-android-optimize.txt"),
+                "proguard-rules.pro"
+            )
+        }
+    }
+    buildFeatures {
+        viewBinding = true
+    }
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_17
+        targetCompatibility = JavaVersion.VERSION_17
+    }
+}
+
+kotlin {
+    compilerOptions.jvmTarget = JvmTarget.JVM_17
+}
+
+dependencies {
+    implementation(libs.core.ktx)
+    implementation(libs.androidx.appcompat)
+    implementation(libs.material)
+    implementation(libs.androidx.activity)
+    implementation(libs.androidx.constraintlayout)
+    implementation(libs.mapbox.maps)
+    implementation(project(":math"))
+    implementation(libs.androidx.lifecycle.runtime.ktx)
+    implementation(project(":icegps-common"))
+    implementation(project(":icegps-shared"))
+    implementation(project(":icegps-triangulation"))
+
+    testImplementation(libs.junit)
+    androidTestImplementation(libs.ext.junit)
+    androidTestImplementation(libs.androidx.espresso.core)
+}

android/proguard-rules.pro

@@ -0,0 +1,21 @@
+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile

android/src/androidTest/java/com/icegps/geotools/ExampleInstrumentedTest.kt

@@ -0,0 +1,24 @@
+package com.icegps.geotools
+
+import androidx.test.platform.app.InstrumentationRegistry
+import androidx.test.ext.junit.runners.AndroidJUnit4
+
+import org.junit.Test
+import org.junit.runner.RunWith
+
+import org.junit.Assert.*
+
+/**
+ * Instrumented test, which will execute on an Android device.
+ *
+ * See [testing documentation](http://d.android.com/tools/testing).
+ */
+@RunWith(AndroidJUnit4::class)
+class ExampleInstrumentedTest {
+    @Test
+    fun useAppContext() {
+        // Context of the app under test.
+        val appContext = InstrumentationRegistry.getInstrumentation().targetContext
+        assertEquals("com.icegps.geotools", appContext.packageName)
+    }
+}

android/src/main/AndroidManifest.xml

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+    <!-- Include this permission to grab user's general location -->
+    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
+    <!-- Include only if your app benefits from precise location access. -->
+    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
+    <application
+        android:allowBackup="true"
+        android:icon="@mipmap/ic_launcher"
+        android:label="@string/app_name"
+        android:roundIcon="@mipmap/ic_launcher_round"
+        android:supportsRtl="true"
+        android:theme="@style/Theme.Orx">
+        <activity
+            android:name=".MainActivity"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+
+</manifest>

android/src/main/java/com/icegps/geotools/ContoursManager.kt

@@ -0,0 +1,427 @@
+package com.icegps.geotools
+
+import ColorBrewer2Type
+import android.content.Context
+import android.util.Log
+import colorBrewer2Palettes
+import com.icegps.math.geometry.Rectangle
+import com.icegps.math.geometry.Vector2D
+import com.icegps.math.geometry.Vector3D
+import com.icegps.geotools.catmullrom.CatmullRomChain2
+import com.icegps.geotools.ktx.area
+import com.icegps.geotools.ktx.toColorInt
+import com.icegps.geotools.ktx.toMapboxPoint
+import com.icegps.geotools.ktx.toast
+import com.icegps.geotools.marchingsquares.ShapeContour
+import com.icegps.geotools.marchingsquares.findContours
+import com.icegps.shared.ktx.TAG
+import com.icegps.triangulation.DelaunayTriangulation
+import com.icegps.triangulation.Triangle
+import com.mapbox.geojson.Feature
+import com.mapbox.geojson.FeatureCollection
+import com.mapbox.geojson.LineString
+import com.mapbox.geojson.Polygon
+import com.mapbox.maps.MapView
+import com.mapbox.maps.Style
+import com.mapbox.maps.extension.style.expressions.generated.Expression
+import com.mapbox.maps.extension.style.layers.addLayer
+import com.mapbox.maps.extension.style.layers.generated.fillLayer
+import com.mapbox.maps.extension.style.layers.generated.lineLayer
+import com.mapbox.maps.extension.style.layers.properties.generated.LineCap
+import com.mapbox.maps.extension.style.layers.properties.generated.LineJoin
+import com.mapbox.maps.extension.style.sources.addSource
+import com.mapbox.maps.extension.style.sources.generated.geoJsonSource
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.async
+import kotlinx.coroutines.awaitAll
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+import kotlin.math.max
+
+class ContoursManager(
+    private val context: Context,
+    private val mapView: MapView,
+    private val scope: CoroutineScope
+) {
+    private val sourceId: String = "contours-source-id-10"
+    private val layerId: String = "contours-layer-id-10"
+    private val fillSourceId: String = "contours-fill-source-id-10"
+    private val fillLayerId: String = "contours-fill-layer-id-10"
+    private val gridSourceId: String = "grid-polygon-source-id"
+    private val gridLayerId: String = "grid-polygon-layer-id"
+
+    private var contourSize: Int = 6
+    private var heightRange: ClosedFloatingPointRange<Double> = 0.0..100.0
+    private var cellSize: Double? = 10.0
+    val simplePalette = SimplePalette(
+        range = 0.0..100.0
+    )
+
+    private var colors = colorBrewer2Palettes(
+        numberOfColors = contourSize,
+        paletteType = ColorBrewer2Type.Any
+    ).first().colors.reversed()
+
+    private var points: List<Vector3D> = emptyList()
+
+    private val polylineManager = PolylineManager(mapView)
+
+    fun updateContourSize(contourSize: Int) {
+        this.contourSize = contourSize
+        colors = colorBrewer2Palettes(
+            numberOfColors = contourSize,
+            paletteType = ColorBrewer2Type.Any
+        ).first().colors.reversed()
+    }
+
+    fun updateCellSize(value: Double) {
+        cellSize = value
+    }
+
+    fun updatePoints(
+        points: List<Vector3D>,
+    ) {
+        this.points = points
+    }
+
+    fun updateHeightRange(
+        heightRange: ClosedFloatingPointRange<Double>? = null
+    ) {
+        if (heightRange == null) {
+            if (points.isEmpty()) {
+                return
+            }
+            val height = points.map { it.z }
+            val range = height.min()..height.max()
+            this.heightRange = range
+            simplePalette.setRange(range)
+        } else {
+            this.heightRange = heightRange
+            simplePalette.setRange(heightRange)
+        }
+    }
+
+    private var isGridVisible: Boolean = true
+    private var _gridModel = MutableStateFlow<GridModel?>(null)
+    val gridModel = _gridModel.asStateFlow()
+
+    fun setGridVisible(visible: Boolean) {
+        if (visible != isGridVisible) {
+            isGridVisible = visible
+            if (visible) {
+                _gridModel.value?.let { gridModel ->
+                    mapView.displayGridModel(
+                        grid = gridModel,
+                        sourceId = gridSourceId,
+                        layerId = gridLayerId,
+                        palette = simplePalette::palette
+                    )
+                }
+            } else {
+                mapView.mapboxMap.getStyle { style ->
+                    try {
+                        style.removeStyleLayer(gridLayerId)
+                    } catch (_: Exception) {
+                    }
+
+                    if (style.styleSourceExists(gridSourceId)) {
+                        style.removeStyleSource(gridSourceId)
+                    }
+                }
+            }
+        }
+    }
+
+    private var triangles: List<Triangle> = listOf()
+    private var isTriangleVisible: Boolean = true
+
+    fun setTriangleVisible(visible: Boolean) {
+        if (visible != isTriangleVisible) {
+            isTriangleVisible = visible
+            if (visible) {
+                polylineManager.update(
+                    triangles.map {
+                        listOf(it.x1, it.x2, it.x3)
+                            .map { Vector3D(it.x, it.y, it.z) }
+                    }
+                )
+            } else {
+                polylineManager.clearContours()
+            }
+        }
+    }
+
+    private var job: Job? = null
+
+    fun refresh() {
+        val points = points
+        if (points.size <= 3) {
+            context.toast("points size ${points.size}")
+            return
+        }
+        job?.cancel()
+        scope.launch {
+            mapView.mapboxMap.getStyle { style ->
+                val step = heightRange.endInclusive / contourSize
+                val zip = (0..contourSize).map { index ->
+                    heightRange.start + index * step
+                }.zipWithNext { a, b -> a..b }
+                val area = points.area
+                val triangulation = DelaunayTriangulation(points)
+                val triangles = triangulation.triangles()
+                val cellSize: Double = if (cellSize == null || cellSize!! < 0.1) {
+                    (max(triangulation.points.area.width, triangulation.points.area.height) / 50)
+                } else {
+                    cellSize!!
+                }
+                scope.launch {
+                    val gridModel = triangulationToGrid(
+                        delaunator = triangulation,
+                        cellSize = cellSize,
+                    )
+                    this@ContoursManager._gridModel.value = gridModel
+                    if (isGridVisible) mapView.displayGridModel(
+                        grid = gridModel,
+                        sourceId = gridSourceId,
+                        layerId = gridLayerId,
+                        palette = simplePalette::palette
+                    )
+                }
+                job = scope.launch(Dispatchers.Default) {
+                    val lineFeatures = mutableListOf<List<Feature>>()
+                    val features = zip.mapIndexed { index, range ->
+                        async {
+                            val contours = findContours(
+                                triangles = triangles,
+                                range = range,
+                                area = area,
+                                cellSize = cellSize
+                            )
+                            val color = colors[index].toColorInt()
+                            lineFeatures.add(contoursToLineFeatures(contours, color).flatten())
+                            contoursToPolygonFeatures(contours, color)
+                        }
+                    }.awaitAll()
+                    withContext(Dispatchers.Main) {
+                        if (false) setupLineLayer(
+                            style = style,
+                            sourceId = sourceId,
+                            layerId = layerId,
+                            features = lineFeatures.flatten()
+                        )
+                        setupFillLayer(
+                            style = style,
+                            sourceId = fillSourceId,
+                            layerId = fillLayerId,
+                            features = features.filterNotNull(),
+                        )
+                        Log.d(TAG, "refresh: 刷新完成")
+                    }
+                }
+            }
+        }
+    }
+
+    fun findContours(
+        triangles: List<Triangle>,
+        range: ClosedFloatingPointRange<Double>,
+        area: Rectangle,
+        cellSize: Double
+    ): List<ShapeContour> {
+        return findContours(
+            f = { v ->
+                val triangle = triangles.firstOrNull { triangle ->
+                    isPointInTriangle3D(v, listOf(triangle.x1, triangle.x2, triangle.x3))
+                }
+                (triangle?.let { triangle ->
+                    val interpolate = interpolateHeight(
+                        point = v,
+                        triangle = listOf(
+                            triangle.x1,
+                            triangle.x2,
+                            triangle.x3,
+                        )
+                    )
+                    if (interpolate.z in range) -1.0
+                    else 1.0
+                } ?: 1.0).also {
+                    Log.d(TAG, "findContours: ${v} -> ${it}")
+                }
+            },
+            area = area,
+            cellSize = cellSize,
+        )
+    }
+
+    private fun setupLineLayer(
+        style: Style,
+        sourceId: String,
+        layerId: String,
+        features: List<Feature>
+    ) {
+        style.removeStyleLayer(layerId)
+        style.removeStyleSource(sourceId)
+
+        val source = geoJsonSource(sourceId) {
+            featureCollection(FeatureCollection.fromFeatures(features))
+        }
+        style.addSource(source)
+
+        val layer = lineLayer(layerId, sourceId) {
+            lineColor(Expression.toColor(Expression.Companion.get("color"))) // 从属性获取颜色
+            lineWidth(1.0)
+            lineCap(LineCap.ROUND)
+            lineJoin(LineJoin.ROUND)
+            lineOpacity(0.8)
+        }
+        style.addLayer(layer)
+    }
+
+    private fun setupFillLayer(
+        style: Style,
+        sourceId: String,
+        layerId: String,
+        features: List<Feature>
+    ) {
+        style.removeStyleLayer(layerId)
+        style.removeStyleSource(sourceId)
+
+        val source = geoJsonSource(sourceId) {
+            featureCollection(FeatureCollection.fromFeatures(features))
+        }
+        style.addSource(source)
+
+        val layer = fillLayer(layerId, sourceId) {
+            fillColor(Expression.Companion.toColor(Expression.get("color"))) // 从属性获取颜色
+            fillOpacity(0.5)
+            fillAntialias(true)
+        }
+        style.addLayer(layer)
+    }
+
+    private var useCatmullRom: Boolean = true
+
+    fun setCatmullRom(enabled: Boolean) {
+        useCatmullRom = enabled
+    }
+
+    fun contoursToLineFeatures(contours: List<ShapeContour>, color: Int): List<List<Feature>> {
+        return contours.drop(1).map { contour ->
+            contour.segments.map { segment ->
+                LineString.fromLngLats(
+                    listOf(
+                        segment.start.toMapboxPoint(),
+                        segment.end.toMapboxPoint()
+                    )
+                )
+            }.map { lineString ->
+                Feature.fromGeometry(lineString).apply {
+                    // 将颜色Int转换为十六进制字符串
+                    addStringProperty("color", color.toHexColorString())
+                }
+            }
+        }
+    }
+
+    fun contoursToPolygonFeatures(contours: List<ShapeContour>, color: Int): Feature? {
+        val lists = contours.drop(0).filter { it.segments.isNotEmpty() }.map { contour ->
+            val start = contour.segments[0].start
+            listOf(start) + contour.segments.map { it.end }
+        }.map {
+            if (!useCatmullRom) return@map it
+            val cmr = CatmullRomChain2(it, 1.0, loop = true)
+            val contour = ShapeContour.fromPoints(cmr.positions(200), true)
+            val start = contour.segments[0].start
+            listOf(start) + contour.segments.map { it.end }
+        }.map { points -> points.map { it.toMapboxPoint() } }
+
+        if (lists.isEmpty()) {
+            Log.w(TAG, "contoursToPolygonFeatures: 没有有效的轮廓数据")
+            return null
+        }
+
+        val polygon = Polygon.fromLngLats(lists)
+        return Feature.fromGeometry(polygon).apply {
+            // 将颜色Int转换为十六进制字符串
+            addStringProperty("color", color.toHexColorString())
+        }
+    }
+
+    fun Int.toHexColorString(): String {
+        return String.format("#%06X", 0xFFFFFF and this)
+    }
+
+    fun clearContours() {
+        mapView.mapboxMap.getStyle { style ->
+            try {
+                style.removeStyleLayer(layerId)
+            } catch (_: Exception) {
+            }
+            try {
+                style.removeStyleSource(sourceId)
+            } catch (_: Exception) {
+            }
+        }
+    }
+}
+
+fun isPointInTriangle3D(point: Vector2D, triangle: List<Vector3D>): Boolean {
+    require(triangle.size == 3) { "三角形必须有3个顶点" }
+
+    val (v1, v2, v3) = triangle
+
+    // 计算重心坐标
+    val denominator = (v2.y - v3.y) * (v1.x - v3.x) + (v3.x - v2.x) * (v1.y - v3.y)
+    if (denominator == 0.0) return false // 退化三角形
+
+    val alpha = ((v2.y - v3.y) * (point.x - v3.x) + (v3.x - v2.x) * (point.y - v3.y)) / denominator
+    val beta = ((v3.y - v1.y) * (point.x - v3.x) + (v1.x - v3.x) * (point.y - v3.y)) / denominator
+    val gamma = 1.0 - alpha - beta
+
+    // 点在三角形内当且仅当所有重心坐标都在[0,1]范围内
+    return alpha >= 0 && beta >= 0 && gamma >= 0 &&
+            alpha <= 1 && beta <= 1 && gamma <= 1
+}
+
+/**
+ * 使用重心坐标计算点在三角形上的高度
+ *
+ * @param point 二维点 (x, y)
+ * @param triangle 三角形的三个顶点
+ * @return 三维点 (x, y, z)
+ */
+fun interpolateHeight(point: Vector2D, triangle: List<Vector3D>): Vector3D {
+    /**
+     * 计算点在三角形中的重心坐标
+     */
+    fun calculateBarycentricCoordinates(
+        point: Vector2D,
+        v1: Vector3D,
+        v2: Vector3D,
+        v3: Vector3D
+    ): Triple<Double, Double, Double> {
+        val denom = (v2.y - v3.y) * (v1.x - v3.x) + (v3.x - v2.x) * (v1.y - v3.y)
+
+        val alpha = ((v2.y - v3.y) * (point.x - v3.x) + (v3.x - v2.x) * (point.y - v3.y)) / denom
+        val beta = ((v3.y - v1.y) * (point.x - v3.x) + (v1.x - v3.x) * (point.y - v3.y)) / denom
+        val gamma = 1.0 - alpha - beta
+
+        return Triple(alpha, beta, gamma)
+    }
+
+    require(triangle.size == 3) { "三角形必须有3个顶点" }
+
+    val (v1, v2, v3) = triangle
+
+    // 计算重心坐标
+    val (alpha, beta, gamma) = calculateBarycentricCoordinates(point, v1, v2, v3)
+
+    // 使用重心坐标插值z值
+    val z = alpha * v1.z + beta * v2.z + gamma * v3.z
+
+    return Vector3D(point.x, point.y, z)
+}

android/src/main/java/com/icegps/geotools/ControllableArrow.kt

@@ -0,0 +1,197 @@
+package com.icegps.geotools
+
+import com.icegps.math.geometry.Angle
+import com.icegps.math.geometry.Vector2D
+import com.icegps.geotools.ktx.toMapboxPoint
+import com.mapbox.geojson.Feature
+import com.mapbox.geojson.FeatureCollection
+import com.mapbox.geojson.LineString
+import com.mapbox.geojson.Point
+import com.mapbox.geojson.Polygon
+import com.mapbox.maps.MapView
+import com.mapbox.maps.Style
+import com.mapbox.maps.extension.style.expressions.generated.Expression
+import com.mapbox.maps.extension.style.layers.addLayer
+import com.mapbox.maps.extension.style.layers.generated.FillLayer
+import com.mapbox.maps.extension.style.layers.generated.LineLayer
+import com.mapbox.maps.extension.style.layers.properties.generated.LineCap
+import com.mapbox.maps.extension.style.layers.properties.generated.LineJoin
+import com.mapbox.maps.extension.style.sources.addSource
+import com.mapbox.maps.extension.style.sources.generated.geoJsonSource
+import kotlin.math.cos
+import kotlin.math.min
+import kotlin.math.sin
+
+/**
+ * 设置趋势箭头图层
+ */
+fun setupTrendLayer(
+    style: Style,
+    trendSourceId: String,
+    trendLayerId: String,
+    features: List<Feature>
+) {
+    val trendSource = geoJsonSource(trendSourceId) {
+        featureCollection(FeatureCollection.fromFeatures(features))
+    }
+
+    try {
+        style.removeStyleLayer(trendLayerId)
+    } catch (_: Exception) {
+    }
+
+    try {
+        style.removeStyleLayer("$trendLayerId-head")
+    } catch (_: Exception) {
+    }
+
+    if (style.styleSourceExists(trendSourceId)) {
+        style.removeStyleSource(trendSourceId)
+    }
+
+    style.addSource(trendSource)
+
+    val lineLayer = LineLayer(trendLayerId, trendSourceId).apply {
+        lineColor(Expression.toColor(Expression.get("color")))
+        lineWidth(4.0)
+        lineCap(LineCap.ROUND)
+        lineJoin(LineJoin.ROUND)
+    }
+    style.addLayer(lineLayer)
+
+    val headLayer = FillLayer("$trendLayerId-head", trendSourceId).apply {
+        fillColor(Expression.toColor(Expression.get("color")))
+    }
+    style.addLayer(headLayer)
+}
+
+fun MapView.displayControllableArrow(
+    grid: GridModel,
+    sourceId: String = "controllable-source-id-0",
+    layerId: String = "controllable-layer-id-0",
+    arrowScale: Double = 0.4,
+    angle: Angle,
+    onHeadArrowChange: (List<Point>) -> Unit
+) {
+    mapboxMap.getStyle { style ->
+        val centerX = (grid.minX + grid.maxX) / 2
+        val centerY = (grid.minY + grid.maxY) / 2
+
+        val regionWidth = grid.maxX - grid.minX
+        val regionHeight = grid.maxY - grid.minY
+        val arrowLength = min(regionWidth, regionHeight) * arrowScale * 1.0
+
+        val arrowDirectionRad = angle.radians
+        val endX = centerX + sin(arrowDirectionRad) * arrowLength
+        val endY = centerY + cos(arrowDirectionRad) * arrowLength
+
+        val arrowLine = LineString.fromLngLats(
+            listOf(
+                Vector2D(centerX, centerY),
+                Vector2D(endX, endY)
+            ).map { it.toMapboxPoint() }
+        )
+
+        val arrowFeature = Feature.fromGeometry(arrowLine)
+        arrowFeature.addStringProperty("color", "#0000FF")
+        arrowFeature.addStringProperty("type", "overall-trend")
+
+        // 创建箭头头部
+        val headSize = arrowLength * 0.2
+        val leftRad = arrowDirectionRad + Math.PI * 0.8
+        val rightRad = arrowDirectionRad - Math.PI * 0.8
+
+        val leftX = endX + sin(leftRad) * headSize
+        val leftY = endY + cos(leftRad) * headSize
+        val rightX = endX + sin(rightRad) * headSize
+        val rightY = endY + cos(rightRad) * headSize
+
+        val headRing = listOf(
+            Vector2D(endX, endY),
+            Vector2D(leftX, leftY),
+            Vector2D(rightX, rightY),
+            Vector2D(endX, endY)
+        ).map { it.toMapboxPoint() }
+        onHeadArrowChange(headRing)
+        val headPolygon = Polygon.fromLngLats(listOf(headRing))
+        val headFeature = Feature.fromGeometry(headPolygon)
+        headFeature.addStringProperty("color", "#0000FF")
+        headFeature.addStringProperty("type", "overall-trend")
+
+        val features = listOf(arrowFeature, headFeature)
+
+        // 设置图层
+        setupTrendLayer(style, sourceId, layerId, features)
+    }
+}
+
+fun calculateArrowData(
+    grid: GridModel,
+    angle: Angle,
+    arrowScale: Double = 0.4
+): ArrowData {
+    val centerX = (grid.minX + grid.maxX) / 2
+    val centerY = (grid.minY + grid.maxY) / 2
+
+    val regionWidth = grid.maxX - grid.minX
+    val regionHeight = grid.maxY - grid.minY
+    val arrowLength = min(regionWidth, regionHeight) * arrowScale * 1.0
+
+    val arrowDirectionRad = angle.radians
+    val endX = centerX + sin(arrowDirectionRad) * arrowLength
+    val endY = centerY + cos(arrowDirectionRad) * arrowLength
+
+    val arrowLine = listOf(
+        Vector2D(centerX, centerY),
+        Vector2D(endX, endY)
+    )
+
+    // 创建箭头头部
+    val headSize = arrowLength * 0.2
+    val leftRad = arrowDirectionRad + Math.PI * 0.8
+    val rightRad = arrowDirectionRad - Math.PI * 0.8
+
+    val leftX = endX + sin(leftRad) * headSize
+    val leftY = endY + cos(leftRad) * headSize
+    val rightX = endX + sin(rightRad) * headSize
+    val rightY = endY + cos(rightRad) * headSize
+
+    val headRing = listOf(
+        Vector2D(endX, endY),
+        Vector2D(leftX, leftY),
+        Vector2D(rightX, rightY),
+        Vector2D(endX, endY)
+    )
+    return ArrowData(
+        arrowLine = arrowLine,
+        headRing = headRing
+    )
+}
+
+data class ArrowData(
+    val arrowLine: List<Vector2D>,
+    val headRing: List<Vector2D>
+)
+
+fun MapView.displayControllableArrow(
+    sourceId: String = "controllable-source-id-0",
+    layerId: String = "controllable-layer-id-0",
+    arrowData: ArrowData
+) {
+    mapboxMap.getStyle { style ->
+        val (arrowLine, headRing) = arrowData
+        val arrowFeature = Feature.fromGeometry(LineString.fromLngLats(arrowLine.map { it.toMapboxPoint() }))
+        arrowFeature.addStringProperty("color", "#0000FF")
+        arrowFeature.addStringProperty("type", "overall-trend")
+
+        val headPolygon = Polygon.fromLngLats(listOf(headRing.map { it.toMapboxPoint() }))
+        val headFeature = Feature.fromGeometry(headPolygon)
+        headFeature.addStringProperty("color", "#0000FF")
+        headFeature.addStringProperty("type", "overall-trend")
+
+        val features = listOf(arrowFeature, headFeature)
+
+        // 设置图层
+        setupTrendLayer(style, sourceId, layerId, features)
+    }
+}

android/src/main/java/com/icegps/geotools/CoordinateGenerator.kt

@@ -0,0 +1,53 @@
+package com.icegps.geotools
+
+import com.icegps.math.geometry.Angle
+import com.icegps.math.geometry.Vector3D
+import com.icegps.math.geometry.degrees
+import kotlin.math.cos
+import kotlin.math.sin
+import kotlin.random.Random
+
+/**
+ * @author tabidachinokaze
+ * @date 2025/11/25
+ */
+fun coordinateGenerate(): List<Vector3D> {
+    val minX = -20.0
+    val maxX = 20.0
+    val minY = -20.0
+    val maxY = 20.0
+    val minZ = -20.0
+    val maxZ = 20.0
+    val x: () -> Double = { Random.nextDouble(minX, maxX) }
+    val y: () -> Double = { Random.nextDouble(minY, maxY) }
+    val z: () -> Double = { Random.nextDouble(minZ, maxZ) }
+    val dPoints = (0..60).map {
+        Vector3D(x(), y(), z())
+    }
+    return dPoints
+}
+
+fun coordinateGenerate1(): List<List<Vector3D>> {
+    /**
+     * 绕 Z 轴旋转指定角度（弧度）
+     */
+    fun Vector3D.rotateAroundZ(angle: Angle): Vector3D {
+        val cosAngle = cos(angle.radians)
+        val sinAngle = sin(angle.radians)
+
+        return Vector3D(
+            x = x * cosAngle - y * sinAngle,
+            y = x * sinAngle + y * cosAngle,
+            z = z
+        )
+    }
+
+    val center = Vector3D()
+    val direction = Vector3D(0.0, 1.0, -1.0)
+    return (0..360).step(10).map {
+        val nowDirection = direction.rotateAroundZ(it.degrees)
+        listOf(2, 6, 10).map {
+            center + nowDirection * it
+        }
+    }
+}

android/src/main/java/com/icegps/geotools/DisplaySlopeResult.kt

@@ -0,0 +1,144 @@
+package com.icegps.geotools
+
+import android.util.Log
+import com.icegps.math.geometry.Vector2D
+import com.icegps.geotools.ktx.toMapboxPoint
+import com.mapbox.geojson.Feature
+import com.mapbox.geojson.FeatureCollection
+import com.mapbox.geojson.Polygon
+import com.mapbox.maps.MapView
+import com.mapbox.maps.Style
+import com.mapbox.maps.extension.style.expressions.generated.Expression
+import com.mapbox.maps.extension.style.layers.addLayer
+import com.mapbox.maps.extension.style.layers.generated.FillLayer
+import com.mapbox.maps.extension.style.layers.generated.LineLayer
+import com.mapbox.maps.extension.style.sources.addSource
+import com.mapbox.maps.extension.style.sources.generated.geoJsonSource
+
+/**
+ * @author tabidachinokaze
+ * @date 2025/11/26
+ */
+/**
+ * 绘制斜坡设计结果
+ */
+fun MapView.displaySlopeResult(
+    originalGrid: GridModel,
+    slopeResult: SlopeResult,
+    sourceId: String = "slope-result",
+    layerId: String = "slope-layer",
+    palette: (Double?) -> String,
+    showDesignHeight: Boolean
+) {
+    val elevationList = mutableListOf<Double>()
+    mapboxMap.getStyle { style ->
+        val features = mutableListOf<Feature>()
+        val designGrid = slopeResult.designSurface
+
+        // 对比测试，将绘制到原来图形的左边
+        // val minX = originalGrid.minX * 2 - originalGrid.maxX
+        val minX = originalGrid.minX
+        val maxY = originalGrid.maxY
+
+        val cellSize = originalGrid.cellSize
+
+        for (r in 0 until originalGrid.rows) {
+            for (c in 0 until originalGrid.cols) {
+                val originalElev = originalGrid.getValue(r, c) ?: continue
+                val designElev = designGrid.getValue(r, c) ?: continue
+                elevationList.add(designElev)
+
+                // 计算填挖高度
+                val heightDiff = designElev - originalElev
+
+                // 计算栅格边界
+                val x0 = minX + c * cellSize
+                val y0 = maxY - r * cellSize
+                val x1 = x0 + cellSize
+                val y1 = y0 - cellSize
+
+                // 1. 创建多边形要素（背景色）
+                val ring = listOf(
+                    Vector2D(x0, y0),
+                    Vector2D(x1, y0),
+                    Vector2D(x1, y1),
+                    Vector2D(x0, y1),
+                    Vector2D(x0, y0)
+                ).map { it.toMapboxPoint() }
+                val poly = Polygon.fromLngLats(listOf(ring))
+                val feature = Feature.fromGeometry(poly)
+
+                if (showDesignHeight) {
+                    // 显示设计高度，测试坡向是否正确，和高度是否计算正确
+                    feature.addStringProperty("color", palette(designElev))
+                } else {
+                    // 显示高差
+                    feature.addStringProperty("color", palette(heightDiff))
+                }
+                // 显示原始高度
+                // feature.addStringProperty("color", palette(originalElev))
+                features.add(feature)
+            }
+        }
+
+        Log.d("displayGridWithDirectionArrows", "对比区域的土方量计算: ${elevationList.sum()}, 平均值：${elevationList.average()}")
+
+        // 设置图层
+        setupEarthworkLayer(style, sourceId, layerId, features)
+    }
+}
+
+/**
+ * 完整的土方工程图层设置 - 修正版
+ */
+private fun setupEarthworkLayer(
+    style: Style,
+    sourceId: String,
+    layerId: String,
+    features: List<Feature>,
+) {
+    // 创建数据源
+    val source = geoJsonSource(sourceId) {
+        featureCollection(FeatureCollection.fromFeatures(features))
+    }
+
+    // 清理旧图层
+    try {
+        style.removeStyleLayer(layerId)
+    } catch (_: Exception) {
+    }
+    try {
+        style.removeStyleLayer("$layerId-arrow")
+    } catch (_: Exception) {
+    }
+    try {
+        style.removeStyleLayer("$layerId-outline")
+    } catch (_: Exception) {
+    }
+    try {
+        style.removeStyleLayer("$layerId-text")
+    } catch (_: Exception) {
+    }
+
+    if (style.styleSourceExists(sourceId)) {
+        style.removeStyleSource(sourceId)
+    }
+
+    // 添加数据源
+    style.addSource(source)
+
+    // 主填充图层
+    val fillLayer = FillLayer(layerId, sourceId).apply {
+        fillColor(Expression.toColor(Expression.get("color")))
+        fillOpacity(0.7)
+    }
+    style.addLayer(fillLayer)
+
+    // 边框图层
+    val outlineLayer = LineLayer("$layerId-outline", sourceId).apply {
+        lineColor("#333333")
+        lineWidth(1.0)
+        lineOpacity(0.5)
+    }
+    style.addLayer(outlineLayer)
+}

android/src/main/java/com/icegps/geotools/EarthworkManager.kt

@@ -0,0 +1,438 @@
+package com.icegps.geotools
+
+import android.graphics.PointF
+import android.util.Log
+import com.icegps.common.helper.GeoHelper
+import com.icegps.math.geometry.Angle
+import com.icegps.math.geometry.Vector2D
+import com.icegps.math.geometry.degrees
+import com.icegps.shared.ktx.TAG
+import com.mapbox.android.gestures.MoveGestureDetector
+import com.mapbox.geojson.Point
+import com.mapbox.maps.MapView
+import com.mapbox.maps.ScreenCoordinate
+import com.mapbox.maps.plugin.gestures.OnMoveListener
+import com.mapbox.maps.plugin.gestures.addOnMoveListener
+import com.mapbox.maps.plugin.gestures.removeOnMoveListener
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.launchIn
+import kotlin.math.abs
+import kotlin.math.cos
+import kotlin.math.sin
+
+/**
+ * @author tabidachinokaze
+ * @date 2025/11/26
+ */
+object SlopeCalculator {
+    fun calculateSlope(
+        grid: GridModel,
+        slopeDirection: Double,
+        slopePercentage: Double,
+        baseHeightOffset: Double = 0.0
+    ): SlopeResult {
+        val centerX = (grid.minX + grid.maxX) / 2
+        val centerY = (grid.minY + grid.maxY) / 2
+
+        val elevations = grid.cells.filterNotNull()
+        val baseElevation = elevations.average() + baseHeightOffset
+
+        val basePoint = Triple(centerX, centerY, baseElevation)
+
+        val earthworkResult = EarthworkCalculator.calculateForSlopeDesign(
+            grid = grid,
+            basePoint = basePoint,
+            slope = slopePercentage,
+            aspect = slopeDirection
+        )
+
+        return SlopeResult(
+            slopeDirection = slopeDirection,
+            slopePercentage = slopePercentage,
+            baseHeightOffset = baseHeightOffset,
+            baseElevation = baseElevation,
+            earthworkResult = earthworkResult,
+            designSurface = generateSlopeDesignGrid(
+                grid = grid,
+                basePoint = basePoint,
+                slopePercentage = slopePercentage,
+                slopeDirection = slopeDirection
+            )
+        )
+    }
+
+
+    /**
+     * 生成斜坡设计面网格（用于可视化）
+     */
+    private fun generateSlopeDesignGrid(
+        grid: GridModel,
+        basePoint: Triple<Double, Double, Double>,
+        slopePercentage: Double,
+        slopeDirection: Double
+    ): GridModel {
+        val designCells = Array<Double?>(grid.rows * grid.cols) { null }
+        val (baseX, baseY, baseElev) = basePoint
+        val slopeRatio = slopePercentage / 100.0
+
+        for (r in 0 until grid.rows) {
+            for (c in 0 until grid.cols) {
+                if (grid.getValue(r, c) != null) {
+                    val cellX = grid.minX + (c + 0.5) * (grid.maxX - grid.minX) / grid.cols
+                    val cellY = grid.minY + (r + 0.5) * (grid.maxY - grid.minY) / grid.rows
+
+                    val designElev = calculateSlopeElevation(
+                        pointX = cellX,
+                        pointY = cellY,
+                        baseX = baseX,
+                        baseY = baseY,
+                        baseElev = baseElev,
+                        slopeRatio = slopeRatio,
+                        slopeDirection = slopeDirection
+                    )
+                    designCells[r * grid.cols + c] = designElev
+                }
+            }
+        }
+        return GridModel(
+            minX = grid.minX,
+            maxX = grid.maxX,
+            minY = grid.minY,
+            maxY = grid.maxY,
+            rows = grid.rows,
+            cols = grid.cols,
+            cellSize = grid.cellSize,
+            cells = designCells
+        )
+    }
+
+    /**
+     * 斜坡高程计算
+     */
+    fun calculateSlopeElevation(
+        pointX: Double,
+        pointY: Double,
+        baseX: Double,
+        baseY: Double,
+        baseElev: Double,
+        slopeRatio: Double,
+        slopeDirection: Double
+    ): Double {
+        val dx = (pointX - baseX) * cos(Math.toRadians(baseY))
+        val dy = (pointY - baseY)
+
+        val slopeRad = (slopeDirection.degrees - 90.degrees).normalized.radians
+
+        val projection = dx * cos(slopeRad) + dy * sin(slopeRad)
+        val heightDiff = projection * slopeRatio
+
+        return baseElev + heightDiff
+    }
+}
+
+/**
+ * 斜面设计
+ *
+ * @property slopeDirection 坡向 (度)
+ * @property slopePercentage 坡度 (%)
+ * @property baseHeightOffset 基准面高度偏移 (m)
+ * @property baseElevation 基准点高程 (m)
+ * @property earthworkResult 土方量结果
+ * @property designSurface 设计面网格（用于可视化）
+ */
+data class SlopeResult(
+    val slopeDirection: Double,
+    val slopePercentage: Double,
+    val baseHeightOffset: Double,
+    val baseElevation: Double,
+    val earthworkResult: EarthworkResult,
+    val designSurface: GridModel
+)
+
+object EarthworkCalculator {
+    /**
+     * @param grid 栅格网模型
+     * @param designElevation 设计高程
+     */
+    fun calculateForFlatDesign(
+        grid: GridModel,
+        designElevation: Double
+    ): EarthworkResult {
+        var cutVolume = 0.0
+        var fillVolume = 0.0
+        var cutArea = 0.0
+        var fillArea = 0.0
+        val cellArea = grid.cellSize * grid.cellSize
+
+        for (r in 0 until grid.rows) {
+            for (c in 0 until grid.cols) {
+                val originalElev = grid.getValue(r, c) ?: continue
+
+                val heightDiff = designElevation - originalElev
+
+                val volume = heightDiff * cellArea
+
+                if (volume > 0) {
+                    fillVolume += volume
+                    fillArea += cellArea
+                } else if (volume < 0) {
+                    cutVolume += abs(volume)
+                    cutArea += cellArea
+                }
+            }
+        }
+
+        return EarthworkResult(
+            cutVolume = cutVolume,
+            fillVolume = fillVolume,
+            netVolume = fillVolume - cutVolume,
+            cutArea = cutArea,
+            fillArea = fillArea,
+            totalArea = cutArea + fillArea
+        )
+    }
+
+    /**
+     * 计算斜面设计的土方量
+     */
+    fun calculateForSlopeDesign(
+        grid: GridModel,
+        basePoint: Triple<Double, Double, Double>,
+        slope: Double,
+        aspect: Double
+    ): EarthworkResult {
+        var cutVolume = 0.0
+        var fillVolume = 0.0
+        var cutArea = 0.0
+        var fillArea = 0.0
+        val cellArea = grid.cellSize * grid.cellSize
+
+        val (baseX, baseY, baseElev) = basePoint
+        val slopeRatio = slope / 100.0
+
+        for (r in 0 until grid.rows) {
+            for (c in 0 until grid.cols) {
+                val originalElev = grid.getValue(r, c) ?: continue
+
+                val cellX = grid.minX + (c + 0.5) * (grid.maxX - grid.minX) / grid.cols
+                val cellY = grid.minY + (r + 0.5) * (grid.maxY - grid.minY) / grid.rows
+
+                val designElev = SlopeCalculator.calculateSlopeElevation(
+                    pointX = cellX,
+                    pointY = cellY,
+                    baseX = baseX,
+                    baseY = baseY,
+                    baseElev = baseElev,
+                    slopeRatio = slopeRatio,
+                    slopeDirection = aspect
+                )
+
+                val heightElev = designElev - originalElev
+                val volume = heightElev * cellArea
+
+                if (volume > 0) {
+                    fillVolume += volume
+                    fillArea += cellArea
+                } else if (volume < 0) {
+                    cutVolume += abs(volume)
+                    cutArea += cellArea
+                }
+            }
+        }
+
+        return EarthworkResult(
+            cutVolume = cutVolume,
+            fillVolume = fillVolume,
+            netVolume = fillVolume - cutVolume,
+            cutArea = cutArea,
+            fillArea = fillArea,
+            totalArea = cutArea + fillArea
+        )
+    }
+}
+
+/**
+ * 土方量计算结果
+ * @property cutVolume 挖方量 (m³)
+ * @property fillVolume 填方量 (m³)
+ * @property netVolume 净土方量 (m³)
+ * @property cutArea 挖方面积 (m²)
+ * @property fillArea 填方面积 (m²)
+ * @property totalArea 总面积 (m²)
+ */
+data class EarthworkResult(
+    val cutVolume: Double,
+    val fillVolume: Double,
+    val netVolume: Double,
+    val cutArea: Double,
+    val fillArea: Double,
+    val totalArea: Double
+) {
+    override fun toString(): String {
+        return buildString {
+            appendLine("EarthworkResult")
+            appendLine("挖方: ${"%.1f".format(cutVolume)} m³")
+            appendLine("填方: ${"%.1f".format(fillVolume)} m³")
+            appendLine("净土方: ${"%.1f".format(netVolume)} m³")
+            appendLine("挖方面积: ${"%.1f".format(cutArea)} m²")
+            appendLine("填方面积: ${"%.1f".format(fillArea)} m²")
+            appendLine("总面积：${"%.1f".format(totalArea)} m²")
+        }
+    }
+}
+
+class EarthworkManager(
+    private val mapView: MapView,
+    private val scope: CoroutineScope
+) {
+    private val arrowSourceId: String = "controllable-source-id-0"
+    private val arrowLayerId: String = "controllable-layer-id-0"
+    private var listener: OnMoveListener? = null
+
+    private var gridModel = MutableStateFlow<GridModel?>(null)
+    private val arrowHead = MutableStateFlow(emptyList<Vector2D>())
+    private var arrowCenter = MutableStateFlow(Vector2D(0.0, 0.0))
+    private var arrowEnd = MutableStateFlow(Vector2D(0.0, 1.0))
+    private var _slopeDirection = MutableStateFlow(0.degrees)
+    val slopeDirection = _slopeDirection.asStateFlow()
+    private val _slopePercentage = MutableStateFlow(90.0)
+    val slopePercentage = _slopePercentage.asStateFlow()
+    private val _baseHeightOffset = MutableStateFlow(0.0)
+    val baseHeightOffset = _baseHeightOffset.asStateFlow()
+
+    init {
+        combine(
+            arrowCenter,
+            arrowEnd,
+            gridModel
+        ) { center, arrow, gridModel ->
+            gridModel?.let { gridModel ->
+                // _slopeDirection.value = angle
+                displayControllableArrow(gridModel, getSlopeDirection(arrow, center))
+            }
+        }.launchIn(scope)
+        combine(
+            _slopeDirection,
+            gridModel
+        ) { slopeDirection, gridModel ->
+            gridModel?.let {
+                displayControllableArrow(it, slopeDirection)
+            }
+        }.launchIn(scope)
+    }
+
+    private fun getSlopeDirection(
+        arrow: Vector2D,
+        center: Vector2D
+    ): Angle {
+        val direction = (arrow - center)
+        val atan2 = Angle.atan2(direction.x, direction.y, Vector2D.UP)
+        val angle = atan2.normalized
+        return angle
+    }
+
+    private fun displayControllableArrow(gridModel: GridModel, slopeDirection: Angle) {
+        val arrowData = calculateArrowData(
+            grid = gridModel,
+            angle = slopeDirection,
+        )
+        arrowHead.value = arrowData.headRing
+        mapView.displayControllableArrow(
+            sourceId = arrowSourceId,
+            layerId = arrowLayerId,
+            arrowData = arrowData,
+        )
+    }
+
+    fun Point.toVector2D(): Vector2D {
+        val geoHelper = GeoHelper.getSharedInstance()
+        val enu = geoHelper.wgs84ToENU(lon = longitude(), lat = latitude(), hgt = 0.0)
+        return Vector2D(enu.x, enu.y)
+    }
+
+    fun removeOnMoveListener() {
+        listener?.let(mapView.mapboxMap::removeOnMoveListener)
+        listener = null
+    }
+
+    fun setupOnMoveListener() {
+        listener = object : OnMoveListener {
+            private var beginning: Boolean = false
+            private var isDragging: Boolean = false
+            private fun getCoordinate(focalPoint: PointF): Point {
+                return mapView.mapboxMap.coordinateForPixel(ScreenCoordinate(focalPoint.x.toDouble(), focalPoint.y.toDouble()))
+            }
+
+            override fun onMove(detector: MoveGestureDetector): Boolean {
+                val focalPoint = detector.focalPoint
+                val point = mapView.mapboxMap
+                    .coordinateForPixel(ScreenCoordinate(focalPoint.x.toDouble(), focalPoint.y.toDouble()))
+                    .toVector2D()
+
+                val isPointInPolygon = RayCastingAlgorithm.isPointInPolygon(
+                    point = point,
+                    polygon = arrowHead.value
+                )
+
+                if (isPointInPolygon) {
+                    isDragging = true
+                }
+                if (isDragging) {
+                    arrowEnd.value = point
+                }
+                return isDragging
+            }
+
+            override fun onMoveBegin(detector: MoveGestureDetector) {
+                Log.d(TAG, "onMoveBegin: $detector")
+                beginning = true
+            }
+
+            override fun onMoveEnd(detector: MoveGestureDetector) {
+                Log.d(TAG, "onMoveEnd: $detector")
+                val point = getCoordinate(detector.focalPoint)
+                val arrow = point.toVector2D()
+                if (beginning && isDragging) {
+                    arrowEnd.value = arrow
+                    val center = arrowCenter.value
+                    _slopeDirection.value = getSlopeDirection(arrow, center)
+                }
+                Log.d(
+                    TAG,
+                    buildString {
+                        appendLine("onMoveEnd: ")
+                        appendLine("${point.longitude()}, ${point.latitude()}")
+                    }
+                )
+                isDragging = false
+                beginning = false
+            }
+        }.also(mapView.mapboxMap::addOnMoveListener)
+    }
+
+    fun updateGridModel(gridModel: GridModel) {
+        this.gridModel.value = gridModel
+        calculateArrowCenter(gridModel)
+    }
+
+    private fun calculateArrowCenter(gridModel: GridModel) {
+        val centerX = (gridModel.minX + gridModel.maxX) / 2
+        val centerY = (gridModel.minY + gridModel.maxY) / 2
+        arrowCenter.value = Vector2D(centerX, centerY)
+    }
+
+    fun updateSlopeDirection(angle: Angle) {
+        _slopeDirection.value = angle
+    }
+
+    fun updateSlopePercentage(value: Double) {
+        _slopePercentage.value = value
+    }
+
+    fun updateDesignHeight(value: Double) {
+        _baseHeightOffset.value = value
+    }
+}

android/src/main/java/com/icegps/geotools/GridDisplay.kt

@@ -0,0 +1,83 @@
+package com.icegps.geotools
+
+import com.icegps.common.helper.GeoHelper
+import com.icegps.math.geometry.Vector2D
+import com.mapbox.geojson.Feature
+import com.mapbox.geojson.FeatureCollection
+import com.mapbox.geojson.Point
+import com.mapbox.geojson.Polygon
+import com.mapbox.maps.MapView
+import com.mapbox.maps.extension.style.expressions.generated.Expression
+import com.mapbox.maps.extension.style.layers.addLayer
+import com.mapbox.maps.extension.style.layers.generated.FillLayer
+import com.mapbox.maps.extension.style.sources.addSource
+import com.mapbox.maps.extension.style.sources.generated.geoJsonSource
+
+/**
+ * @author tabidachinokaze
+ * @date 2025/11/25
+ */
+fun MapView.displayGridModel(
+    grid: GridModel,
+    sourceId: String,
+    layerId: String,
+    palette: (Double?) -> String,
+) {
+    val geoHelper = GeoHelper.getSharedInstance()
+    mapboxMap.getStyle { style ->
+        val polygonFeatures = mutableListOf<Feature>()
+
+        val minX = grid.minX
+        val maxY = grid.maxY
+        val cellSize = grid.cellSize
+
+        for (r in 0 until grid.rows) {
+            for (c in 0 until grid.cols) {
+                val idx = r * grid.cols + c
+                val v = grid.cells[idx] ?: continue
+
+                val x0 = minX + c * cellSize
+                val y0 = maxY - r * cellSize
+                val x1 = x0 + cellSize
+                val y1 = y0 - cellSize
+
+                val ring = listOf(
+                    Vector2D(x0, y0),
+                    Vector2D(x1, y0),
+                    Vector2D(x1, y1),
+                    Vector2D(x0, y1),
+                    Vector2D(x0, y0),
+                ).map {
+                    geoHelper.enuToWGS84Object(GeoHelper.ENU(it.x, it.y))
+                }.map {
+                    Point.fromLngLat(it.lon, it.lat)
+                }
+                val poly = Polygon.fromLngLats(listOf(ring))
+                val polyFeature = Feature.fromGeometry(poly)
+                polyFeature.addStringProperty("color", palette(v))
+                polyFeature.addNumberProperty("value", v ?: -9999.0)
+                polygonFeatures.add(polyFeature)
+            }
+        }
+
+        try {
+            style.removeStyleLayer(layerId)
+        } catch (_: Exception) {
+        }
+
+        if (style.styleSourceExists(sourceId)) {
+            style.removeStyleSource(sourceId)
+        }
+
+        val polygonSource = geoJsonSource(sourceId) {
+            featureCollection(FeatureCollection.fromFeatures(polygonFeatures))
+        }
+        style.addSource(polygonSource)
+
+        val fillLayer = FillLayer(layerId, sourceId).apply {
+            fillColor(Expression.toColor(Expression.get("color")))
+            fillOpacity(0.5)
+        }
+        style.addLayer(fillLayer)
+    }
+}

android/src/main/java/com/icegps/geotools/GridModel.kt

@@ -0,0 +1,139 @@
+package com.icegps.geotools
+
+import com.icegps.math.geometry.Vector2D
+import com.icegps.math.geometry.Vector3D
+import com.icegps.triangulation.DelaunayTriangulation
+import kotlin.math.absoluteValue
+import kotlin.math.ceil
+
+/**
+ * @author tabidachinokaze
+ * @date 2025/11/25
+ */
+data class GridModel(
+    val minX: Double,
+    val maxX: Double,
+    val minY: Double,
+    val maxY: Double,
+    val rows: Int,
+    val cols: Int,
+    val cellSize: Double,
+    val cells: Array<Double?>
+) {
+    fun getValue(row: Int, col: Int): Double? {
+        if (row !in 0..<rows || col < 0 || col >= cols) {
+            return null
+        }
+        return cells[row * cols + col]
+    }
+}
+
+fun triangulationToGrid(
+    delaunator: DelaunayTriangulation,
+    cellSize: Double = 50.0,
+    maxSidePixels: Int = 5000
+): GridModel {
+    fun pointInTriangle(pt: Vector2D, a: Vector3D, b: Vector3D, c: Vector3D): Boolean {
+        val v0x = c.x - a.x
+        val v0y = c.y - a.y
+        val v1x = b.x - a.x
+        val v1y = b.y - a.y
+        val v2x = pt.x - a.x
+        val v2y = pt.y - a.y
+
+        val dot00 = v0x * v0x + v0y * v0y
+        val dot01 = v0x * v1x + v0y * v1y
+        val dot02 = v0x * v2x + v0y * v2y
+        val dot11 = v1x * v1x + v1y * v1y
+        val dot12 = v1x * v2x + v1y * v2y
+
+        val denom = dot00 * dot11 - dot01 * dot01
+        if (denom == 0.0) return false
+        val invDenom = 1.0 / denom
+        val u = (dot11 * dot02 - dot01 * dot12) * invDenom
+        val v = (dot00 * dot12 - dot01 * dot02) * invDenom
+        return u >= 0 && v >= 0 && u + v <= 1
+    }
+
+    fun barycentricInterpolateLegacy(pt: Vector2D, a: Vector3D, b: Vector3D, c: Vector3D, values: DoubleArray): Double {
+        val area = { p1: Vector2D, p2: Vector3D, p3: Vector3D ->
+            ((p2.x - p1.x) * (p3.y - p1.y) - (p3.x - p1.x) * (p2.y - p1.y)).absoluteValue / 2.0
+        }
+        val area2 = { p1: Vector3D, p2: Vector3D, p3: Vector3D ->
+            ((p2.x - p1.x) * (p3.y - p1.y) - (p3.x - p1.x) * (p2.y - p1.y)).absoluteValue / 2.0
+        }
+        val areaTotal = area2(a, b, c)
+        if (areaTotal == 0.0) return values[0]
+        val wA = area(pt, b, c) / areaTotal
+        val wB = area(pt, c, a) / areaTotal
+        val wC = area(pt, a, b) / areaTotal
+        return values[0] * wA + values[1] * wB + values[2] * wC
+    }
+
+
+    val pts = delaunator.points
+    require(pts.isNotEmpty()) { "points empty" }
+
+    val x = pts.map { it.x }
+    val y = pts.map { it.y }
+    val minX = x.min()
+    val maxX = x.max()
+    val minY = y.min()
+    val maxY = y.max()
+
+    val width = maxX - minX
+    val height = maxY - minY
+
+    var cols = ceil(width / cellSize).toInt()
+    var rows = ceil(height / cellSize).toInt()
+
+    // 防止过大
+    if (cols > maxSidePixels) cols = maxSidePixels
+    if (rows > maxSidePixels) rows = maxSidePixels
+
+    val cells = Array<Double?>(rows * cols) { null }
+
+
+    val triangles = delaunator.triangles()
+
+    for (ti in 0 until triangles.size) {
+        val (a, b, c) = triangles[ti]
+
+        val tminX = minOf(a.x, b.x, c.x)
+        val tmaxX = maxOf(a.x, b.x, c.x)
+        val tminY = minOf(a.y, b.y, c.y)
+        val tmaxY = maxOf(a.y, b.y, c.y)
+
+        val colMin = ((tminX - minX) / cellSize).toInt().coerceIn(0, cols - 1)
+        val colMax = ((tmaxX - minX) / cellSize).toInt().coerceIn(0, cols - 1)
+        val rowMin = ((maxY - tmaxY) / cellSize).toInt().coerceIn(0, rows - 1)
+        val rowMax = ((maxY - tminY) / cellSize).toInt().coerceIn(0, rows - 1)
+
+        val triVertexVals = doubleArrayOf(a.z, b.z, c.z)
+
+        for (r in rowMin..rowMax) {
+            for (cIdx in colMin..colMax) {
+                val centerX = minX + (cIdx + 0.5) * cellSize
+                val centerY = maxY - (r + 0.5) * cellSize
+                val pt = Vector2D(centerX, centerY)
+                if (pointInTriangle(pt, a, b, c)) {
+                    val idx = r * cols + cIdx
+                    val valInterp = barycentricInterpolateLegacy(pt, a, b, c, triVertexVals)
+                    cells[idx] = valInterp
+                }
+            }
+        }
+    }
+
+    val grid = GridModel(
+        minX = minX,
+        minY = minY,
+        maxX = maxX,
+        maxY = maxY,
+        rows = rows,
+        cols = cols,
+        cellSize = cellSize,
+        cells = cells
+    )
+    return grid
+}

android/src/main/java/com/icegps/geotools/MainActivity.kt

@@ -0,0 +1,265 @@
+package com.icegps.geotools
+
+import android.os.Bundle
+import androidx.activity.enableEdgeToEdge
+import androidx.appcompat.app.AppCompatActivity
+import androidx.core.view.ViewCompat
+import androidx.core.view.WindowInsetsCompat
+import androidx.lifecycle.ViewModelProvider
+import androidx.lifecycle.lifecycleScope
+import com.google.android.material.slider.RangeSlider
+import com.google.android.material.slider.Slider
+import com.icegps.common.helper.GeoHelper
+import com.icegps.geotools.databinding.ActivityMainBinding
+import com.icegps.math.geometry.Angle
+import com.icegps.math.geometry.degrees
+import com.icegps.shared.model.GeoPoint
+import com.mapbox.geojson.Point
+import com.mapbox.maps.CameraOptions
+import com.mapbox.maps.MapView
+import com.mapbox.maps.plugin.gestures.addOnMapClickListener
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.filterNotNull
+import kotlinx.coroutines.flow.launchIn
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.onEach
+import kotlin.uuid.ExperimentalUuidApi
+import kotlin.uuid.Uuid
+
+class MainActivity : AppCompatActivity() {
+    private lateinit var binding: ActivityMainBinding
+    private lateinit var mapView: MapView
+    private val viewModel: MainViewModel by lazy {
+        ViewModelProvider(this)[MainViewModel::class.java]
+    }
+    private lateinit var contoursManager: ContoursManager
+    private lateinit var earthworkManager: EarthworkManager
+
+    init {
+        initGeoHelper()
+    }
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        enableEdgeToEdge()
+        binding = ActivityMainBinding.inflate(layoutInflater)
+        mapView = binding.mapView
+        earthworkManager = EarthworkManager(mapView, lifecycleScope)
+        setContentView(binding.root)
+        ViewCompat.setOnApplyWindowInsetsListener(findViewById(R.id.main)) { v, insets ->
+            val systemBars = insets.getInsets(WindowInsetsCompat.Type.systemBars())
+            v.setPadding(systemBars.left, systemBars.top, systemBars.right, systemBars.bottom)
+            insets
+        }
+
+        mapView.mapboxMap.setCamera(
+            CameraOptions.Builder()
+                .center(Point.fromLngLat(home.longitude, home.latitude))
+                .pitch(0.0)
+                .zoom(18.0)
+                .bearing(0.0)
+                .build()
+        )
+
+        val points = coordinateGenerate()
+
+        // divider
+        contoursManager = ContoursManager(
+            context = this,
+            mapView = mapView,
+            scope = lifecycleScope
+        )
+        contoursManager.updateContourSize(6)
+        contoursManager.updatePoints(points)
+        val height = points.map { it.z }
+        val min = height.min()
+        val max = height.max()
+        contoursManager.updateHeightRange((min / 2)..max)
+        binding.heightRange.values = listOf(min.toFloat() / 2, max.toFloat())
+        binding.heightRange.valueFrom = min.toFloat()
+        binding.heightRange.valueTo = max.toFloat()
+        contoursManager.refresh()
+
+        binding.sliderTargetHeight.addOnSliderTouchListener(
+            object : Slider.OnSliderTouchListener {
+                override fun onStartTrackingTouch(p0: Slider) {
+                }
+
+                override fun onStopTrackingTouch(p0: Slider) {
+                    val present = p0.value / p0.valueTo
+                    // val targetHeight = ((valueRange.endInclusive - valueRange.start) * present) + valueRange.start
+
+                    // val contours = findContours(triangles, targetHeight)
+                    // contoursTest.clearContours()
+                    // if (false) contoursTest.updateContours(contours)
+                }
+            }
+        )
+
+        binding.heightRange.addOnSliderTouchListener(
+            object : RangeSlider.OnSliderTouchListener {
+                override fun onStartTrackingTouch(slider: RangeSlider) {
+                }
+
+                override fun onStopTrackingTouch(slider: RangeSlider) {
+                    contoursManager.updateHeightRange((slider.values.min().toDouble() - 1.0)..(slider.values.max().toDouble() + 1.0))
+                    contoursManager.refresh()
+                }
+            }
+        )
+
+        binding.switchGrid.setOnCheckedChangeListener { _, isChecked ->
+            contoursManager.setGridVisible(isChecked)
+        }
+        binding.switchTriangle.setOnCheckedChangeListener { _, isChecked ->
+            contoursManager.setTriangleVisible(isChecked)
+        }
+        binding.update.setOnClickListener {
+            contoursManager.refresh()
+        }
+        binding.cellSize.addOnSliderTouchListener(
+            object : Slider.OnSliderTouchListener {
+                override fun onStartTrackingTouch(slider: Slider) {
+                }
+
+                override fun onStopTrackingTouch(slider: Slider) {
+                    contoursManager.updateCellSize(slider.value.toDouble())
+                    contoursManager.refresh()
+                }
+            }
+        )
+        mapView.mapboxMap.addOnMapClickListener {
+            viewModel.addPoint(it)
+            true
+        }
+        binding.clearPoints.setOnClickListener {
+            viewModel.clearPoints()
+        }
+        binding.slopeDirection.addOnSliderTouchListener(
+            object : Slider.OnSliderTouchListener {
+                override fun onStartTrackingTouch(slider: Slider) {
+                }
+
+                override fun onStopTrackingTouch(slider: Slider) {
+                    earthworkManager.updateSlopeDirection(slider.value.degrees)
+                }
+            }
+        )
+        binding.slopePercentage.addOnSliderTouchListener(
+            object : Slider.OnSliderTouchListener {
+                override fun onStartTrackingTouch(slider: Slider) {
+                }
+
+                override fun onStopTrackingTouch(slider: Slider) {
+                    earthworkManager.updateSlopePercentage(slider.value.toDouble())
+                }
+            }
+        )
+        binding.designHeight.addOnSliderTouchListener(
+            object : Slider.OnSliderTouchListener {
+                override fun onStartTrackingTouch(slider: Slider) {
+                }
+
+                override fun onStopTrackingTouch(slider: Slider) {
+                    earthworkManager.updateDesignHeight(slider.value.toDouble())
+                }
+            }
+        )
+        binding.switchDesignSurface.setOnCheckedChangeListener { button, isChecked ->
+            showDesignHeight.value = isChecked
+        }
+        earthworkManager.setupOnMoveListener()
+        binding.switchSlopeResult.setOnCheckedChangeListener { _, isChecked ->
+            slopeResultVisible.value = isChecked
+        }
+        initData()
+    }
+
+    private val showDesignHeight = MutableStateFlow(false)
+    private val slopeResultVisible = MutableStateFlow(false)
+
+    @OptIn(ExperimentalUuidApi::class)
+    private fun initData() {
+        viewModel.points.onEach {
+            contoursManager.updatePoints(it)
+            contoursManager.updateHeightRange()
+            contoursManager.refresh()
+        }.launchIn(lifecycleScope)
+        contoursManager.gridModel.filterNotNull().onEach {
+            earthworkManager.updateGridModel(it)
+        }.launchIn(lifecycleScope)
+        earthworkManager.slopeDirection.onEach {
+            binding.slopeDirection.value = it.degrees.toFloat()
+        }.launchIn(lifecycleScope)
+        val slopeResultSourceId: String = Uuid.random().toString()
+        val slopeResultLayerId: String = Uuid.random().toString()
+        combine(
+            earthworkManager.slopeDirection,
+            earthworkManager.slopePercentage,
+            earthworkManager.baseHeightOffset,
+            contoursManager.gridModel,
+            showDesignHeight,
+            slopeResultVisible
+        ) {
+            Params6(
+                p1 = it[0] as Angle,
+                p2 = it[1] as Double,
+                p3 = it[2] as Double,
+                p4 = it[3] as? GridModel?,
+                p5 = it[4] as Boolean,
+                p6 = it[5] as Boolean
+            )
+        }.map { (slopeDirection, slopePercentage, baseHeightOffset, gridModel, showDesignHeight, slopeResultVisible) ->
+            if (!slopeResultVisible) {
+                mapView.mapboxMap.getStyle { style ->
+                    style.removeStyleLayer(slopeResultLayerId)
+                    style.removeStyleLayer("${slopeResultLayerId}-outline")
+                    style.removeStyleSource(slopeResultSourceId)
+                }
+            } else gridModel?.let { gridModel ->
+                val slopeResult: SlopeResult = SlopeCalculator.calculateSlope(
+                    grid = gridModel,
+                    slopeDirection = slopeDirection.degrees,
+                    slopePercentage = slopePercentage,
+                    baseHeightOffset = baseHeightOffset
+                )
+                mapView.displaySlopeResult(
+                    originalGrid = gridModel,
+                    slopeResult = slopeResult,
+                    sourceId = slopeResultSourceId,
+                    layerId = slopeResultLayerId,
+                    palette = contoursManager.simplePalette::palette,
+                    showDesignHeight = showDesignHeight
+                )
+            }
+        }.launchIn(lifecycleScope)
+    }
+}
+
+data class Params6<
+        out P1,
+        out P2,
+        out P3,
+        out P4,
+        out P5,
+        out P6,
+        >(
+    val p1: P1,
+    val p2: P2,
+    val p3: P3,
+    val p4: P4,
+    val p5: P5,
+    val p6: P6,
+)
+
+val home = GeoPoint(114.476060, 22.771073, 30.897)
+
+fun initGeoHelper(base: GeoPoint = home) {
+    val geoHelper = GeoHelper.getSharedInstance()
+    geoHelper.wgs84ToENU(
+        lon = base.longitude,
+        lat = base.latitude,
+        hgt = base.altitude
+    )
+}

android/src/main/java/com/icegps/geotools/MainViewModel.kt

@@ -0,0 +1,59 @@
+package com.icegps.geotools
+
+import android.app.Application
+import android.util.Log
+import androidx.lifecycle.AndroidViewModel
+import androidx.lifecycle.viewModelScope
+import com.icegps.common.helper.GeoHelper
+import com.icegps.math.geometry.Vector3D
+import com.icegps.geotools.ktx.toast
+import com.icegps.shared.SharedHttpClient
+import com.icegps.shared.SharedJson
+import com.icegps.shared.api.OpenElevation
+import com.icegps.shared.api.OpenElevationApi
+import com.icegps.shared.ktx.TAG
+import com.icegps.shared.model.GeoPoint
+import com.mapbox.geojson.Point
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.catch
+import kotlinx.coroutines.flow.debounce
+import kotlinx.coroutines.flow.filter
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.stateIn
+import kotlinx.coroutines.flow.update
+
+class MainViewModel(private val context: Application) : AndroidViewModel(context) {
+    private val geoHelper = GeoHelper.Companion.getSharedInstance()
+    private val openElevation: OpenElevationApi = OpenElevation(SharedHttpClient(SharedJson()))
+
+    private val _points = MutableStateFlow<List<Point>>(emptyList())
+    val points = _points.filter { it.size > 3 }.debounce(1000).map {
+        openElevation.lookup(it.map { GeoPoint(it.longitude(), it.latitude(), it.altitude()) })
+    }.catch {
+        Log.e(TAG, "高程请求失败", it)
+        context.toast("高程请求失败")
+    }.map {
+        it.map {
+            val enu = geoHelper.wgs84ToENU(lon = it.longitude, lat = it.latitude, hgt = it.altitude)
+            Vector3D(enu.x, enu.y, enu.z)
+        }
+    }.stateIn(
+        scope = viewModelScope,
+        started = SharingStarted.Companion.Eagerly,
+        initialValue = emptyList()
+    )
+
+    fun addPoint(point: Point) {
+        context.toast("${point.longitude()}, ${point.latitude()}")
+        _points.update {
+            it.toMutableList().apply {
+                add(point)
+            }
+        }
+    }
+
+    fun clearPoints() {
+        _points.value = emptyList()
+    }
+}

android/src/main/java/com/icegps/geotools/PolylineManager.kt

@@ -0,0 +1,121 @@
+package com.icegps.geotools
+
+import android.graphics.Color
+import com.icegps.math.geometry.Line3D
+import com.icegps.math.geometry.Vector3D
+import com.icegps.geotools.ktx.toMapboxPoint
+import com.mapbox.geojson.Feature
+import com.mapbox.geojson.FeatureCollection
+import com.mapbox.geojson.LineString
+import com.mapbox.maps.MapView
+import com.mapbox.maps.Style
+import com.mapbox.maps.extension.style.layers.addLayer
+import com.mapbox.maps.extension.style.layers.generated.lineLayer
+import com.mapbox.maps.extension.style.layers.properties.generated.LineCap
+import com.mapbox.maps.extension.style.layers.properties.generated.LineJoin
+import com.mapbox.maps.extension.style.sources.addSource
+import com.mapbox.maps.extension.style.sources.generated.geoJsonSource
+
+class PolylineManager(
+    private val mapView: MapView
+) {
+    private val sourceId: String = "polyline-source-id-0"
+    private val layerId: String = "polyline-layer-id-0"
+
+    fun update(
+        points: List<List<Vector3D>>
+    ) {
+        val lineStrings: List<List<Feature>> = points.map {
+            val lines = fromPoints(it, true)
+            lines.map {
+                LineString.fromLngLats(listOf(it.a.toMapboxPoint(), it.b.toMapboxPoint()))
+            }
+        }.map {
+            it.map { Feature.fromGeometry(it) }
+        }
+
+        mapView.mapboxMap.getStyle { style ->
+            setupLineLayer(
+                style = style,
+                sourceId = sourceId,
+                layerId = layerId,
+                features = lineStrings.flatten()
+            )
+        }
+    }
+
+    fun updateFeatures(
+        features: List<Feature>
+    ) {
+        mapView.mapboxMap.getStyle { style ->
+            setupLineLayer(
+                style = style,
+                sourceId = sourceId,
+                layerId = layerId,
+                features = features
+            )
+        }
+    }
+
+    private fun setupLineLayer(
+        style: Style,
+        sourceId: String,
+        layerId: String,
+        features: List<Feature>
+    ) {
+        style.removeStyleLayer(layerId)
+        style.removeStyleSource(sourceId)
+
+        val source = geoJsonSource(sourceId) {
+            featureCollection(FeatureCollection.fromFeatures(features))
+        }
+        style.addSource(source)
+
+        val layer = lineLayer(layerId, sourceId) {
+            lineColor(Color.RED)
+            lineWidth(2.0)
+            lineCap(LineCap.Companion.ROUND)
+            lineJoin(LineJoin.Companion.ROUND)
+            lineOpacity(0.8)
+        }
+        style.addLayer(layer)
+    }
+
+    fun clearContours() {
+        mapView.mapboxMap.getStyle { style ->
+            try {
+                style.removeStyleLayer(layerId)
+            } catch (_: Exception) {
+            }
+            try {
+                style.removeStyleSource(sourceId)
+            } catch (_: Exception) {
+            }
+        }
+    }
+}
+
+fun fromPoints(
+    points: List<Vector3D>,
+    closed: Boolean,
+) = if (points.isEmpty()) {
+    emptyList()
+} else {
+    if (!closed) {
+        (0 until points.size - 1).map {
+            Line3D(
+                points[it],
+                points[it + 1]
+            )
+        }
+    } else {
+        val d = (points.last() - points.first()).length
+        val usePoints = if (d > 1E-6) points else points.dropLast(1)
+        (usePoints.indices).map {
+            Line3D(
+                usePoints[it],
+                usePoints[(it + 1) % usePoints.size]
+            )
+        }
+    }
+}

android/src/main/java/com/icegps/geotools/RayCastingAlgorithm.kt

@@ -0,0 +1,44 @@
+package com.icegps.geotools
+
+import com.icegps.math.geometry.Vector2D
+import com.icegps.math.geometry.Vector3D
+import com.icegps.math.geometry.toVector2D
+
+/**
+ * @author tabidachinokaze
+ * @date 2025/11/26
+ */
+object RayCastingAlgorithm {
+    /**
+     * 使用射线法判断点是否在多边形内
+     * @param point 测试点
+     * @param polygon 多边形顶点列表
+     * @return true如果在多边形内
+     */
+    fun isPointInPolygon(point: Vector2D, polygon: List<Vector2D>): Boolean {
+        if (polygon.size < 3) return false
+
+        val x = point.x
+        val y = point.y
+        var inside = false
+
+        var j = polygon.size - 1
+        for (i in polygon.indices) {
+            val xi = polygon[i].x
+            val yi = polygon[i].y
+            val xj = polygon[j].x
+            val yj = polygon[j].y
+
+            val intersect = ((yi > y) != (yj > y)) && (x < (xj - xi) * (y - yi) / (yj - yi) + xi)
+
+            if (intersect) inside = !inside
+            j = i
+        }
+
+        return inside
+    }
+
+    fun isPointInPolygon(point: Vector3D, polygon: List<Vector3D>): Boolean {
+        return isPointInPolygon(point.toVector2D(), polygon.map { it.toVector2D() })
+    }
+}

android/src/main/java/com/icegps/geotools/SimplePalette.kt

@@ -0,0 +1,123 @@
+package com.icegps.geotools
+
+import android.util.Log
+
+/**
+ * @author tabidachinokaze
+ * @date 2025/11/25
+ */
+class SimplePalette(
+    private var range: ClosedFloatingPointRange<Double>
+) {
+    fun setRange(range: ClosedFloatingPointRange<Double>) {
+        this.range = range
+    }
+
+    private val colors: Map<Int, String>
+
+    init {
+        colors = generateTerrainColorMap()
+    }
+
+    fun palette(value: Double?): String {
+        if (value == null) return "#00000000"
+        val minH = range.start
+        val maxH = range.endInclusive
+        val normalized = ((value - minH) / (maxH - minH)).coerceIn(0.0, 1.0)
+        return colors[(normalized * 255).toInt()] ?: "#00000000"
+    }
+
+    fun palette1(value: Double?): String {
+        return if (value == null) "#00000000" else {
+            // 假设您已经知道高度范围，或者动态计算
+            val minH = range.start
+            val maxH = range.endInclusive
+            val normalized = ((value - minH) / (maxH - minH)).coerceIn(0.0, 1.0)
+            val alpha = (normalized * 255).toInt()
+            String.format("#%02X%02X%02X", alpha, 0, 0)
+        }.also {
+            Log.d("simplePalette", "$value -> $it")
+        }
+    }
+
+    fun generateGrayscaleColorMap2(): MutableMap<Int, String> {
+        val colorMap = mutableMapOf<Int, String>()
+
+        // 定义关键灰度点
+        val black = Color(0, 0, 0)       // 低地势 - 黑色
+        val darkGray = Color(64, 64, 64) // 过渡
+        val midGray = Color(128, 128, 128) // 中间
+        val lightGray = Color(192, 192, 192) // 过渡
+        val white = Color(255, 255, 255) // 高地势 - 白色
+
+        for (i in 0..255) {
+            val position = i / 255.0
+
+            val color = when {
+                position < 0.25 -> interpolateColor(black, darkGray, position / 0.25)
+                position < 0.5 -> interpolateColor(darkGray, midGray, (position - 0.25) / 0.25)
+                position < 0.75 -> interpolateColor(midGray, lightGray, (position - 0.5) / 0.25)
+                else -> interpolateColor(lightGray, white, (position - 0.75) / 0.25)
+            }
+            colorMap[i] = color.toHex()
+        }
+
+        return colorMap
+    }
+
+    fun generateGrayscaleColorMap(): MutableMap<Int, String> {
+        val colorMap = mutableMapOf<Int, String>()
+
+        for (i in 0..255) {
+            // 从黑色到白色的线性渐变
+            val grayValue = i
+            val color = Color(grayValue, grayValue, grayValue)
+            colorMap[i] = color.toHex()
+        }
+
+        return colorMap
+    }
+
+    fun generateTerrainColorMap(): MutableMap<Int, String> {
+        val colorMap = mutableMapOf<Int, String>()
+
+        // 定义关键颜色点
+        val blue = Color(0, 0, 255)    // 低地势 - 蓝色
+        val cyan = Color(0, 255, 255)  // 中间过渡
+        val green = Color(0, 255, 0)   // 中间过渡
+        val yellow = Color(255, 255, 0) // 中间过渡
+        val red = Color(255, 0, 0)     // 高地势 - 红色
+
+        for (i in 0..255) {
+            val position = i / 255.0
+
+            val color = when {
+                position < 0.25 -> interpolateColor(blue, cyan, position / 0.25)
+                position < 0.5 -> interpolateColor(cyan, green, (position - 0.25) / 0.25)
+                position < 0.75 -> interpolateColor(green, yellow, (position - 0.5) / 0.25)
+                else -> interpolateColor(yellow, red, (position - 0.75) / 0.25)
+            }
+            colorMap[i] = color.toHex()
+        }
+
+        return colorMap
+    }
+
+    fun interpolateColor(start: Color, end: Color, fraction: Double): Color {
+        val r = (start.red + (end.red - start.red) * fraction).toInt()
+        val g = (start.green + (end.green - start.green) * fraction).toInt()
+        val b = (start.blue + (end.blue - start.blue) * fraction).toInt()
+        return Color(r, g, b)
+    }
+
+    // Color类简化实现
+    class Color(val red: Int, val green: Int, val blue: Int) {
+        fun toArgb(): Int {
+            return (0xFF shl 24) or (red shl 16) or (green shl 8) or blue
+        }
+
+        fun toHex(): String {
+            return String.format("#%06X", toArgb() and 0xFFFFFF)
+        }
+    }
+}

android/src/main/java/com/icegps/geotools/catmullrom/CatmullRom.kt

@@ -0,0 +1,135 @@
+package com.icegps.geotools.catmullrom
+
+import com.icegps.math.geometry.Vector2D
+import com.icegps.geotools.marchingsquares.Segment2D
+import com.icegps.geotools.marchingsquares.ShapeContour
+import kotlin.math.min
+import kotlin.math.pow
+
+private const val almostZero = 0.00000001
+private const val almostOne = 0.99999999
+
+/**
+ * Creates a 2D Catmull-Rom spline curve.
+ *
+ * Can be represented as a segment drawn between [p1] and [p2],
+ * while [p0] and [p3] are used as control points.
+ *
+ * Under some circumstances alpha can have
+ * no perceptible effect, for example,
+ * when creating closed shapes with the vertices
+ * forming a regular 2D polygon.
+ *
+ * @param p0 The first control point.
+ * @param p1 The starting anchor point.
+ * @param p2 The ending anchor point.
+ * @param p3 The second control point.
+ * @param alpha The *tension* of the curve.
+ *      Use `0.0` for the uniform spline, `0.5` for the centripetal spline, `1.0` for the chordal spline.
+ */
+class CatmullRom2(val p0: Vector2D, val p1: Vector2D, val p2: Vector2D, val p3: Vector2D, val alpha: Double = 0.5) {
+    /** Value of t for p0. */
+    val t0: Double = 0.0
+
+    /** Value of t for p1. */
+    val t1: Double = calculateT(t0, p0, p1)
+
+    /** Value of t for p2. */
+    val t2: Double = calculateT(t1, p1, p2)
+
+    /** Value of t for p3. */
+    val t3: Double = calculateT(t2, p2, p3)
+
+    fun position(rt: Double): Vector2D {
+        val t = t1 + rt * (t2 - t1)
+        val a1 = p0 * ((t1 - t) / (t1 - t0)) + p1 * ((t - t0) / (t1 - t0))
+        val a2 = p1 * ((t2 - t) / (t2 - t1)) + p2 * ((t - t1) / (t2 - t1))
+        val a3 = p2 * ((t3 - t) / (t3 - t2)) + p3 * ((t - t2) / (t3 - t2))
+
+        val b1 = a1 * ((t2 - t) / (t2 - t0)) + a2 * ((t - t0) / (t2 - t0))
+        val b2 = a2 * ((t3 - t) / (t3 - t1)) + a3 * ((t - t1) / (t3 - t1))
+
+        val c = b1 * ((t2 - t) / (t2 - t1)) + b2 * ((t - t1) / (t2 - t1))
+        return c
+    }
+
+    private fun calculateT(t: Double, p0: Vector2D, p1: Vector2D): Double {
+        val a = (p1.x - p0.x).pow(2.0) + (p1.y - p0.y).pow(2.0)
+        val b = a.pow(0.5)
+        val c = b.pow(alpha)
+        return c + t
+    }
+}
+
+/**
+ * Calculates the 2D Catmull–Rom spline for a chain of points and returns the combined curve.
+ *
+ * For more details, see [CatmullRom2].
+ *
+ * @param points The [List] of 2D points where [CatmullRom2] is applied in groups of 4.
+ * @param alpha The *tension* of the curve.
+ *      Use `0.0` for the uniform spline, `0.5` for the centripetal spline, `1.0` for the chordal spline.
+ * @param loop Whether to connect the first and last point, such that it forms a closed shape.
+ */
+class CatmullRomChain2(points: List<Vector2D>, alpha: Double = 0.5, val loop: Boolean = false) {
+    val segments = if (!loop) {
+        val startPoints = points.take(2)
+        val endPoints = points.takeLast(2)
+        val mirrorStart =
+            startPoints.first() - (startPoints.last() - startPoints.first()).normalized
+        val mirrorEnd = endPoints.last() + (endPoints.last() - endPoints.first()).normalized
+
+        (listOf(mirrorStart) + points + listOf(mirrorEnd)).windowed(4, 1).map {
+            CatmullRom2(it[0], it[1], it[2], it[3], alpha)
+        }
+    } else {
+        val cleanPoints = if (loop && points.first().distanceTo(points.last()) <= 1.0E-6) {
+            points.dropLast(1)
+        } else {
+            points
+        }
+        (cleanPoints + cleanPoints.take(3)).windowed(4, 1).map {
+            CatmullRom2(it[0], it[1], it[2], it[3], alpha)
+        }
+    }
+
+    fun positions(steps: Int = segments.size * 4): List<Vector2D> {
+        return (0..steps).map {
+            position(it.toDouble() / steps)
+        }
+    }
+
+    fun position(rt: Double): Vector2D {
+        val st = if (loop) rt.mod(1.0) else rt.coerceIn(0.0, 1.0)
+        val segmentIndex = (min(almostOne, st) * segments.size).toInt()
+        val t = (min(almostOne, st) * segments.size) - segmentIndex
+        return segments[segmentIndex].position(t)
+    }
+}
+
+fun List<Vector2D>.catmullRom(alpha: Double = 0.5, closed: Boolean) = CatmullRomChain2(this, alpha, closed)
+
+/** Converts spline to a [Segment]. */
+fun CatmullRom2.toSegment(): Segment2D {
+    val d1a2 = (p1 - p0).length.pow(2 * alpha)
+    val d2a2 = (p2 - p1).length.pow(2 * alpha)
+    val d3a2 = (p3 - p2).length.pow(2 * alpha)
+    val d1a = (p1 - p0).length.pow(alpha)
+    val d2a = (p2 - p1).length.pow(alpha)
+    val d3a = (p3 - p2).length.pow(alpha)
+
+    val b0 = p1
+    val b1 = (p2 * d1a2 - p0 * d2a2 + p1 * (2 * d1a2 + 3 * d1a * d2a + d2a2)) / (3 * d1a * (d1a + d2a))
+    val b2 = (p1 * d3a2 - p3 * d2a2 + p2 * (2 * d3a2 + 3 * d3a * d2a + d2a2)) / (3 * d3a * (d3a + d2a))
+    val b3 = p2
+
+    return Segment2D(b0, b1, b2, b3)
+}
+
+
+/**
+ * Converts chain to a [ShapeContour].
+ */
+@Suppress("unused")
+fun CatmullRomChain2.toContour(): ShapeContour =
+    ShapeContour(segments.map { it.toSegment() }, this.loop)

android/src/main/java/com/icegps/geotools/color/ColorRGBa.kt

@@ -0,0 +1,427 @@
+package com.icegps.geotools.color
+
+import com.icegps.math.geometry.Vector3D
+import com.icegps.math.geometry.Vector4D
+import kotlinx.serialization.Serializable
+import kotlin.math.pow
+
+@Serializable
+enum class Linearity(val certainty: Int) {
+    /**
+     * Represents a linear color space.
+     *
+     * LINEAR typically signifies that the values in the color space are in a linear relationship,
+     * meaning there is no gamma correction or transformation applied to the data.
+     */
+    LINEAR(1),
+
+    /**
+     * Represents a standard RGB (sRGB) color space.
+     *
+     * SRGB typically refers to a non-linear color space with gamma correction applied,
+     * designed for consistent color representation across devices.
+     */
+    SRGB(1),
+    ;
+
+    fun leastCertain(other: Linearity): Linearity {
+        return if (this.certainty <= other.certainty) {
+            this
+        } else {
+            other
+        }
+    }
+
+    fun isEquivalent(other: Linearity): Boolean {
+        return this == other
+    }
+
+}
+
+/**
+ * Represents a color in the RGBA color space. Each component, including red, green, blue, and alpha (opacity),
+ * is represented as a `Double` in the range `[0.0, 1.0]`. The color can be defined in either linear or sRGB space,
+ * determined by the `linearity` property.
+ *
+ * This class provides a wide variety of utility functions for manipulating and converting colors, such as shading,
+ * opacity adjustment, and format transformations. It also includes methods for parsing colors from hexadecimal
+ * notation or vectors.
+ *
+ * @property r Red component of the color as a value between `0.0` and `1.0`.
+ * @property g Green component of the color as a value between `0.0` and `1.0`.
+ * @property b Blue component of the color as a value between `0.0` and `1.0`.
+ * @property alpha Alpha (opacity) component of the color as a value between `0.0` and `1.0`. Defaults to `1.0`.
+ * @property linearity Indicates whether the color is defined in linear or sRGB space. Defaults to [Linearity.LINEAR].
+ */
+@Serializable
+@Suppress("EqualsOrHashCode") // generated equals() is ok, only hashCode() needs to be overridden
+data class ColorRGBa(
+    val r: Double,
+    val g: Double,
+    val b: Double,
+    val alpha: Double = 1.0,
+    val linearity: Linearity = Linearity.LINEAR
+) {
+
+    enum class Component {
+        R,
+        G,
+        B
+    }
+
+    companion object {
+        /**
+         * Calculates a color from hexadecimal value. For values with transparency
+         * use the [String] variant of this function.
+         */
+        fun fromHex(hex: Int): ColorRGBa {
+            val r = hex and (0xff0000) shr 16
+            val g = hex and (0x00ff00) shr 8
+            val b = hex and (0x0000ff)
+            return ColorRGBa(r / 255.0, g / 255.0, b / 255.0, 1.0, Linearity.SRGB)
+        }
+
+        /**
+         * Calculates a color from hexadecimal notation, like in CSS.
+         *
+         * Supports the following formats
+         * * `RGB`
+         * * `RGBA`
+         * * `RRGGBB`
+         * * `RRGGBBAA`
+         *
+         * where every character is a valid hex digit between `0..f` (case-insensitive).
+         * Supports leading "#" or "0x".
+         */
+        fun fromHex(hex: String): ColorRGBa {
+            val pos = when {
+                hex.startsWith("#") -> 1
+                hex.startsWith("0x") -> 2
+                else -> 0
+            }
+
+            fun fromHex1(str: String, pos: Int): Double {
+                return 17 * str[pos].digitToInt(16) / 255.0
+            }
+
+            fun fromHex2(str: String, pos: Int): Double {
+                return (16 * str[pos].digitToInt(16) + str[pos + 1].digitToInt(16)) / 255.0
+            }
+            return when (hex.length - pos) {
+                3 -> ColorRGBa(fromHex1(hex, pos), fromHex1(hex, pos + 1), fromHex1(hex, pos + 2), 1.0, Linearity.SRGB)
+                4 -> ColorRGBa(
+                    fromHex1(hex, pos),
+                    fromHex1(hex, pos + 1),
+                    fromHex1(hex, pos + 2),
+                    fromHex1(hex, pos + 3),
+                    Linearity.SRGB
+                )
+
+                6 -> ColorRGBa(fromHex2(hex, pos), fromHex2(hex, pos + 2), fromHex2(hex, pos + 4), 1.0, Linearity.SRGB)
+                8 -> ColorRGBa(
+                    fromHex2(hex, pos),
+                    fromHex2(hex, pos + 2),
+                    fromHex2(hex, pos + 4),
+                    fromHex2(hex, pos + 6),
+                    Linearity.SRGB
+                )
+
+                else -> throw IllegalArgumentException("Invalid hex length/format for '$hex'")
+            }
+        }
+
+        /** @suppress */
+        val PINK = fromHex(0xffc0cb)
+
+        /** @suppress */
+        val BLACK = ColorRGBa(0.0, 0.0, 0.0, 1.0, Linearity.SRGB)
+
+        /** @suppress */
+        val WHITE = ColorRGBa(1.0, 1.0, 1.0, 1.0, Linearity.SRGB)
+
+        /** @suppress */
+        val RED = ColorRGBa(1.0, 0.0, 0.0, 1.0, Linearity.SRGB)
+
+        /** @suppress */
+        val BLUE = ColorRGBa(0.0, 0.0, 1.0, 1.0, Linearity.SRGB)
+
+        /** @suppress */
+        val GREEN = ColorRGBa(0.0, 1.0, 0.0, 1.0, Linearity.SRGB)
+
+        /** @suppress */
+        val YELLOW = ColorRGBa(1.0, 1.0, 0.0, 1.0, Linearity.SRGB)
+
+        /** @suppress */
+        val CYAN = ColorRGBa(0.0, 1.0, 1.0, 1.0, Linearity.SRGB)
+
+        /** @suppress */
+        val MAGENTA = ColorRGBa(1.0, 0.0, 1.0, 1.0, Linearity.SRGB)
+
+        /** @suppress */
+        val GRAY = ColorRGBa(0.5, 0.5, 0.5, 1.0, Linearity.SRGB)
+
+        /** @suppress */
+        val TRANSPARENT = ColorRGBa(0.0, 0.0, 0.0, 0.0, Linearity.LINEAR)
+
+        /**
+         * Create a ColorRGBa object from a [Vector3]
+         * @param vector input vector, `[x, y, z]` is mapped to `[r, g, b]`
+         * @param alpha optional alpha value, default is 1.0
+         */
+        fun fromVector(vector: Vector3D, alpha: Double = 1.0, linearity: Linearity = Linearity.LINEAR): ColorRGBa {
+            return ColorRGBa(vector.x, vector.y, vector.z, alpha, linearity)
+        }
+
+
+        /**
+         * Create a ColorRGBa object from a [Vector4]
+         * @param vector input vector, `[x, y, z, w]` is mapped to `[r, g, b, a]`
+         */
+        fun fromVector(vector: Vector4D, linearity: Linearity = Linearity.LINEAR): ColorRGBa {
+            return ColorRGBa(vector.x, vector.y, vector.z, vector.w, linearity)
+        }
+    }
+
+    @Deprecated("Legacy alpha parameter name", ReplaceWith("alpha"))
+    val a = alpha
+
+    /**
+     * Creates a copy of color with adjusted opacity
+     * @param factor a scaling factor used for the opacity
+     * @return A [ColorRGBa] with scaled opacity
+     * @see shade
+     */
+    fun opacify(factor: Double): ColorRGBa = ColorRGBa(r, g, b, alpha * factor, linearity)
+
+    /**
+     * Creates a copy of color with adjusted color
+     * @param factor a scaling factor used for the opacity
+     * @return A [ColorRGBa] with scaled colors
+     * @see opacify
+     */
+    fun shade(factor: Double): ColorRGBa = ColorRGBa(r * factor, g * factor, b * factor, alpha, linearity)
+
+    /**
+     * Copy of the color with all of its fields clamped to `[0, 1]`
+     */
+
+    @Deprecated("Use clip() instead", replaceWith = ReplaceWith("clip()"))
+    val saturated: ColorRGBa
+        get() = clip()
+
+    /**
+     * Copy of the color with all of its fields clamped to `[0, 1]`
+     */
+    fun clip(): ColorRGBa = copy(
+        r = r.coerceIn(0.0..1.0),
+        g = g.coerceIn(0.0..1.0),
+        b = b.coerceIn(0.0..1.0),
+        alpha = alpha.coerceIn(0.0..1.0)
+    )
+
+
+    /**
+     * Returns a new instance of [ColorRGBa] where the red, green, and blue components
+     * are multiplied by the alpha value of the original color. The alpha value and linearity
+     * remain unchanged.
+     *
+     * This computed property is commonly used for adjusting the color intensity based
+     * on its transparency.
+     */
+    val alphaMultiplied: ColorRGBa
+        get() = ColorRGBa(r * alpha, g * alpha, b * alpha, alpha, linearity)
+
+    /**
+     * The minimum value over `r`, `g`, `b`
+     * @see maxValue
+     */
+    val minValue get() = r.coerceAtMost(g).coerceAtMost(b)
+
+    /**
+     * The maximum value over `r`, `g`, `b`
+     * @see minValue
+     */
+    val maxValue get() = r.coerceAtLeast(g).coerceAtLeast(b)
+
+    /**
+     * calculate luminance value
+     * luminance value is according to <a>https://www.w3.org/TR/2008/REC-WCAG20-20081211/#relativeluminancedef</a>
+     */
+    val luminance: Double
+        get() = when (linearity) {
+            Linearity.SRGB -> toLinear().luminance
+            else -> 0.2126 * r + 0.7152 * g + 0.0722 * b
+        }
+
+    /**
+     * Converts this color to the specified linearity.
+     *
+     * @param linearity The target linearity to which the color should be converted.
+     *                  Supported values are [Linearity.SRGB] and [Linearity.LINEAR].
+     * @return A [ColorRGBa] instance in the specified linearity.
+     */
+    fun toLinearity(linearity: Linearity): ColorRGBa {
+        return when (linearity) {
+            Linearity.SRGB -> toSRGB()
+            Linearity.LINEAR -> toLinear()
+        }
+    }
+
+    /**
+     * calculate the contrast value between this color and the given color
+     * contrast value is accordingo to <a>// see http://www.w3.org/TR/2008/REC-WCAG20-20081211/#contrast-ratiodef</a>
+     */
+    fun getContrastRatio(other: ColorRGBa): Double {
+        val l1 = luminance
+        val l2 = other.luminance
+        return if (l1 > l2) (l1 + 0.05) / (l2 + 0.05) else (l2 + 0.05) / (l1 + 0.05)
+    }
+
+    fun toLinear(): ColorRGBa {
+        fun t(x: Double): Double {
+            return if (x <= 0.04045) x / 12.92 else ((x + 0.055) / (1 + 0.055)).pow(2.4)
+        }
+        return when (linearity) {
+            Linearity.SRGB -> ColorRGBa(t(r), t(g), t(b), alpha, Linearity.LINEAR)
+            else -> this
+        }
+    }
+
+    /**
+     * Convert to SRGB
+     * @see toLinear
+     */
+    fun toSRGB(): ColorRGBa {
+        fun t(x: Double): Double {
+            return if (x <= 0.0031308) 12.92 * x else (1 + 0.055) * x.pow(1.0 / 2.4) - 0.055
+        }
+        return when (linearity) {
+            Linearity.LINEAR -> ColorRGBa(t(r), t(g), t(b), alpha, Linearity.SRGB)
+            else -> this
+        }
+    }
+
+    fun toRGBa(): ColorRGBa = this
+
+    // This is here because the default hashing of enums on the JVM is not stable.
+    override fun hashCode(): Int {
+        var result = r.hashCode()
+        result = 31 * result + g.hashCode()
+        result = 31 * result + b.hashCode()
+        result = 31 * result + alpha.hashCode()
+        // here we overcome the unstable hash by using the ordinal value
+        result = 31 * result + linearity.ordinal.hashCode()
+        return result
+    }
+
+    fun plus(right: ColorRGBa) = copy(
+        r = r + right.r,
+        g = g + right.g,
+        b = b + right.b,
+        alpha = alpha + right.alpha
+    )
+
+    fun minus(right: ColorRGBa) = copy(
+        r = r - right.r,
+        g = g - right.g,
+        b = b - right.b,
+        alpha = alpha - right.alpha
+    )
+
+    fun times(scale: Double) = copy(r = r * scale, g = g * scale, b = b * scale, alpha = alpha * scale)
+
+    fun mix(other: ColorRGBa, factor: Double): ColorRGBa {
+        return mix(this, other, factor)
+    }
+
+    fun toVector4(): Vector4D = Vector4D(r, g, b, alpha)
+
+    /**
+     * Retrieves the color's RGBA component value based on the specified index:
+     * [index] should be 0 for red, 1 for green, 2 for blue, 3 for alpha.
+     * Other index values throw an [IndexOutOfBoundsException].
+     */
+    operator fun get(index: Int) = when (index) {
+        0 -> r
+        1 -> g
+        2 -> b
+        3 -> alpha
+        else -> throw IllegalArgumentException("unsupported index")
+    }
+}
+
+/**
+ * Weighted mix between two colors in the generic RGB color space.
+ * @param x the weighting of colors, a value 0.0 is equivalent to [left],
+ * 1.0 is equivalent to [right] and at 0.5 both colors contribute to the result equally
+ * @return a mix of [left] and [right] weighted by [x]
+ */
+fun mix(left: ColorRGBa, right: ColorRGBa, x: Double): ColorRGBa {
+    val sx = x.coerceIn(0.0, 1.0)
+
+    if (left.linearity.isEquivalent(right.linearity)) {
+        return ColorRGBa(
+            (1.0 - sx) * left.r + sx * right.r,
+            (1.0 - sx) * left.g + sx * right.g,
+            (1.0 - sx) * left.b + sx * right.b,
+            (1.0 - sx) * left.alpha + sx * right.alpha,
+            linearity = left.linearity.leastCertain(right.linearity)
+        )
+    } else {
+        return when (right.linearity) {
+            Linearity.LINEAR -> {
+                mix(left.toLinear(), right.toLinear(), x)
+            }
+
+            Linearity.SRGB -> {
+                mix(left.toSRGB(), right.toSRGB(), x)
+            }
+        }
+    }
+}
+
+/**
+ * Shorthand for calling [ColorRGBa].
+ * Specify only one value to obtain a shade of gray.
+ * @param r red in `[0,1]`
+ * @param g green in `[0,1]`
+ * @param b blue in `[0,1]`
+ * @param a alpha in `[0,1]`, defaults to `1.0`
+ */
+fun rgb(r: Double, g: Double, b: Double, a: Double = 1.0) = ColorRGBa(r, g, b, a, linearity = Linearity.LINEAR)
+
+/**
+ * Shorthand for calling [ColorRGBa].
+ * @param gray shade of gray in `[0,1]`
+ * @param a alpha in `[0,1]`, defaults to `1.0`
+ */
+fun rgb(gray: Double, a: Double = 1.0) = ColorRGBa(gray, gray, gray, a, linearity = Linearity.LINEAR)
+
+/**
+ * Create a color in RGBa space
+ * This function is a shorthand for using the ColorRGBa constructor
+ * @param r red in `[0,1]`
+ * @param g green in `[0,1]`
+ * @param b blue in `[0,1]`
+ * @param a alpha in `[0,1]`
+ */
+@Deprecated("Use rgb(r, g, b, a)", ReplaceWith("rgb(r, g, b, a)"), DeprecationLevel.WARNING)
+fun rgba(r: Double, g: Double, b: Double, a: Double) = ColorRGBa(r, g, b, a, linearity = Linearity.LINEAR)
+
+/**
+ * Shorthand for calling [ColorRGBa.fromHex].
+ * Creates a [ColorRGBa] with [Linearity.SRGB] from a hex string.
+ * @param hex string encoded hex value, for example `"ffc0cd"`
+ */
+fun rgb(hex: String) = ColorRGBa.fromHex(hex)
+
+/**
+ * Converts RGB integer color values into a ColorRGBa object with sRGB linearity.
+ *
+ * @param red The red component of the color, in the range 0-255.
+ * @param green The green component of the color, in the range 0-255.
+ * @param blue The blue component of the color, in the range 0-255.
+ * @param alpha The alpha (transparency) component of the color, in the range 0-255. Default value is 255 (fully opaque).
+ */
+fun rgb(red: Int, green: Int, blue: Int, alpha: Int = 255) =
+    ColorRGBa(red / 255.0, green / 255.0, blue / 255.0, alpha / 255.0, Linearity.SRGB)

android/src/main/java/com/icegps/geotools/ktx/ColorRGBa.kt

@@ -0,0 +1,23 @@
+package com.icegps.geotools.ktx
+
+import com.icegps.geotools.color.ColorRGBa
+
+/**
+ * @author tabidachinokaze
+ * @date 2025/11/25
+ */
+fun ColorRGBa.toColorInt(): Int {
+    val clampedR = r.coerceIn(0.0, 1.0)
+    val clampedG = g.coerceIn(0.0, 1.0)
+    val clampedB = b.coerceIn(0.0, 1.0)
+    val clampedAlpha = alpha.coerceIn(0.0, 1.0)
+
+    return ((clampedAlpha * 255).toInt() shl 24) or
+            ((clampedR * 255).toInt() shl 16) or
+            ((clampedG * 255).toInt() shl 8) or
+            ((clampedB * 255).toInt())
+}
+
+fun ColorRGBa.toColorHex(): String {
+    return String.format("#%06X", 0xFFFFFF and toColorInt())
+}

android/src/main/java/com/icegps/geotools/ktx/Context.kt

@@ -0,0 +1,12 @@
+package com.icegps.geotools.ktx
+
+import android.content.Context
+import android.widget.Toast
+
+/**
+ * @author tabidachinokaze
+ * @date 2025/11/25
+ */
+fun Context.toast(text: String, duration: Int = Toast.LENGTH_SHORT) {
+    Toast.makeText(this, text, duration).show()
+}

android/src/main/java/com/icegps/geotools/ktx/Vector2D.kt

@@ -0,0 +1,24 @@
+package com.icegps.geotools.ktx
+
+import com.icegps.common.helper.GeoHelper
+import com.icegps.math.geometry.Vector2D
+import com.mapbox.geojson.Point
+
+/**
+ * @author tabidachinokaze
+ * @date 2025/11/26
+ */
+fun Vector2D.toMapboxPoint(): Point {
+    val geoHelper = GeoHelper.getSharedInstance()
+    val wgs84 = geoHelper.enuToWGS84Object(GeoHelper.ENU(x = x, y = y))
+    return Point.fromLngLat(wgs84.lon, wgs84.lat)
+}
+
+/**
+ * Interpolates between the current vector and the given vector `o` by the specified mixing factor.
+ *
+ * @param o The target vector to interpolate towards.
+ * @param mix A mixing factor between 0 and 1 where `0` results in the current vector and `1` results in the vector `o`.
+ * @return A new vector that is the result of the interpolation.
+ */
+fun Vector2D.mix(o: Vector2D, mix: Double): Vector2D = this * (1 - mix) + o * mix

android/src/main/java/com/icegps/geotools/ktx/Vector3D.kt

@@ -0,0 +1,32 @@
+package com.icegps.geotools.ktx
+
+import com.icegps.common.helper.GeoHelper
+import com.icegps.math.geometry.Rectangle
+import com.icegps.math.geometry.Vector3D
+import com.mapbox.geojson.Point
+
+fun Vector3D.niceStr(): String {
+    return "[$x, $y, $z]".format(this)
+}
+
+fun List<Vector3D>.niceStr(): String {
+    return joinToString(", ", "[", "]") {
+        it.niceStr()
+    }
+}
+
+fun Vector3D.toMapboxPoint(): Point {
+    val geoHelper = GeoHelper.getSharedInstance()
+    return geoHelper.enuToWGS84Object(GeoHelper.ENU(x, y, z)).run {
+        Point.fromLngLat(lon, lat, hgt)
+    }
+}
+
+val List<Vector3D>.area: Rectangle
+    get() {
+        val minX = minOf { it.x }
+        val maxX = maxOf { it.x }
+        val minY = minOf { it.y }
+        val maxY = maxOf { it.y }
+        return Rectangle(x = minX, y = minY, width = maxX - minX, height = maxY - minY)
+    }

android/src/main/java/com/icegps/geotools/marchingsquares/MarchingSquares.kt

@@ -0,0 +1,219 @@
+package com.icegps.geotools.marchingsquares
+
+import com.icegps.math.geometry.Rectangle
+import com.icegps.math.geometry.Vector2D
+import com.icegps.math.geometry.Vector2I
+import com.icegps.geotools.ktx.mix
+import kotlin.math.max
+import kotlin.math.min
+
+private const val closeEpsilon = 1E-6
+
+data class Segment2D(
+    val start: Vector2D,
+    val control: List<Vector2D>,
+    val end: Vector2D,
+    val corner: Boolean = false
+)
+
+fun Segment2D(start: Vector2D, end: Vector2D, corner: Boolean = true) =
+    Segment2D(start, emptyList(), end, corner)
+
+fun Segment2D(start: Vector2D, c0: Vector2D, c1: Vector2D, end: Vector2D, corner: Boolean = true) =
+    Segment2D(start, listOf(c0, c1), end, corner)
+
+data class ShapeContour(
+    val segments: List<Segment2D>,
+    val closed: Boolean,
+) {
+    companion object {
+        val EMPTY = ShapeContour(
+            segments = emptyList(),
+            closed = false,
+        )
+
+        /**
+         * Creates a ShapeContour from a list of points, specifying whether the contour is closed and its y-axis polarity.
+         *
+         * @param points A list of points (Vector2) defining the vertices of the contour.
+         * @param closed Boolean indicating whether the contour should be closed (forms a loop).
+         * @return A ShapeContour object representing the resulting contour.
+         */
+        fun fromPoints(
+            points: List<Vector2D>,
+            closed: Boolean,
+        ): ShapeContour = if (points.isEmpty()) {
+            EMPTY
+        } else {
+            if (!closed) {
+                ShapeContour((0 until points.size - 1).map {
+                    Segment2D(
+                        points[it],
+                        points[it + 1]
+                    )
+                }, false)
+            } else {
+                val d = (points.last() - points.first()).lengthSquared
+                val usePoints = if (d > closeEpsilon) points else points.dropLast(1)
+                ShapeContour((usePoints.indices).map {
+                    Segment2D(
+                        usePoints[it],
+                        usePoints[(it + 1) % usePoints.size]
+                    )
+                }, true)
+            }
+        }
+    }
+}
+
+data class LineSegment(val start: Vector2D, val end: Vector2D)
+
+/**
+ * Find contours for a function [f] using the marching squares algorithm. A contour is found when f(x) crosses zero.
+ * @param f the function
+ * @param area a rectangular area in which the function should be evaluated
+ * @param cellSize the size of the cells, smaller size gives higher resolution
+ * @param useInterpolation intersection points will be interpolated if true, default true
+ * @return a list of [ShapeContour] instances
+ */
+fun findContours(
+    f: (Vector2D) -> Double,
+    area: Rectangle,
+    cellSize: Double,
+    useInterpolation: Boolean = true
+): List<ShapeContour> {
+    val segments = mutableListOf<LineSegment>()
+    val values = mutableMapOf<Vector2I, Double>()
+    val segmentsMap = mutableMapOf<Vector2D, MutableList<LineSegment>>()
+
+    for (y in 0 until (area.height / cellSize).toInt()) {
+        for (x in 0 until (area.width / cellSize).toInt()) {
+            values[Vector2I(x, y)] = f(Vector2D(x * cellSize + area.x, y * cellSize + area.y))
+        }
+    }
+
+    val zero = 0.0
+    for (y in 0 until (area.height / cellSize).toInt()) {
+        for (x in 0 until (area.width / cellSize).toInt()) {
+
+            // Here we check if we are at a right or top border. This is to ensure we create closed contours
+            // later on in the process.
+            val v00 = if (x == 0 || y == 0) zero else (values[Vector2I(x, y)] ?: zero)
+            val v10 = if (y == 0) zero else (values[Vector2I(x + 1, y)] ?: zero)
+            val v01 = if (x == 0) zero else (values[Vector2I(x, y + 1)] ?: zero)
+            val v11 = (values[Vector2I(x + 1, y + 1)] ?: zero)
+
+            val p00 = Vector2D(x.toDouble(), y.toDouble()) * cellSize + area.topLeft
+            val p10 = Vector2D((x + 1).toDouble(), y.toDouble()) * cellSize + area.topLeft
+            val p01 = Vector2D(x.toDouble(), (y + 1).toDouble()) * cellSize + area.topLeft
+            val p11 = Vector2D((x + 1).toDouble(), (y + 1).toDouble()) * cellSize + area.topLeft
+
+            val index = (if (v00 >= 0.0) 1 else 0) +
+                    (if (v10 >= 0.0) 2 else 0) +
+                    (if (v01 >= 0.0) 4 else 0) +
+                    (if (v11 >= 0.0) 8 else 0)
+
+            fun blend(v1: Double, v2: Double): Double {
+                if (useInterpolation) {
+                    require(!v1.isNaN() && !v2.isNaN()) {
+                        "Input values v1=$v1 or v2=$v2 are NaN, which is not allowed."
+                    }
+                    val f1 = min(v1, v2)
+                    val f2 = max(v1, v2)
+                    val v = (-f1) / (f2 - f1)
+
+                    require(v == v && v in 0.0..1.0) {
+                        "Invalid value calculated during interpolation: v=$v"
+                    }
+
+                    return if (f1 == v1) {
+                        v
+                    } else {
+                        1.0 - v
+                    }
+                } else {
+                    return 0.5
+                }
+            }
+
+            fun emitLine(
+                p00: Vector2D, p01: Vector2D, v00: Double, v01: Double,
+                p10: Vector2D, p11: Vector2D, v10: Double, v11: Double
+            ) {
+                val r0 = blend(v00, v01)
+                val r1 = blend(v10, v11)
+
+                val v0 = p00.mix(p01, r0)
+                val v1 = p10.mix(p11, r1)
+                val l0 = LineSegment(v0, v1)
+                segmentsMap.getOrPut(v1) { mutableListOf() }.add(l0)
+                segmentsMap.getOrPut(v0) { mutableListOf() }.add(l0)
+                segments.add(l0)
+            }
+
+            when (index) {
+                0, 15 -> {}
+                1, 15 xor 1 -> {
+                    emitLine(p00, p01, v00, v01, p00, p10, v00, v10)
+                }
+
+                2, 15 xor 2 -> {
+                    emitLine(p00, p10, v00, v10, p10, p11, v10, v11)
+                }
+
+                3, 15 xor 3 -> {
+                    emitLine(p00, p01, v00, v01, p10, p11, v10, v11)
+                }
+
+                4, 15 xor 4 -> {
+                    emitLine(p00, p01, v00, v01, p01, p11, v01, v11)
+                }
+
+                5, 15 xor 5 -> {
+                    emitLine(p00, p10, v00, v10, p01, p11, v01, v11)
+                }
+
+                6, 15 xor 6 -> {
+                    emitLine(p00, p01, v00, v01, p00, p10, v00, v10)
+                    emitLine(p01, p11, v01, v11, p10, p11, v10, v11)
+                }
+
+                7, 15 xor 7 -> {
+                    emitLine(p01, p11, v01, v11, p10, p11, v10, v11)
+                }
+            }
+        }
+    }
+
+    val processedSegments = mutableSetOf<LineSegment>()
+    val contours = mutableListOf<ShapeContour>()
+    for (segment in segments) {
+        if (segment in processedSegments) {
+            continue
+        } else {
+            val collected = mutableListOf<Vector2D>()
+            var current: LineSegment? = segment
+            var closed = true
+            var lastVertex = Vector2D.INFINITY
+            do {
+                current!!
+                if (lastVertex.squaredDistanceTo(current.start) > 1E-5) {
+                    collected.add(current.start)
+                }
+                lastVertex = current.start
+                processedSegments.add(current)
+                if (segmentsMap[current.start]!!.size < 2) {
+                    closed = false
+                }
+                val hold = current
+                current = segmentsMap[current.start]?.firstOrNull { it !in processedSegments }
+                if (current == null) {
+                    current = segmentsMap[hold.end]?.firstOrNull { it !in processedSegments }
+                }
+            } while (current != segment && current != null)
+
+            contours.add(ShapeContour.fromPoints(collected, closed = closed))
+        }
+    }
+    return contours
+}

android/src/main/res/drawable/ic_launcher_background.xml

@@ -0,0 +1,170 @@
+<?xml version="1.0" encoding="utf-8"?>
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportWidth="108"
+    android:viewportHeight="108">
+    <path
+        android:fillColor="#3DDC84"
+        android:pathData="M0,0h108v108h-108z" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M9,0L9,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,0L19,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M29,0L29,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M39,0L39,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M49,0L49,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M59,0L59,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M69,0L69,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M79,0L79,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M89,0L89,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M99,0L99,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,9L108,9"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,19L108,19"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,29L108,29"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,39L108,39"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,49L108,49"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,59L108,59"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,69L108,69"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,79L108,79"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,89L108,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,99L108,99"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,29L89,29"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,39L89,39"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,49L89,49"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,59L89,59"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,69L89,69"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,79L89,79"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M29,19L29,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M39,19L39,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M49,19L49,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M59,19L59,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M69,19L69,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M79,19L79,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+</vector>

android/src/main/res/drawable/ic_launcher_foreground.xml

@@ -0,0 +1,30 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:aapt="http://schemas.android.com/aapt"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportWidth="108"
+    android:viewportHeight="108">
+    <path android:pathData="M31,63.928c0,0 6.4,-11 12.1,-13.1c7.2,-2.6 26,-1.4 26,-1.4l38.1,38.1L107,108.928l-32,-1L31,63.928z">
+        <aapt:attr name="android:fillColor">
+            <gradient
+                android:endX="85.84757"
+                android:endY="92.4963"
+                android:startX="42.9492"
+                android:startY="49.59793"
+                android:type="linear">
+                <item
+                    android:color="#44000000"
+                    android:offset="0.0" />
+                <item
+                    android:color="#00000000"
+                    android:offset="1.0" />
+            </gradient>
+        </aapt:attr>
+    </path>
+    <path
+        android:fillColor="#FFFFFF"
+        android:fillType="nonZero"
+        android:pathData="M65.3,45.828l3.8,-6.6c0.2,-0.4 0.1,-0.9 -0.3,-1.1c-0.4,-0.2 -0.9,-0.1 -1.1,0.3l-3.9,6.7c-6.3,-2.8 -13.4,-2.8 -19.7,0l-3.9,-6.7c-0.2,-0.4 -0.7,-0.5 -1.1,-0.3C38.8,38.328 38.7,38.828 38.9,39.228l3.8,6.6C36.2,49.428 31.7,56.028 31,63.928h46C76.3,56.028 71.8,49.428 65.3,45.828zM43.4,57.328c-0.8,0 -1.5,-0.5 -1.8,-1.2c-0.3,-0.7 -0.1,-1.5 0.4,-2.1c0.5,-0.5 1.4,-0.7 2.1,-0.4c0.7,0.3 1.2,1 1.2,1.8C45.3,56.528 44.5,57.328 43.4,57.328L43.4,57.328zM64.6,57.328c-0.8,0 -1.5,-0.5 -1.8,-1.2s-0.1,-1.5 0.4,-2.1c0.5,-0.5 1.4,-0.7 2.1,-0.4c0.7,0.3 1.2,1 1.2,1.8C66.5,56.528 65.6,57.328 64.6,57.328L64.6,57.328z"
+        android:strokeWidth="1"
+        android:strokeColor="#00000000" />
+</vector>

android/src/main/res/layout-port/activity_main.xml

@@ -0,0 +1,190 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:id="@+id/main"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical"
+    tools:context=".MainActivity">
+
+    <com.mapbox.maps.MapView
+        android:id="@+id/map_view"
+        android:layout_width="match_parent"
+        android:layout_height="0dp"
+        android:layout_weight="3" />
+
+    <ScrollView
+        android:layout_width="match_parent"
+        android:layout_height="0dp"
+        android:layout_weight="1">
+
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:orientation="vertical">
+
+            <com.google.android.material.slider.Slider
+                android:id="@+id/slider_target_height"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:value="0"
+                android:valueFrom="0"
+                android:valueTo="100" />
+
+            <LinearLayout
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:gravity="center_vertical"
+                android:orientation="horizontal">
+
+                <TextView
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content"
+                    android:text="栅格大小：" />
+
+                <com.google.android.material.slider.Slider
+                    android:id="@+id/cell_size"
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_weight="1"
+                    android:value="1"
+                    android:valueFrom="1"
+                    android:valueTo="100" />
+            </LinearLayout>
+
+            <LinearLayout
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:gravity="center_vertical"
+                android:orientation="horizontal">
+
+                <TextView
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content"
+                    android:text="高度范围：" />
+
+                <com.google.android.material.slider.RangeSlider
+                    android:id="@+id/height_range"
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_weight="1"
+                    android:valueFrom="0"
+                    android:valueTo="100" />
+            </LinearLayout>
+
+            <Switch
+                android:id="@+id/switch_grid"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:switchPadding="16dp"
+                android:text="栅格网" />
+
+            <Switch
+                android:id="@+id/switch_triangle"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:switchPadding="16dp"
+                android:text="三角网" />
+
+            <LinearLayout
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content">
+
+                <TextView
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content"
+                    android:text="坐标数量：" />
+
+                <TextView
+                    android:id="@+id/point_count"
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content" />
+            </LinearLayout>
+
+            <Button
+                android:id="@+id/update"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:text="刷新界面" />
+
+            <Button
+                android:id="@+id/clear_points"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:text="清除所有点" />
+
+            <LinearLayout
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:gravity="center_vertical"
+                android:orientation="horizontal">
+
+                <TextView
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content"
+                    android:text="坡向(角度)：" />
+
+                <com.google.android.material.slider.Slider
+                    android:id="@+id/slope_direction"
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_weight="1"
+                    android:valueFrom="0"
+                    android:valueTo="360" />
+            </LinearLayout>
+
+            <LinearLayout
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:gravity="center_vertical"
+                android:orientation="horizontal">
+
+                <TextView
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content"
+                    android:text="坡度(%)：" />
+
+                <com.google.android.material.slider.Slider
+                    android:id="@+id/slope_percentage"
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_weight="1"
+                    android:valueFrom="0"
+                    android:valueTo="100" />
+            </LinearLayout>
+
+            <LinearLayout
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:gravity="center_vertical">
+
+                <TextView
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content"
+                    android:text="设计面高度(m)：" />
+
+                <com.google.android.material.slider.Slider
+                    android:id="@+id/design_height"
+                    android:layout_width="match_parent"
+                    android:layout_height="wrap_content"
+                    android:value="0"
+                    android:valueFrom="-100"
+                    android:valueTo="100" />
+            </LinearLayout>
+
+            <Switch
+                android:id="@+id/switch_design_surface"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:switchPadding="16dp"
+                android:text="显示设计面" />
+
+            <Switch
+                android:id="@+id/switch_slope_result"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:switchPadding="16dp"
+                android:text="显示计算的坡面" />
+        </LinearLayout>
+    </ScrollView>
+</LinearLayout>

android/src/main/res/layout/activity_main.xml

@@ -0,0 +1,186 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:id="@+id/main"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="horizontal"
+    tools:context=".MainActivity">
+
+    <LinearLayout
+        android:layout_width="0dp"
+        android:layout_height="match_parent"
+        android:layout_weight="1"
+        android:orientation="vertical"
+        android:paddingTop="32dp">
+
+        <com.google.android.material.slider.Slider
+            android:id="@+id/slider_target_height"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:value="0"
+            android:valueFrom="0"
+            android:valueTo="100" />
+
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:gravity="center_vertical"
+            android:orientation="horizontal">
+
+            <TextView
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:text="栅格大小：" />
+
+            <com.google.android.material.slider.Slider
+                android:id="@+id/cell_size"
+                android:layout_width="0dp"
+                android:layout_height="wrap_content"
+                android:layout_weight="1"
+                android:value="1"
+                android:valueFrom="1"
+                android:valueTo="100" />
+        </LinearLayout>
+
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:gravity="center_vertical"
+            android:orientation="horizontal">
+
+            <TextView
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:text="高度范围：" />
+
+            <com.google.android.material.slider.RangeSlider
+                android:id="@+id/height_range"
+                android:layout_width="0dp"
+                android:layout_height="wrap_content"
+                android:layout_weight="1"
+                android:valueFrom="0"
+                android:valueTo="100" />
+        </LinearLayout>
+
+        <Switch
+            android:id="@+id/switch_grid"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:switchPadding="16dp"
+            android:text="栅格网" />
+
+        <Switch
+            android:id="@+id/switch_triangle"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:switchPadding="16dp"
+            android:text="三角网" />
+
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content">
+
+            <TextView
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:text="坐标数量：" />
+
+            <TextView
+                android:id="@+id/point_count"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content" />
+        </LinearLayout>
+
+        <Button
+            android:id="@+id/update"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:text="刷新界面" />
+
+        <Button
+            android:id="@+id/clear_points"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:text="清除所有点" />
+
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:gravity="center_vertical"
+            android:orientation="horizontal">
+
+            <TextView
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:text="坡向(角度)：" />
+
+            <com.google.android.material.slider.Slider
+                android:id="@+id/slope_direction"
+                android:layout_width="0dp"
+                android:layout_height="wrap_content"
+                android:layout_weight="1"
+                android:valueFrom="0"
+                android:valueTo="360" />
+        </LinearLayout>
+
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:gravity="center_vertical"
+            android:orientation="horizontal">
+
+            <TextView
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:text="坡度(%)：" />
+
+            <com.google.android.material.slider.Slider
+                android:id="@+id/slope_percentage"
+                android:layout_width="0dp"
+                android:layout_height="wrap_content"
+                android:layout_weight="1"
+                android:valueFrom="0"
+                android:valueTo="100" />
+        </LinearLayout>
+
+        <LinearLayout
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:gravity="center_vertical">
+
+            <TextView
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:text="设计面高度(m)：" />
+
+            <com.google.android.material.slider.Slider
+                android:id="@+id/design_height"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:value="0"
+                android:valueFrom="-100"
+                android:valueTo="100" />
+        </LinearLayout>
+
+        <Switch
+            android:id="@+id/switch_design_surface"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:switchPadding="16dp"
+            android:text="显示设计面" />
+
+        <Switch
+            android:id="@+id/switch_slope_result"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:switchPadding="16dp"
+            android:text="显示计算的坡面" />
+    </LinearLayout>
+
+    <com.mapbox.maps.MapView
+        android:id="@+id/map_view"
+        android:layout_width="0dp"
+        android:layout_height="match_parent"
+        android:layout_weight="3" />
+</LinearLayout>

android/src/main/res/mipmap-anydpi/ic_launcher.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@drawable/ic_launcher_background" />
+    <foreground android:drawable="@drawable/ic_launcher_foreground" />
+    <monochrome android:drawable="@drawable/ic_launcher_foreground" />
+</adaptive-icon>

android/src/main/res/mipmap-anydpi/ic_launcher_round.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@drawable/ic_launcher_background" />
+    <foreground android:drawable="@drawable/ic_launcher_foreground" />
+    <monochrome android:drawable="@drawable/ic_launcher_foreground" />
+</adaptive-icon>

android/src/main/res/values-night/themes.xml

@@ -0,0 +1,7 @@
+<resources xmlns:tools="http://schemas.android.com/tools">
+    <!-- Base application theme. -->
+    <style name="Base.Theme.Orx" parent="Theme.Material3.DayNight.NoActionBar">
+        <!-- Customize your dark theme here. -->
+        <!-- <item name="colorPrimary">@color/my_dark_primary</item> -->
+    </style>
+</resources>

android/src/main/res/values/colors.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <color name="black">#FF000000</color>
+    <color name="white">#FFFFFFFF</color>
+</resources>

android/src/main/res/values/mapbox_access_token.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources xmlns:tools="http://schemas.android.com/tools">
+    <string name="mapbox_access_token" translatable="false" tools:ignore="UnusedResources">pk.eyJ1IjoienpxMSIsImEiOiJjbWYzbzV1MzQwMHJvMmpvbG1wbjJwdjUyIn0.LvKjIrCv9dAFcGxOM52f2Q</string>
+</resources>

android/src/main/res/values/strings.xml

@@ -0,0 +1,3 @@
+<resources>
+    <string name="app_name">icegps-orx</string>
+</resources>

android/src/main/res/values/themes.xml

@@ -0,0 +1,9 @@
+<resources xmlns:tools="http://schemas.android.com/tools">
+    <!-- Base application theme. -->
+    <style name="Base.Theme.Orx" parent="Theme.Material3.DayNight.NoActionBar">
+        <!-- Customize your light theme here. -->
+        <!-- <item name="colorPrimary">@color/my_light_primary</item> -->
+    </style>
+
+    <style name="Theme.Orx" parent="Base.Theme.Orx" />
+</resources>

android/src/test/java/com/icegps/geotools/ExampleUnitTest.kt

@@ -0,0 +1,17 @@
+package com.icegps.geotools
+
+import org.junit.Test
+
+import org.junit.Assert.*
+
+/**
+ * Example local unit test, which will execute on the development machine (host).
+ *
+ * See [testing documentation](http://d.android.com/tools/testing).
+ */
+class ExampleUnitTest {
+    @Test
+    fun addition_isCorrect() {
+        assertEquals(4, 2 + 2)
+    }
+}

android/src/test/java/com/icegps/geotools/TriangulationToGridTest.kt

@@ -0,0 +1,71 @@
+package com.icegps.geotools
+
+import com.icegps.geotools.ktx.area
+import com.icegps.geotools.ktx.niceStr
+import com.icegps.math.geometry.Vector3D
+import com.icegps.triangulation.delaunayTriangulation
+import org.junit.Test
+import kotlin.math.max
+
+/**
+ * @author tabidachinokaze
+ * @date 2025/11/26
+ */
+class TriangulationToGridTest {
+    @Test
+    fun testTriangulationToGrid() {
+        val points = listOf(
+            Vector3D(-10.0, 10.0, 0.0),
+            Vector3D(10.0, 10.0, 10.0),
+            Vector3D(-10.0, -10.0, 20.0),
+            Vector3D(10.0, -10.0, 30.0),
+        )
+        points.map {
+            it / 8
+        }.niceStr().let(::println)
+        val area = points.area
+        val cellSize = max(area.x + area.width, area.y + area.height) / 10
+        val triangulation = points.delaunayTriangulation()
+        val triangles = triangulation.triangles()
+        val grid = triangulationToGrid(
+            delaunator = triangulation,
+            cellSize = cellSize,
+        )
+        grid.string().let(::println)
+        val slopeResult = SlopeCalculator.calculateSlope(
+            grid = grid,
+            slopeDirection = 0.0,
+            slopePercentage = 100.0,
+            baseHeightOffset = 0.0
+        )
+        slopeResult.designSurface.string().let(::println)
+        println("原来的 Volume: ${grid.volumeSum()}")
+        println("做坡的 Volume: ${slopeResult.designSurface.volumeSum()}")
+        println(slopeResult.earthworkResult)
+    }
+}
+
+fun GridModel.string() = buildString {
+    for (r in 0 until rows) {
+        for (c in 0 until cols) {
+            val originalElev = getValue(r, c) ?: continue
+            append("${originalElev.format()}, ")
+        }
+        appendLine()
+    }
+}
+
+fun GridModel.volumeSum(): Double {
+    var volume = 0.0
+    for (r in 0 until rows) {
+        for (c in 0 until cols) {
+            val height = getValue(r, c) ?: continue
+            volume += height
+        }
+    }
+    return volume
+}
+
+fun Double.format(): String {
+    return "%.1f".format(this)
+}

build.gradle

@@ -0,0 +1,6 @@
+plugins {
+    alias(libs.plugins.android.application) apply false
+    alias(libs.plugins.kotlin.android) apply false
+    alias(libs.plugins.kotlin.jvm) apply false
+    alias(libs.plugins.android.library) apply false
+}

gradle.properties

@@ -0,0 +1,23 @@
+# Project-wide Gradle settings.
+# IDE (e.g. Android Studio) users:
+# Gradle settings configured through the IDE *will override*
+# any settings specified in this file.
+# For more details on how to configure your build environment visit
+# http://www.gradle.org/docs/current/userguide/build_environment.html
+# Specifies the JVM arguments used for the daemon process.
+# The setting is particularly useful for tweaking memory settings.
+org.gradle.jvmargs=-Xmx2048m -Dfile.encoding=UTF-8
+# When configured, Gradle will run in incubating parallel mode.
+# This option should only be used with decoupled projects. For more details, visit
+# https://developer.android.com/r/tools/gradle-multi-project-decoupled-projects
+# org.gradle.parallel=true
+# AndroidX package structure to make it clearer which packages are bundled with the
+# Android operating system, and which are packaged with your app's APK
+# https://developer.android.com/topic/libraries/support-library/androidx-rn
+android.useAndroidX=true
+# Kotlin code style for this project: "official" or "obsolete":
+kotlin.code.style=official
+# Enables namespacing of each library's R class so that its R class includes only the
+# resources declared in the library itself and none from the library's dependencies,
+# thereby reducing the size of the R class for that library
+android.nonTransitiveRClass=true

gradle/libs.versions.toml

@@ -0,0 +1,42 @@
+[versions]
+kotlin = "2.2.21"
+ktor = "3.3.2"
+agp = "8.13.1"
+junit = "4.13.2"
+coreKtx = "1.17.0"
+junitVersion = "1.3.0"
+espressoCoreVersion = "3.7.0"
+appcompat = "1.7.1"
+material = "1.13.0"
+activity = "1.12.0"
+constraintlayout = "2.2.1"
+lifecycleRuntimeKtx = "2.10.0"
+kotlinx-serialization = "1.9.0"
+mapbox = "11.16.6"
+
+[libraries]
+junit = { group = "junit", name = "junit", version.ref = "junit" }
+core-ktx = { group = "androidx.core", name = "core-ktx", version.ref = "coreKtx" }
+ext-junit = { group = "androidx.test.ext", name = "junit", version.ref = "junitVersion" }
+androidx-espresso-core = { group = "androidx.test.espresso", name = "espresso-core", version.ref = "espressoCoreVersion" }
+androidx-appcompat = { group = "androidx.appcompat", name = "appcompat", version.ref = "appcompat" }
+material = { group = "com.google.android.material", name = "material", version.ref = "material" }
+androidx-activity = { group = "androidx.activity", name = "activity", version.ref = "activity" }
+androidx-constraintlayout = { group = "androidx.constraintlayout", name = "constraintlayout", version.ref = "constraintlayout" }
+androidx-lifecycle-runtime-ktx = { group = "androidx.lifecycle", name = "lifecycle-runtime-ktx", version.ref = "lifecycleRuntimeKtx" }
+#ktor
+ktor-client-core = { group = "io.ktor", name = "ktor-client-core", version.ref = "ktor" }
+ktor-client-cio = { group = "io.ktor", name = "ktor-client-cio", version.ref = "ktor" }
+ktor-client-logging = { group = "io.ktor", name = "ktor-client-logging", version.ref = "ktor" }
+ktor-client-content-negotiation = { group = "io.ktor", name = "ktor-client-content-negotiation", version.ref = "ktor" }
+ktor-serialization-kotlinx-json = { group = "io.ktor", name = "ktor-serialization-kotlinx-json", version.ref = "ktor" }
+
+kotlinx-serialization-json = { group = "org.jetbrains.kotlinx", name = "kotlinx-serialization-json", version.ref = "kotlinx-serialization" }
+mapbox-maps = { module = "com.mapbox.maps:android-ndk27", version.ref = "mapbox" }
+
+[plugins]
+kotlin-serialization = { id = "org.jetbrains.kotlin.plugin.serialization", version.ref = "kotlin" }
+android-application = { id = "com.android.application", version.ref = "agp" }
+kotlin-android = { id = "org.jetbrains.kotlin.android", version.ref = "kotlin" }
+kotlin-jvm = { id = "org.jetbrains.kotlin.jvm", version.ref = "kotlin" }
+android-library = { id = "com.android.library", version.ref = "agp" }

gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,7 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.2.0-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

gradlew

@@ -0,0 +1,248 @@
+#!/bin/sh
+
+#
+# Copyright © 2015 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+##############################################################################
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/HEAD/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+# This is normally unused
+# shellcheck disable=SC2034
+APP_BASE_NAME=${0##*/}
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd -P "${APP_HOME:-./}" > /dev/null && printf '%s\n' "$PWD" ) || exit
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD=$JAVA_HOME/jre/sh/java
+    else
+        JAVACMD=$JAVA_HOME/bin/java
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -jar "$APP_HOME/gradle/wrapper/gradle-wrapper.jar" \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"

gradlew.bat

@@ -0,0 +1,93 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+@rem SPDX-License-Identifier: Apache-2.0
+@rem
+
+@if "%DEBUG%"=="" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if %ERRORLEVEL% equ 0 goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -jar "%APP_HOME%\gradle\wrapper\gradle-wrapper.jar" %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if %ERRORLEVEL% equ 0 goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

icegps-common/.gitignore

@@ -0,0 +1 @@
+/build

icegps-common/build.gradle.kts

@@ -0,0 +1,44 @@
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+
+plugins {
+    alias(libs.plugins.android.library)
+    alias(libs.plugins.kotlin.android)
+}
+
+android {
+    namespace = "com.icegps.common"
+    compileSdk {
+        version = release(36)
+    }
+
+    defaultConfig {
+        minSdk = 28
+
+        testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
+        consumerProguardFiles("consumer-rules.pro")
+    }
+
+    buildTypes {
+        release {
+            isMinifyEnabled = false
+            proguardFiles(
+                getDefaultProguardFile("proguard-android-optimize.txt"),
+                "proguard-rules.pro"
+            )
+        }
+    }
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_17
+        targetCompatibility = JavaVersion.VERSION_17
+    }
+}
+
+kotlin {
+    compilerOptions.jvmTarget = JvmTarget.JVM_17
+}
+
+dependencies {
+    testImplementation(libs.junit)
+    androidTestImplementation(libs.ext.junit)
+    androidTestImplementation(libs.androidx.espresso.core)
+}

icegps-common/proguard-rules.pro

@@ -0,0 +1,21 @@
+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile

icegps-common/src/androidTest/java/com/icegps/common/ExampleInstrumentedTest.kt

@@ -0,0 +1,24 @@
+package com.icegps.common
+
+import androidx.test.platform.app.InstrumentationRegistry
+import androidx.test.ext.junit.runners.AndroidJUnit4
+
+import org.junit.Test
+import org.junit.runner.RunWith
+
+import org.junit.Assert.*
+
+/**
+ * Instrumented test, which will execute on an Android device.
+ *
+ * See [testing documentation](http://d.android.com/tools/testing).
+ */
+@RunWith(AndroidJUnit4::class)
+class ExampleInstrumentedTest {
+    @Test
+    fun useAppContext() {
+        // Context of the app under test.
+        val appContext = InstrumentationRegistry.getInstrumentation().targetContext
+        assertEquals("com.icegps.common.test", appContext.packageName)
+    }
+}

icegps-common/src/main/AndroidManifest.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+
+</manifest>

icegps-common/src/main/java/com/icegps/common/helper/BlhToEnu.kt

@@ -0,0 +1,274 @@
+package com.icegps.common.helper
+
+import kotlin.math.atan2
+import kotlin.math.cos
+import kotlin.math.pow
+import kotlin.math.sin
+import kotlin.math.sqrt
+
+/**
+ * BLH -> ENU
+ *
+ * @author lm
+ * @date 2025/3/12
+ * @link https://gist.github.com/komasaru/6ce0634475923ddac597f868288c54e9
+ */
+class BlhToEnu {
+
+    companion object {
+        private const val PI_180 = Math.PI / 180.0
+
+        // WGS84 坐标参数
+        private const val A = 6378137.0 // a（地球椭球体长半径（赤道面平均半径））
+        private const val ONE_F = 298.257223563 // 1 / f（地球椭球体扁平率 = (a - b) / a）
+        private val B = A * (1.0 - 1.0 / ONE_F) // b（地球椭球体短半径）
+        private val E2 = (1.0 / ONE_F) * (2 - (1.0 / ONE_F))
+
+        // e^2 = 2 * f - f * f = (a^2 - b^2) / a^2
+        private val ED2 = E2 * A * A / (B * B) // e'^2 = (a^2 - b^2) / b^2
+    }
+
+    private var originLat: Double = 0.0
+    private var originLon: Double = 0.0
+    private var originHeight: Double = 0.0
+    private var isOriginSet: Boolean = false
+
+    fun getOriginLat(): Double = originLat
+
+    fun getOriginLon(): Double = originLon
+
+    fun getOriginHeight(): Double = originHeight
+
+    fun resetEnuBenchmarkPoint() {
+        isOriginSet = false
+    }
+
+    fun wgs84ToEnu(lat: Double, lon: Double, height: Double = 0.0): DoubleArray {
+        if (!isOriginSet) {
+            originLat = lat
+            originLon = lon
+            originHeight = height
+            isOriginSet = true
+            return doubleArrayOf(0.0, 0.0, 0.0)
+        }
+
+        val enu = blh2enu(originLat, originLon, originHeight, lat, lon, height)
+//        var az = atan2(enu[0], enu[1]) * 180.0 / Math.PI
+//        if (az < 0.0) {
+//            az += 360.0
+//        }
+//        val el = atan2(
+//            enu[2],
+//            sqrt(enu[0] * enu[0] + enu[1] * enu[1])
+//        ) * 180.0 / Math.PI
+//        val dst = sqrt(enu.sumOf { it * it })
+
+//        println("--->")
+//        println(
+//            """
+//            ENU: E = ${enu[0].format(3)}m
+//                 N = ${enu[1].format(3)}m
+//                 U = ${enu[2].format(3)}m
+//            方位角 = ${az.format(3)}°
+//              仰角 = ${el.format(3)}°
+//              距离 = ${dst.format(3)}m
+//        """.trimIndent()
+//        )
+
+        return enu
+    }
+
+    fun enuToWgs84(e: Double, n: Double, u: Double): DoubleArray {
+        if (!isOriginSet) {
+            return doubleArrayOf(0.0, 0.0, 0.0)
+        }
+
+        val blh = enu2blh(originLat, originLon, originHeight, e, n, u)
+
+//        println("--->")
+//        println(
+//            """
+//            BLH: Beta = ${blh[0].format(8)}°
+//                 Lambda = ${blh[1].format(8)}°
+//                 Height = ${blh[2].format(3)}m
+//        """.trimIndent()
+//        )
+
+        return blh
+    }
+
+    private fun Double.format(digits: Int) = "%.${digits}f".format(this)
+
+    /**
+     * BLH -> ENU 转换(East, North, Up)
+     *
+     * @param bO 原点 Beta(纬度)
+     * @param lO 原点 Lambda(经度)
+     * @param hO 原点 Height(高度)
+     * @param b 目标点 Beta(纬度)
+     * @param l 目标点 Lambda(经度)
+     * @param h 目标点 Height(高度)
+     * @return ENU 坐标 [e, n, u]
+     */
+    private fun blh2enu(bO: Double, lO: Double, hO: Double, b: Double, l: Double, h: Double): DoubleArray {
+        val (xO, yO, zO) = blh2ecef(bO, lO, hO)
+        val (x, y, z) = blh2ecef(b, l, h)
+        val mat0 = matZ(90.0)
+        val mat1 = matY(90.0 - bO)
+        val mat2 = matZ(lO)
+        val mat = mulMat(mulMat(mat0, mat1), mat2)
+        return rotate(mat, doubleArrayOf(x - xO, y - yO, z - zO))
+    }
+
+    /**
+     * BLH -> ECEF 转换
+     *
+     * @param lat 纬度
+     * @param lon 经度
+     * @param height 高度
+     * @return ECEF 坐标 [x, y, z]
+     */
+    private fun blh2ecef(lat: Double, lon: Double, height: Double): DoubleArray {
+        val n = { x: Double -> A / sqrt(1.0 - E2 * sin(x * PI_180).pow(2)) }
+        val x = (n(lat) + height) * cos(lat * PI_180) * cos(lon * PI_180)
+        val y = (n(lat) + height) * cos(lat * PI_180) * sin(lon * PI_180)
+        val z = (n(lat) * (1.0 - E2) + height) * sin(lat * PI_180)
+        return doubleArrayOf(x, y, z)
+    }
+
+    /**
+     * ENU -> BLH 转换
+     *
+     * @param e East 坐标
+     * @param n North 坐标
+     * @param u Up 坐标
+     * @return WGS84 坐标 [纬度, 经度, 高度]
+     */
+    private fun enu2blh(bO: Double, lO: Double, hO: Double, e: Double, n: Double, u: Double): DoubleArray {
+        val mat0 = matZ(-lO)
+        val mat1 = matY(-(90.0 - bO))
+        val mat2 = matZ(-90.0)
+        val mat = mulMat(mulMat(mat0, mat1), mat2)
+
+        val enu = doubleArrayOf(e, n, u)
+        val xyz = rotate(mat, enu)
+
+        val (xO, yO, zO) = blh2ecef(bO, lO, hO)
+        val x = xyz[0] + xO
+        val y = xyz[1] + yO
+        val z = xyz[2] + zO
+
+        return ecef2blh(x, y, z)
+    }
+
+    /**
+     * ECEF -> BLH 转换
+     *
+     * @param x ECEF X 坐标
+     * @param y ECEF Y 坐标
+     * @param z ECEF Z 坐标
+     * @return WGS84 坐标 [纬度, 经度, 高度]
+     */
+    private fun ecef2blh(x: Double, y: Double, z: Double): DoubleArray {
+        val p = sqrt(x * x + y * y)
+        val theta = atan2(z * A, p * B)
+        val sinTheta = sin(theta)
+        val cosTheta = cos(theta)
+
+        val lat = atan2(
+            z + ED2 * B * sinTheta.pow(3),
+            p - E2 * A * cosTheta.pow(3)
+        )
+        val lon = atan2(y, x)
+
+        val sinLat = sin(lat)
+        val n = A / sqrt(1.0 - E2 * sinLat * sinLat)
+        val h = p / cos(lat) - n
+
+        return doubleArrayOf(
+            lat * 180.0 / Math.PI,
+            lon * 180.0 / Math.PI,
+            h
+        )
+    }
+
+    /**
+     * 以 x 轴为轴的旋转矩阵
+     *
+     * @param ang 旋转角度（°）
+     * @return 旋转矩阵（3x3）
+     */
+    private fun matX(ang: Double): Array<DoubleArray> {
+        val a = ang * PI_180
+        val c = cos(a)
+        val s = sin(a)
+        return arrayOf(
+            doubleArrayOf(1.0, 0.0, 0.0),
+            doubleArrayOf(0.0, c, s),
+            doubleArrayOf(0.0, -s, c)
+        )
+    }
+
+    /**
+     * 以 y 轴为轴的旋转矩阵
+     *
+     * @param ang 旋转角度（°）
+     * @return 旋转矩阵（3x3）
+     */
+    private fun matY(ang: Double): Array<DoubleArray> {
+        val a = ang * PI_180
+        val c = cos(a)
+        val s = sin(a)
+        return arrayOf(
+            doubleArrayOf(c, 0.0, -s),
+            doubleArrayOf(0.0, 1.0, 0.0),
+            doubleArrayOf(s, 0.0, c)
+        )
+    }
+
+    /**
+     * 以 z 轴为轴的旋转矩阵
+     *
+     * @param ang 旋转角度（°）
+     * @return 旋转矩阵（3x3）
+     */
+    private fun matZ(ang: Double): Array<DoubleArray> {
+        val a = ang * PI_180
+        val c = cos(a)
+        val s = sin(a)
+        return arrayOf(
+            doubleArrayOf(c, s, 0.0),
+            doubleArrayOf(-s, c, 0.0),
+            doubleArrayOf(0.0, 0.0, 1.0)
+        )
+    }
+
+    /**
+     * 两个矩阵(3x3)的乘积
+     *
+     * @param matA 3x3 矩阵
+     * @param matB 3x3 矩阵
+     * @return 3x3 矩阵
+     */
+    private fun mulMat(matA: Array<DoubleArray>, matB: Array<DoubleArray>): Array<DoubleArray> {
+        return Array(3) { k ->
+            DoubleArray(3) { j ->
+                (0..2).sumOf { i -> matA[k][i] * matB[i][j] }
+            }
+        }
+    }
+
+    /**
+     * 点的旋转
+     *
+     * @param mat 3x3 旋转矩阵
+     * @param pt 旋转前坐标 [x, y, z]
+     * @return 旋转后坐标 [x, y, z]
+     */
+    private fun rotate(mat: Array<DoubleArray>, pt: DoubleArray): DoubleArray {
+        return DoubleArray(3) { j ->
+            (0..2).sumOf { i -> mat[j][i] * pt[i] }
+        }
+    }
+
+}

icegps-common/src/main/java/com/icegps/common/helper/GeoHelper.kt

@@ -0,0 +1,419 @@
+package com.icegps.common.helper
+
+import android.os.Parcel
+import android.os.Parcelable
+import kotlin.math.atan
+import kotlin.math.atan2
+import kotlin.math.cbrt
+import kotlin.math.cos
+import kotlin.math.exp
+import kotlin.math.ln
+import kotlin.math.sin
+import kotlin.math.sqrt
+import kotlin.math.tan
+
+/**
+ * WGS84、EPSG3857、ENU 的坐标转换工具类
+ *
+ * @author lm
+ * @date 2024/8/2
+ */
+class GeoHelper private constructor() {
+
+    companion object {
+        private var sharedInstance: GeoHelper? = null
+        fun getSharedInstance(): GeoHelper = sharedInstance ?: GeoHelper().also { sharedInstance = it }
+        fun createInstance(): GeoHelper = GeoHelper()
+    }
+
+    // WGS-84 ellipsoid parameters
+    private val RADIUS = 6378137.0 // Major radius
+    private val RADIUS_B = 6356752.314245 // Minor radius
+    private val E = (RADIUS * RADIUS - RADIUS_B * RADIUS_B) / (RADIUS * RADIUS) // Eccentricity
+    private val HALF_SIZE = Math.PI * RADIUS // Half circumference of Earth
+    private val DEG2RAD = Math.PI / 180 // Degrees to radians conversion factor
+    private val RAD2DEG = 180 / Math.PI // Radians to degrees conversion factor
+    private val RE_WGS84 = 6378137.0 // Earth's equatorial radius in WGS84
+    private val FE_WGS84 = 1.0 / 298.257223563 // Flattening of the WGS84 ellipsoid
+
+    private var isFirstPoint = true
+    private var firstPoint = DoubleArray(3)
+    private val bPos = DoubleArray(3)
+    private var bECEF = DoubleArray(3)
+    private val rPos = DoubleArray(3)
+    private var rECEF = DoubleArray(3)
+    private val vECEF = DoubleArray(3)
+
+    private var useBlhToEnu = true
+    private var blhToEnu = BlhToEnu()
+
+    /**
+     * 将 WGS84 坐标转换为 ENU (East-North-Up) 坐标
+     * 如果是第一个点，它将被设置为 ENU 坐标系的基准点
+     *
+     * @param lon 经度（度）
+     * @param lat 纬度（度）
+     * @param hgt 高度（米）
+     * @return 包含 ENU 坐标的 Enu 对象
+     */
+    fun wgs84ToENU(lon: Double, lat: Double, hgt: Double): ENU {
+        if (useBlhToEnu) {
+            val enu = blhToEnu.wgs84ToEnu(lon = lon, lat = lat, height = hgt)
+            return ENU(enu[0], enu[1], enu[2])
+        }
+
+        if (isFirstPoint) setEnuBenchmark(lon, lat, hgt)
+        rPos[0] = lat * DEG2RAD
+        rPos[1] = lon * DEG2RAD
+        rPos[2] = hgt
+
+        rECEF = pos2ecef(rPos)
+        vECEF[0] = rECEF[0] - bECEF[0]
+        vECEF[1] = rECEF[1] - bECEF[1]
+        vECEF[2] = rECEF[2] - bECEF[2]
+        val enuDoubleArray = ecef2enu(bPos, vECEF)
+        return ENU(enuDoubleArray[0], enuDoubleArray[1], enuDoubleArray[2])
+    }
+
+    /**
+     * 将 WGS84 坐标转换为 ENU (East-North-Up) 坐标
+     * 如果是第一个点，它将被设置为 ENU 坐标系的基准点
+     *
+     * @param wgs84 WGS84 坐标对象
+     * @return 包含 ENU 坐标的 Enu 对象
+     */
+    fun wgs84ObjectToENU(wgs84: WGS84): ENU = wgs84ToENU(wgs84.lon, wgs84.lat, wgs84.hgt)
+
+    /**
+     * 是否已设置 ENU 坐标系的基准点
+     */
+    fun isEnuBenchmarkSet(): Boolean = !isFirstPoint
+
+    /**
+     * 设置 ENU 坐标系的基准点
+     *
+     * @param lon 基准点经度（度）
+     * @param lat 基准点纬度（度）
+     * @param hgt 基准点高度（米）
+     */
+    private fun setEnuBenchmark(lon: Double, lat: Double, hgt: Double) {
+        firstPoint = doubleArrayOf(lon, lat, hgt)
+        bPos[0] = lat * DEG2RAD
+        bPos[1] = lon * DEG2RAD
+        bPos[2] = hgt
+        bECEF = pos2ecef(bPos)
+        isFirstPoint = false
+    }
+
+    /**
+     * 获取 ENU 坐标系的基准点
+     *
+     * @return 包含 WGS84 坐标 {经度, 纬度, 高度} 的 DoubleArray
+     */
+    fun getEnuBenchmarkPoint(): DoubleArray {
+        if (useBlhToEnu) {
+            return doubleArrayOf(blhToEnu.getOriginLon(), blhToEnu.getOriginLat(), blhToEnu.getOriginHeight())
+        }
+        return firstPoint
+    }
+
+    /**
+     * 获取 ENU 坐标系的基准点
+     *
+     * @return 包含 WGS84 坐标的 WGS84 对象
+     */
+    fun getEnuBenchmarkPointAsWGS84(): WGS84 {
+        if (useBlhToEnu) {
+            return WGS84(blhToEnu.getOriginLon(), blhToEnu.getOriginLat(), blhToEnu.getOriginHeight())
+        }
+        return WGS84(firstPoint[0], firstPoint[1], firstPoint[2])
+    }
+
+    /**
+     * 重置 ENU 基准点
+     * 调用此方法后，下一次 wgs84ToENU 调用将设置新的基准点
+     */
+    fun resetEnuBenchmarkPoint() {
+        if (useBlhToEnu) {
+            blhToEnu.resetEnuBenchmarkPoint()
+            return
+        }
+        isFirstPoint = true
+    }
+
+    /**
+     * 将 ENU (East-North-Up) 坐标转换为 WGS84 坐标
+     *
+     * @param enu 包含 ENU 坐标的 Enu 对象
+     * @return 包含 WGS84 坐标 {经度, 纬度, 高度} 的 DoubleArray
+     */
+    fun enuToWGS84(enu: ENU): DoubleArray {
+        if (useBlhToEnu) {
+            val wgs84 = blhToEnu.enuToWgs84(e = enu.x, n = enu.y, u = enu.z)
+            return doubleArrayOf(wgs84[1], wgs84[0], wgs84[2])
+        }
+
+        val enuArray = doubleArrayOf(enu.x, enu.y, enu.z)
+        val enuToEcefMatrix = xyz2enu(bPos)
+        val ecefArray = matmul(charArrayOf('T', 'N'), 3, 1, 3, 1.0, enuToEcefMatrix, enuArray, 0.0)
+        vECEF[0] = bECEF[0] + ecefArray[0]
+        vECEF[1] = bECEF[1] + ecefArray[1]
+        vECEF[2] = bECEF[2] + ecefArray[2]
+        return ecef2pos(vECEF)
+    }
+
+    /**
+     * 将 ENU (East-North-Up) 坐标转换为 WGS84 坐标
+     *
+     * @param enu 包含 ENU 坐标的 Enu 对象
+     * @return 包含 WGS84 坐标的 WGS84 对象
+     */
+    fun enuToWGS84Object(enu: ENU): WGS84 {
+        val wgs84Array = enuToWGS84(enu)
+        return WGS84(wgs84Array[0], wgs84Array[1], wgs84Array[2])
+    }
+
+    /**
+     * 将 WGS84 坐标转换为 EPSG3857 坐标
+     *
+     * @param lon 经度（度）
+     * @param lat 纬度（度）
+     * @return 包含 EPSG3857 坐标的 EPSG3857 对象
+     */
+    fun wgs84ToEPSG3857(lon: Double, lat: Double): EPSG3857 {
+        val x = lon * HALF_SIZE / 180
+        var y = RADIUS * ln(tan(Math.PI * (lat + 90) / 360))
+        y = y.coerceIn(-HALF_SIZE, HALF_SIZE)
+        return EPSG3857(x, y)
+    }
+
+    /**
+     * 将 WGS84 坐标转换为 EPSG3857 坐标
+     *
+     * @param wgs84 WGS84 坐标对象
+     * @return 包含 EPSG3857 坐标的 EPSG3857 对象
+     */
+    fun wgs84ObjectToEPSG3857(wgs84: WGS84): EPSG3857 = wgs84ToEPSG3857(wgs84.lon, wgs84.lat)
+
+    /**
+     * 将 EPSG3857 坐标转换为 WGS84 坐标
+     *
+     * @param epsg3857 包含 EPSG3857 坐标的 EPSG3857 对象
+     * @return 包含 WGS84 坐标 {经度, 纬度} 的 DoubleArray
+     */
+    fun epsg3857ToWGS84(epsg3857: EPSG3857): DoubleArray {
+        val lon = (epsg3857.x / HALF_SIZE) * 180.0
+        val lat = (2 * atan(exp(epsg3857.y / RADIUS)) - Math.PI / 2) * RAD2DEG
+        return doubleArrayOf(lon, lat)
+    }
+
+    /**
+     * 将 EPSG3857 坐标转换为 WGS84 坐标
+     *
+     * @param epsg3857 包含 EPSG3857 坐标的 EPSG3857 对象
+     * @return 包含 WGS84 坐标的 WGS84 对象
+     */
+    fun epsg3857ToWGS84Object(epsg3857: EPSG3857): WGS84 {
+        val wgs84Array = epsg3857ToWGS84(epsg3857)
+        return WGS84(wgs84Array[0], wgs84Array[1], 0.0)
+    }
+
+    fun pos2ecef(pos: DoubleArray): DoubleArray {
+        val (lat, lon, hgt) = pos
+        val sinp = sin(lat)
+        val cosp = cos(lat)
+        val sin_l = sin(lon)
+        val cos_l = cos(lon)
+        val e2 = FE_WGS84 * (2.0 - FE_WGS84)
+        val v = RE_WGS84 / sqrt(1.0 - e2 * sinp * sinp)
+
+        return doubleArrayOf(
+            (v + hgt) * cosp * cos_l,
+            (v + hgt) * cosp * sin_l,
+            (v * (1.0 - e2) + hgt) * sinp
+        )
+    }
+
+    fun ecef2enu(pos: DoubleArray, r: DoubleArray): DoubleArray {
+        val E = xyz2enu(pos)
+        return matmul(charArrayOf('N', 'N'), 3, 1, 3, 1.0, E, r, 0.0)
+    }
+
+    fun matmul(
+        tr: CharArray,
+        n: Int,
+        k: Int,
+        m: Int,
+        alpha: Double,
+        A: DoubleArray,
+        B: DoubleArray,
+        beta: Double
+    ): DoubleArray {
+        val f = when {
+            tr[0] == 'N' && tr[1] == 'N' -> 1
+            tr[0] == 'N' && tr[1] == 'T' -> 2
+            tr[0] == 'T' && tr[1] == 'N' -> 3
+            else -> 4
+        }
+        val C = DoubleArray(n * k)
+        for (i in 0 until n) {
+            for (j in 0 until k) {
+                var d = 0.0
+                when (f) {
+                    1 -> for (x in 0 until m) d += A[i + x * n] * B[x + j * m]
+                    2 -> for (x in 0 until m) d += A[i + x * n] * B[j + x * k]
+                    3 -> for (x in 0 until m) d += A[x + i * m] * B[x + j * m]
+                    4 -> for (x in 0 until m) d += A[x + i * m] * B[j + x * k]
+                }
+                C[i + j * n] = alpha * d + beta * C[i + j * n]
+            }
+        }
+        return C
+    }
+
+    fun xyz2enu(pos: DoubleArray): DoubleArray {
+        val (lat, lon) = pos
+        val sinp = sin(lat)
+        val cosp = cos(lat)
+        val sin_l = sin(lon)
+        val cos_l = cos(lon)
+
+        return doubleArrayOf(
+            -sin_l, cos_l, 0.0,
+            -sinp * cos_l, -sinp * sin_l, cosp,
+            cosp * cos_l, cosp * sin_l, sinp
+        )
+    }
+
+    fun ecef2pos(ecef: DoubleArray): DoubleArray {
+        val (x, y, z) = ecef
+        val a = RE_WGS84
+        val b = a * (1 - FE_WGS84)
+        val e2 = (a * a - b * b) / (a * a)
+        val e2p = (a * a - b * b) / (b * b)
+        val r2 = x * x + y * y
+        val r = sqrt(r2)
+        val E2 = a * a - b * b
+        val F = 54 * b * b * z * z
+        val G = r2 + (1 - e2) * z * z - e2 * E2
+        val c = (e2 * e2 * F * r2) / (G * G * G)
+        val s = cbrt(1 + c + sqrt(c * c + 2 * c))
+        val P = F / (3 * (s + 1 / s + 1) * (s + 1 / s + 1) * G * G)
+        val Q = sqrt(1 + 2 * e2 * e2 * P)
+        val r0 = -(P * e2 * r) / (1 + Q) + sqrt(0.5 * a * a * (1 + 1.0 / Q) - P * (1 - e2) * z * z / (Q * (1 + Q)) - 0.5 * P * r2)
+        val U = sqrt((r - e2 * r0) * (r - e2 * r0) + z * z)
+        val V = sqrt((r - e2 * r0) * (r - e2 * r0) + (1 - e2) * z * z)
+        val Z0 = b * b * z / (a * V)
+
+        val lon = atan2(y, x) * RAD2DEG
+        val lat = atan((z + e2p * Z0) / r) * RAD2DEG
+        val hgt = U * (1 - b * b / (a * V))
+        return doubleArrayOf(lon, lat, hgt)
+    }
+
+    data class WGS84(var lon: Double = 0.0, var lat: Double = 0.0, var hgt: Double = 0.0) : Parcelable {
+        constructor(parcel: Parcel) : this(
+            parcel.readDouble(),
+            parcel.readDouble(),
+            parcel.readDouble()
+        )
+
+        constructor(wgs84: DoubleArray) : this(
+            lon = wgs84.getOrElse(0) { 0.0 },
+            lat = wgs84.getOrElse(1) { 0.0 },
+            hgt = wgs84.getOrElse(2) { 0.0 }
+        )
+
+        override fun writeToParcel(parcel: Parcel, flags: Int) {
+            parcel.writeDouble(lon)
+            parcel.writeDouble(lat)
+            parcel.writeDouble(hgt)
+        }
+
+        override fun describeContents(): Int = 0
+
+        companion object CREATOR : Parcelable.Creator<WGS84> {
+            override fun createFromParcel(parcel: Parcel): WGS84 {
+                return WGS84(parcel)
+            }
+
+            override fun newArray(size: Int): Array<WGS84?> {
+                return arrayOfNulls(size)
+            }
+        }
+
+        override fun toString(): String {
+            return "WGS84(lon=$lon, lat=$lat, hgt=$hgt)"
+        }
+    }
+
+    data class EPSG3857(var x: Double = 0.0, var y: Double = 0.0) : Parcelable {
+        constructor(parcel: Parcel) : this(
+            parcel.readDouble(),
+            parcel.readDouble()
+        )
+
+        constructor(epsG3857: DoubleArray) : this(
+            x = epsG3857.getOrElse(0) { 0.0 },
+            y = epsG3857.getOrElse(1) { 0.0 }
+        )
+
+        override fun writeToParcel(parcel: Parcel, flags: Int) {
+            parcel.writeDouble(x)
+            parcel.writeDouble(y)
+        }
+
+        override fun describeContents(): Int = 0
+
+        companion object CREATOR : Parcelable.Creator<EPSG3857> {
+            override fun createFromParcel(parcel: Parcel): EPSG3857 {
+                return EPSG3857(parcel)
+            }
+
+            override fun newArray(size: Int): Array<EPSG3857?> {
+                return arrayOfNulls(size)
+            }
+        }
+
+        override fun toString(): String {
+            return "EPSG3857(x=$x, y=$y)"
+        }
+    }
+
+    data class ENU(var x: Double = 0.0, var y: Double = 0.0, var z: Double = 0.0) : Parcelable {
+        constructor(parcel: Parcel) : this(
+            parcel.readDouble(),
+            parcel.readDouble(),
+            parcel.readDouble()
+        )
+
+        constructor(enu: DoubleArray) : this(
+            x = enu.getOrElse(0) { 0.0 },
+            y = enu.getOrElse(1) { 0.0 },
+            z = enu.getOrElse(2) { 0.0 }
+        )
+
+        override fun writeToParcel(parcel: Parcel, flags: Int) {
+            parcel.writeDouble(x)
+            parcel.writeDouble(y)
+            parcel.writeDouble(z)
+        }
+
+        override fun describeContents(): Int = 0
+
+        companion object CREATOR : Parcelable.Creator<ENU> {
+            override fun createFromParcel(parcel: Parcel): ENU {
+                return ENU(parcel)
+            }
+
+            override fun newArray(size: Int): Array<ENU?> {
+                return arrayOfNulls(size)
+            }
+        }
+
+        override fun toString(): String {
+            return "ENU(x=$x, y=$y, z=$z)"
+        }
+    }
+
+}

icegps-common/src/test/java/com/icegps/common/ExampleUnitTest.kt

@@ -0,0 +1,17 @@
+package com.icegps.common
+
+import org.junit.Test
+
+import org.junit.Assert.*
+
+/**
+ * Example local unit test, which will execute on the development machine (host).
+ *
+ * See [testing documentation](http://d.android.com/tools/testing).
+ */
+class ExampleUnitTest {
+    @Test
+    fun addition_isCorrect() {
+        assertEquals(4, 2 + 2)
+    }
+}

icegps-shared/.gitignore

@@ -0,0 +1 @@
+/build

icegps-shared/build.gradle.kts

@@ -0,0 +1,57 @@
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+
+plugins {
+    alias(libs.plugins.android.library)
+    alias(libs.plugins.kotlin.android)
+    alias(libs.plugins.kotlin.serialization)
+}
+
+android {
+    namespace = "com.icegps.shared"
+    compileSdk {
+        version = release(36)
+    }
+
+    defaultConfig {
+        minSdk = 28
+
+        testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
+        consumerProguardFiles("consumer-rules.pro")
+    }
+
+    buildTypes {
+        release {
+            isMinifyEnabled = false
+            proguardFiles(
+                getDefaultProguardFile("proguard-android-optimize.txt"),
+                "proguard-rules.pro"
+            )
+        }
+    }
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_17
+        targetCompatibility = JavaVersion.VERSION_17
+    }
+}
+
+kotlin {
+    compilerOptions.jvmTarget = JvmTarget.JVM_17
+}
+
+dependencies {
+    implementation(libs.core.ktx)
+    implementation(libs.androidx.appcompat)
+    implementation(libs.material)
+
+    api(libs.kotlinx.serialization.json)
+    api(libs.ktor.client.core)
+    api(libs.ktor.client.cio)
+    api(libs.ktor.serialization.kotlinx.json)
+    api(libs.ktor.client.content.negotiation)
+    api(libs.ktor.client.logging)
+    api(project(":math"))
+
+    testImplementation(libs.junit)
+    androidTestImplementation(libs.ext.junit)
+    androidTestImplementation(libs.androidx.espresso.core)
+}

icegps-shared/proguard-rules.pro

@@ -0,0 +1,21 @@
+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile

icegps-shared/src/androidTest/java/com/icegps/shared/ExampleInstrumentedTest.kt

@@ -0,0 +1,24 @@
+package com.icegps.shared
+
+import androidx.test.platform.app.InstrumentationRegistry
+import androidx.test.ext.junit.runners.AndroidJUnit4
+
+import org.junit.Test
+import org.junit.runner.RunWith
+
+import org.junit.Assert.*
+
+/**
+ * Instrumented test, which will execute on an Android device.
+ *
+ * See [testing documentation](http://d.android.com/tools/testing).
+ */
+@RunWith(AndroidJUnit4::class)
+class ExampleInstrumentedTest {
+    @Test
+    fun useAppContext() {
+        // Context of the app under test.
+        val appContext = InstrumentationRegistry.getInstrumentation().targetContext
+        assertEquals("com.icegps.shared.test", appContext.packageName)
+    }
+}

icegps-shared/src/main/AndroidManifest.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+
+</manifest>

icegps-shared/src/main/java/com/icegps/shared/SharedHttpClient.kt

@@ -0,0 +1,42 @@
+package com.icegps.shared
+
+import io.ktor.client.HttpClient
+import io.ktor.client.engine.cio.CIO
+import io.ktor.client.plugins.HttpTimeout
+import io.ktor.client.plugins.contentnegotiation.ContentNegotiation
+import io.ktor.client.plugins.logging.LogLevel
+import io.ktor.client.plugins.logging.Logger
+import io.ktor.client.plugins.logging.Logging
+import io.ktor.client.plugins.logging.SIMPLE
+import io.ktor.http.ContentType
+import io.ktor.serialization.kotlinx.json.json
+import kotlinx.serialization.json.Json
+
+/**
+ * @author tabidachinokaze
+ * @date 2025/11/20
+ */
+@Suppress("FunctionName")
+fun SharedHttpClient(json: Json): HttpClient {
+    return HttpClient(CIO) {
+        install(ContentNegotiation) {
+            json(
+                json = json,
+                contentType = ContentType.Text.Html
+            )
+            json(
+                json = json,
+                contentType = ContentType.Application.Json
+            )
+        }
+        install(Logging) {
+            this.level = LogLevel.ALL
+            this.logger = Logger.SIMPLE
+        }
+        install(HttpTimeout) {
+            requestTimeoutMillis = 1000 * 60 * 10
+            connectTimeoutMillis = 1000 * 60 * 5
+            socketTimeoutMillis = 1000 * 60 * 10
+        }
+    }
+}

icegps-shared/src/main/java/com/icegps/shared/SharedJson.kt

@@ -0,0 +1,17 @@
+package com.icegps.shared
+
+import kotlinx.serialization.json.Json
+import kotlinx.serialization.modules.SerializersModule
+
+/**
+ * @author tabidachinokaze
+ * @date 2025/11/20
+ */
+@Suppress("FunctionName")
+fun SharedJson(): Json {
+    return Json {
+        ignoreUnknownKeys = true
+        serializersModule = SerializersModule {
+        }
+    }
+}

icegps-shared/src/main/java/com/icegps/shared/api/LookupResponse.kt

@@ -0,0 +1,21 @@
+package com.icegps.shared.api
+
+import com.icegps.shared.model.IGeoPoint
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class LookupResponse(
+    @SerialName("results")
+    val results: List<Result>
+) {
+    @Serializable
+    data class Result(
+        @SerialName("longitude")
+        override val longitude: Double,
+        @SerialName("latitude")
+        override val latitude: Double,
+        @SerialName("elevation")
+        override val altitude: Double,
+    ) : IGeoPoint
+}

icegps-shared/src/main/java/com/icegps/shared/api/OpenElevationApi.kt

@@ -0,0 +1,35 @@
+package com.icegps.shared.api
+
+import com.icegps.shared.model.IGeoPoint
+import io.ktor.client.HttpClient
+import io.ktor.client.call.body
+import io.ktor.client.request.get
+import io.ktor.client.request.parameter
+import io.ktor.http.appendPathSegments
+
+/**
+ * @author tabidachinokaze
+ * @date 2025/11/20
+ */
+interface OpenElevationApi {
+    suspend fun lookup(values: List<IGeoPoint>): List<IGeoPoint>
+}
+
+class OpenElevation(
+    private val client: HttpClient
+) : OpenElevationApi {
+    private val baseUrl: String = "https://api.open-elevation.com/api/v1/"
+
+    // curl 'https://api.open-elevation.com/api/v1/lookup?locations=10,10|20,20|41.161758,-8.583933'
+    override suspend fun lookup(values: List<IGeoPoint>): List<IGeoPoint> {
+        val response = client.get(baseUrl) {
+            url {
+                appendPathSegments("lookup")
+                parameter(
+                    "locations",
+                    values.joinToString("|") { "${it.latitude},${it.longitude}" })
+            }
+        }
+        return response.body<LookupResponse>().results
+    }
+}

icegps-shared/src/main/java/com/icegps/shared/ktx/Any.kt

@@ -0,0 +1,7 @@
+package com.icegps.shared.ktx
+
+/**
+ * @author tabidachinokaze
+ * @date 2025/11/22
+ */
+val Any.TAG: String get() = this::class.java.simpleName

icegps-shared/src/main/java/com/icegps/shared/model/GeoPoint.kt

@@ -0,0 +1,11 @@
+package com.icegps.shared.model
+
+/**
+ * @author tabidachinokaze
+ * @date 2025/11/22
+ */
+data class GeoPoint(
+    override val longitude: Double,
+    override val latitude: Double,
+    override val altitude: Double
+) : IGeoPoint

icegps-shared/src/main/java/com/icegps/shared/model/IGeoPoint.kt

@@ -0,0 +1,11 @@
+package com.icegps.shared.model
+
+/**
+ * @author tabidachinokaze
+ * @date 2025/11/22
+ */
+interface IGeoPoint {
+    val longitude: Double
+    val latitude: Double
+    val altitude: Double
+}

icegps-shared/src/test/java/com/icegps/shared/ExampleUnitTest.kt

@@ -0,0 +1,17 @@
+package com.icegps.shared
+
+import org.junit.Test
+
+import org.junit.Assert.*
+
+/**
+ * Example local unit test, which will execute on the development machine (host).
+ *
+ * See [testing documentation](http://d.android.com/tools/testing).
+ */
+class ExampleUnitTest {
+    @Test
+    fun addition_isCorrect() {
+        assertEquals(4, 2 + 2)
+    }
+}

icegps-triangulation/.gitignore

@@ -0,0 +1 @@
+/build

icegps-triangulation/build.gradle.kts

@@ -0,0 +1,16 @@
+plugins {
+    id("java-library")
+    alias(libs.plugins.kotlin.jvm)
+}
+java {
+    sourceCompatibility = JavaVersion.VERSION_17
+    targetCompatibility = JavaVersion.VERSION_17
+}
+kotlin {
+    compilerOptions {
+        jvmTarget = org.jetbrains.kotlin.gradle.dsl.JvmTarget.JVM_17
+    }
+}
+dependencies {
+    implementation(project(":math"))
+}

icegps-triangulation/src/main/java/com/icegps/triangulation/Delaunator.kt

@@ -0,0 +1,596 @@
+package com.icegps.triangulation
+
+import kotlin.math.*
+
+val EPSILON: Double = 2.0.pow(-52)
+
+/**
+ * A Kotlin port of Mapbox's Delaunator incredibly fast JavaScript library for Delaunay triangulation of 2D points.
+ *
+ * @description Port of Mapbox's Delaunator (JavaScript) library - https://github.com/mapbox/delaunator
+ * @property coords flat positions' array - [x0, y0, x1, y1..]
+ *
+ * @since f0ed80d - commit
+ * @author Ricardo Matias
+ */
+@Suppress("unused")
+class Delaunator(val coords: DoubleArray) {
+    val EDGE_STACK = IntArray(512)
+
+    private var count = coords.size shr 1
+
+    // arrays that will store the triangulation graph
+    val maxTriangles = (2 * count - 5).coerceAtLeast(0)
+    private val _triangles = IntArray(maxTriangles * 3)
+    private val _halfedges = IntArray(maxTriangles * 3)
+
+    lateinit var triangles: IntArray
+    lateinit var halfedges: IntArray
+
+    // temporary arrays for tracking the edges of the advancing convex hull
+    private var hashSize = ceil(sqrt(count * 1.0)).toInt()
+    private var hullPrev = IntArray(count) // edge to prev edge
+    private var hullNext = IntArray(count) // edge to next edge
+    private var hullTri = IntArray(count) // edge to adjacent triangle
+    private var hullHash = IntArray(hashSize) // angular edge hash
+    private var hullStart: Int = -1
+
+    // temporary arrays for sorting points
+    private var ids = IntArray(count)
+    private var dists = DoubleArray(count)
+
+    private var cx: Double = Double.NaN
+    private var cy: Double = Double.NaN
+
+    private var trianglesLen: Int = -1
+
+    lateinit var hull: IntArray
+
+    init {
+        update()
+    }
+
+    fun update() {
+        if (coords.size <= 2) {
+            halfedges = IntArray(0)
+            triangles = IntArray(0)
+            hull = IntArray(0)
+            return
+        }
+
+
+        // populate an array of point indices calculate input data bbox
+        var minX = Double.POSITIVE_INFINITY
+        var minY = Double.POSITIVE_INFINITY
+        var maxX = Double.NEGATIVE_INFINITY
+        var maxY = Double.NEGATIVE_INFINITY
+
+        // points -> points
+        // minX, minY, maxX, maxY
+        for (i in 0 until count) {
+            val x = coords[2 * i]
+            val y = coords[2 * i + 1]
+            if (x < minX) minX = x
+            if (y < minY) minY = y
+            if (x > maxX) maxX = x
+            if (y > maxY) maxY = y
+
+            ids[i] = i
+        }
+
+        val cx = (minX + maxX) / 2
+        val cy = (minY + maxY) / 2
+
+        var minDist = Double.POSITIVE_INFINITY
+
+        var i0: Int = -1
+        var i1: Int = -1
+        var i2: Int = -1
+
+        // pick a seed point close to the center
+        for (i in 0 until count) {
+            val d = dist(cx, cy, coords[2 * i], coords[2 * i + 1])
+
+            if (d < minDist) {
+                i0 = i
+                minDist = d
+            }
+        }
+
+        val i0x = coords[2 * i0]
+        val i0y = coords[2 * i0 + 1]
+
+        minDist = Double.POSITIVE_INFINITY
+
+        // Find the point closest to the seed
+        for(i in 0 until count) {
+            if (i == i0) continue
+
+            val d = dist(i0x, i0y, coords[2 * i], coords[2 * i + 1])
+
+            if (d < minDist && d > 0) {
+                i1 = i
+                minDist = d
+            }
+        }
+
+        var i1x = coords[2 * i1]
+        var i1y = coords[2 * i1 + 1]
+
+        var minRadius = Double.POSITIVE_INFINITY
+
+        // Find the third point which forms the smallest circumcircle with the first two
+        for (i in 0 until count) {
+            if(i == i0 || i == i1) continue
+
+            val r = circumradius(i0x, i0y, i1x, i1y, coords[2 * i], coords[2 * i + 1])
+
+            if(r < minRadius) {
+                i2 = i
+                minRadius = r
+            }
+        }
+
+        if (minRadius == Double.POSITIVE_INFINITY) {
+            // order collinear points by dx (or dy if all x are identical)
+            // and return the list as a hull
+            for (i in 0 until count) {
+                val a = (coords[2 * i] - coords[0])
+                val b = (coords[2 * i + 1] - coords[1])
+                dists[i] =  if (a == 0.0) b else a
+            }
+
+            quicksort(ids, dists, 0, count - 1)
+
+            val nhull = IntArray(count)
+            var j = 0
+            var d0 = Double.NEGATIVE_INFINITY
+
+            for (i in 0 until count) {
+                val id = ids[i]
+                if (dists[id] > d0) {
+                    nhull[j++] = id
+                    d0 = dists[id]
+                }
+            }
+
+            hull = nhull.copyOf(j)
+            triangles = IntArray(0)
+            halfedges = IntArray(0)
+
+            return
+        }
+
+        var i2x = coords[2 * i2]
+        var i2y = coords[2 * i2 + 1]
+
+        // swap the order of the seed points for counter-clockwise orientation
+        if (orient2d(i0x, i0y, i1x, i1y, i2x, i2y) < 0.0) {
+            val i = i1
+            val x = i1x
+            val y = i1y
+            i1 = i2
+            i1x = i2x
+            i1y = i2y
+            i2 = i
+            i2x = x
+            i2y = y
+        }
+
+
+        val center = circumcenter(i0x, i0y, i1x, i1y, i2x, i2y)
+
+        this.cx = center[0]
+        this.cy = center[1]
+
+        for (i in 0 until count) {
+            dists[i] = dist(coords[2 * i], coords[2 * i + 1], center[0], center[1])
+        }
+
+        // sort the points by distance from the seed triangle circumcenter
+        quicksort(ids, dists, 0, count - 1)
+
+        // set up the seed triangle as the starting hull
+        hullStart = i0
+        var hullSize = 3
+
+        hullNext[i0] = i1
+        hullNext[i1] = i2
+        hullNext[i2] = i0
+
+        hullPrev[i2] = i1
+        hullPrev[i0] = i2
+        hullPrev[i1] = i0
+
+        hullTri[i0] = 0
+        hullTri[i1] = 1
+        hullTri[i2] = 2
+
+        hullHash.fill(-1)
+        hullHash[hashKey(i0x, i0y)] = i0
+        hullHash[hashKey(i1x, i1y)] = i1
+        hullHash[hashKey(i2x, i2y)] = i2
+
+        trianglesLen = 0
+        addTriangle(i0, i1, i2, -1, -1, -1)
+
+        var xp = 0.0
+        var yp = 0.0
+
+        for (k in ids.indices) {
+            val i = ids[k]
+            val x = coords[2 * i]
+            val y = coords[2 * i + 1]
+
+            // skip near-duplicate points
+            if (k > 0 && abs(x - xp) <= EPSILON && abs(y - yp) <= EPSILON) continue
+
+            xp = x
+            yp = y
+
+            // skip seed triangle points
+            if (i == i0 || i == i1 || i == i2) continue
+
+            // find a visible edge on the convex hull using edge hash
+            var start = 0
+            val key = hashKey(x, y)
+
+            for (j in 0 until hashSize) {
+                start = hullHash[(key + j) % hashSize]
+
+                if (start != -1 && start != hullNext[start]) break
+            }
+
+            start = hullPrev[start]
+
+            var e = start
+            var q = hullNext[e]
+
+            while (orient2d(x, y, coords[2 * e], coords[2 * e + 1], coords[2 * q], coords[2 * q + 1]) >= 0) {
+                e = q
+
+                if (e == start) {
+                    e = -1
+                    break
+                }
+
+                q = hullNext[e]
+            }
+
+            if (e == -1) continue // likely a near-duplicate point skip it
+
+            // add the first triangle from the point
+            var t = addTriangle(e, i, hullNext[e], -1, -1, hullTri[e])
+
+            // recursively flip triangles from the point until they satisfy the Delaunay condition
+            hullTri[i] = legalize(t + 2)
+            hullTri[e] = t // keep track of boundary triangles on the hull
+            hullSize++
+
+            // walk forward through the hull, adding more triangles and flipping recursively
+            var next = hullNext[e]
+            q = hullNext[next]
+
+            while (orient2d(x, y, coords[2 * next], coords[2 * next + 1], coords[2 * q], coords[2 * q + 1]) < 0) {
+                t = addTriangle(next, i, q, hullTri[i], -1, hullTri[next])
+                hullTri[i] = legalize(t + 2)
+                hullNext[next] = next // mark as removed
+                hullSize--
+
+                next = q
+                q = hullNext[next]
+            }
+
+            // walk backward from the other side, adding more triangles and flipping
+            if (e == start) {
+                q = hullPrev[e]
+
+                while (orient2d(x, y, coords[2 * q], coords[2 * q + 1], coords[2 * e], coords[2 * e + 1]) < 0) {
+                    t = addTriangle(q, i, e, -1, hullTri[e], hullTri[q])
+                    legalize(t + 2)
+                    hullTri[q] = t
+                    hullNext[e] = e // mark as removed
+                    hullSize--
+
+                    e = q
+                    q = hullPrev[e]
+                }
+            }
+
+            // update the hull indices
+            hullStart = e
+            hullPrev[i] = e
+
+            hullNext[e] = i
+            hullPrev[next] = i
+            hullNext[i] = next
+
+            // save the two new edges in the hash table
+            hullHash[hashKey(x, y)] = i
+            hullHash[hashKey(coords[2 * e], coords[2 * e + 1])] = e
+        }
+
+        hull = IntArray(hullSize)
+
+        var e = hullStart
+
+        for (i in 0 until hullSize) {
+            hull[i] = e
+            e = hullNext[e]
+        }
+
+        // trim typed triangle mesh arrays
+        triangles = _triangles.copyOf(trianglesLen)
+        halfedges = _halfedges.copyOf(trianglesLen)
+    }
+
+    private fun legalize(a: Int): Int {
+        var i = 0
+        var na = a
+        var ar: Int
+
+        // recursion eliminated with a fixed-size stack
+        while (true) {
+            val b = _halfedges[na]
+
+            /* if the pair of triangles doesn't satisfy the Delaunay condition
+             * (p1 is inside the circumcircle of [p0, pl, pr]), flip them,
+             * then do the same check/flip recursively for the new pair of triangles
+             *
+             *           pl                    pl
+             *          /||\                  /  \
+             *       al/ || \bl            al/    \a
+             *        /  ||  \              /      \
+             *       /  a||b  \    flip    /___ar___\
+             *     p0\   ||   /p1   =>   p0\---bl---/p1
+             *        \  ||  /              \      /
+             *       ar\ || /br             b\    /br
+             *          \||/                  \  /
+             *           pr                    pr
+             */
+            val a0 = na - na % 3
+            ar = a0 + (na + 2) % 3
+
+            if (b == -1) { // convex hull edge
+                if (i == 0) break
+                na = EDGE_STACK[--i]
+                continue
+            }
+
+            val b0 = b - b % 3
+            val al = a0 + (na + 1) % 3
+            val bl = b0 + (b + 2) % 3
+
+            val p0 = _triangles[ar]
+            val pr = _triangles[na]
+            val pl = _triangles[al]
+            val p1 = _triangles[bl]
+
+            val illegal = inCircleRobust(
+                coords[2 * p0], coords[2 * p0 + 1],
+                coords[2 * pr], coords[2 * pr + 1],
+                coords[2 * pl], coords[2 * pl + 1],
+                coords[2 * p1], coords[2 * p1 + 1])
+
+            if (illegal) {
+                _triangles[na] = p1
+                _triangles[b] = p0
+
+                val hbl = _halfedges[bl]
+
+                // edge swapped on the other side of the hull (rare) fix the halfedge reference
+                if (hbl == -1) {
+                    var e = hullStart
+                    do {
+                        if (hullTri[e] == bl) {
+                            hullTri[e] = na
+                            break
+                        }
+                        e = hullPrev[e]
+                    } while (e != hullStart)
+                }
+                link(na, hbl)
+                link(b, _halfedges[ar])
+                link(ar, bl)
+
+                val br = b0 + (b + 1) % 3
+
+                // don't worry about hitting the cap: it can only happen on extremely degenerate input
+                if (i < EDGE_STACK.size) {
+                    EDGE_STACK[i++] = br
+                }
+            } else {
+                if (i == 0) break
+                na = EDGE_STACK[--i]
+            }
+        }
+
+        return ar
+
+    }
+
+    private fun link(a:Int, b:Int) {
+        _halfedges[a] = b
+        if (b != -1) _halfedges[b] = a
+    }
+
+    // add a new triangle given vertex indices and adjacent half-edge ids
+    private fun addTriangle(i0: Int, i1: Int, i2: Int, a: Int, b: Int, c: Int): Int {
+        val t = trianglesLen
+
+        _triangles[t] = i0
+        _triangles[t + 1] = i1
+        _triangles[t + 2] = i2
+
+        link(t, a)
+        link(t + 1, b)
+        link(t + 2, c)
+
+        trianglesLen += 3
+
+        return t
+    }
+
+    private fun hashKey(x: Double, y: Double): Int {
+        return (floor(pseudoAngle(x - cx, y - cy) * hashSize) % hashSize).toInt()
+    }
+}
+
+fun circumradius(ax: Double, ay: Double,
+                 bx: Double, by: Double,
+                 cx: Double, cy: Double): Double {
+    val dx = bx - ax
+    val dy = by - ay
+    val ex = cx - ax
+    val ey = cy - ay
+
+    val bl = dx * dx + dy * dy
+    val cl = ex * ex + ey * ey
+    val d = 0.5 / (dx * ey - dy * ex)
+
+    val x = (ey * bl - dy * cl) * d
+    val y = (dx * cl - ex * bl) * d
+
+    return x * x + y * y
+}
+
+fun circumcenter(ax: Double, ay: Double,
+                 bx: Double, by: Double,
+                 cx: Double, cy: Double): DoubleArray {
+    val dx = bx - ax
+    val dy = by - ay
+    val ex = cx - ax
+    val ey = cy - ay
+
+    val bl = dx * dx + dy * dy
+    val cl = ex * ex + ey * ey
+    val d = 0.5 / (dx * ey - dy * ex)
+
+    val x = ax + (ey * bl - dy * cl) * d
+    val y = ay + (dx * cl - ex * bl) * d
+
+    return doubleArrayOf(x, y)
+}
+
+fun quicksort(ids: IntArray, dists: DoubleArray, left: Int, right: Int) {
+    if (right - left <= 20) {
+        for (i in (left + 1)..right) {
+            val temp = ids[i]
+            val tempDist = dists[temp]
+            var j = i - 1
+            while (j >= left && dists[ids[j]] > tempDist) ids[j + 1] = ids[j--]
+            ids[j + 1] = temp
+        }
+    } else {
+        val median = (left + right) shr 1
+        var i = left + 1
+        var j = right
+
+        swap(ids, median, i)
+
+        if (dists[ids[left]] > dists[ids[right]]) swap(ids, left, right)
+        if (dists[ids[i]] > dists[ids[right]]) swap(ids, i, right)
+        if (dists[ids[left]] > dists[ids[i]]) swap(ids, left, i)
+
+        val temp = ids[i]
+        val tempDist = dists[temp]
+
+        while (true) {
+            do i++ while (dists[ids[i]] < tempDist)
+            do j-- while (dists[ids[j]] > tempDist)
+            if (j < i) break
+            swap(ids, i, j)
+        }
+
+        ids[left + 1] = ids[j]
+        ids[j] = temp
+
+        if (right - i + 1 >= j - left) {
+            quicksort(ids, dists, i, right)
+            quicksort(ids, dists, left, j - 1)
+        } else {
+            quicksort(ids, dists, left, j - 1)
+            quicksort(ids, dists, i, right)
+        }
+    }
+}
+
+private fun swap(arr: IntArray, i: Int, j: Int) {
+    val tmp = arr[i]
+    arr[i] = arr[j]
+    arr[j] = tmp
+}
+
+// monotonically increases with real angle, but doesn't need expensive trigonometry
+private fun pseudoAngle(dx: Double, dy: Double): Double {
+    val p = dx / (abs(dx) + abs(dy))
+    val a =  if (dy > 0.0) 3.0 - p else 1.0 + p
+
+    return a / 4.0 // [0..1]
+}
+
+private fun inCircle(ax: Double, ay: Double,
+                     bx: Double, by: Double,
+                     cx: Double, cy: Double,
+                     px: Double, py: Double): Boolean {
+    val dx = ax - px
+    val dy = ay - py
+    val ex = bx - px
+    val ey = by - py
+    val fx = cx - px
+    val fy = cy - py
+
+    val ap = dx * dx + dy * dy
+    val bp = ex * ex + ey * ey
+    val cp = fx * fx + fy * fy
+
+    return dx * (ey * cp - bp * fy) -
+            dy * (ex * cp - bp * fx) +
+            ap * (ex * fy - ey * fx) < 0
+}
+
+private fun inCircleRobust(
+    ax: Double, ay: Double,
+    bx: Double, by: Double,
+    cx: Double, cy: Double,
+    px: Double, py: Double
+): Boolean {
+
+    val dx = twoDiff(ax, px)
+    val dy = twoDiff(ay, py)
+    val ex = twoDiff(bx, px)
+    val ey = twoDiff(by, py)
+    val fx = twoDiff(cx, px)
+    val fy = twoDiff(cy, py)
+
+    val ap = ddAddDd(ddMultDd(dx, dx), ddMultDd(dy, dy))
+    val bp = ddAddDd(ddMultDd(ex, ex), ddMultDd(ey, ey))
+    val cp = ddAddDd(ddMultDd(fx, fx), ddMultDd(fy, fy))
+
+    val dd = ddAddDd(
+        ddDiffDd(
+            ddMultDd(dx, ddDiffDd(ddMultDd(ey, cp), ddMultDd(bp, fy))),
+            ddMultDd(dy, ddDiffDd(ddMultDd(ex, cp), ddMultDd(bp, fx)))
+        ),
+        ddMultDd(ap, ddDiffDd(ddMultDd(ex, fy), ddMultDd(ey, fx)))
+    )
+    return (dd[1]) <= 0
+}
+
+
+private fun dist(ax: Double, ay: Double, bx: Double, by: Double): Double {
+    //val dx = ax - bx
+    //val dy = ay - by
+    //return dx * dx + dy * dy
+
+    // double-double implementation but I think it is overkill.
+
+    val dx = twoDiff(ax, bx)
+    val dy = twoDiff(ay, by)
+    val dx2 = ddMultDd(dx, dx)
+    val dy2 = ddMultDd(dy, dy)
+    val d2 = ddAddDd(dx2, dy2)
+
+    return d2[0] + d2[1]
+
+}

icegps-triangulation/src/main/java/com/icegps/triangulation/Delaunay.kt

@@ -0,0 +1,225 @@
+package com.icegps.triangulation
+
+import com.icegps.math.geometry.Vector2D
+import com.icegps.triangulation.Delaunay.Companion.from
+import kotlin.math.cos
+import kotlin.math.pow
+import kotlin.math.sin
+
+/*
+ISC License
+
+Copyright 2021 Ricardo Matias.
+
+Permission to use, copy, modify, and/or distribute this software for any purpose
+with or without fee is hereby granted, provided that the above copyright notice
+and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
+THIS SOFTWARE.
+*/
+
+/**
+ * Use [from] static method to use the delaunay triangulation
+ *
+ * @description Port of d3-delaunay (JavaScript) library - https://github.com/d3/d3-delaunay
+ * @property points flat positions' array - [x0, y0, x1, y1..]
+ *
+ * @since 9258fa3 - commit
+ * @author Ricardo Matias
+ */
+@Suppress("unused")
+class Delaunay(val points: DoubleArray) {
+    companion object {
+        /**
+         * Entry point for the delaunay triangulation
+         *
+         * @property points a list of 2D points
+         */
+        fun from(points: List<Vector2D>): Delaunay {
+            val n = points.size
+            val coords = DoubleArray(n * 2)
+
+            for (i in points.indices) {
+                val p = points[i]
+                coords[2 * i] = p.x
+                coords[2 * i + 1] = p.y
+            }
+
+            return Delaunay(coords)
+        }
+    }
+
+    private var delaunator: Delaunator = Delaunator(points)
+
+    val inedges = IntArray(points.size / 2)
+    private val hullIndex = IntArray(points.size / 2)
+
+    var halfedges: IntArray = delaunator.halfedges
+    var hull: IntArray = delaunator.hull
+    var triangles: IntArray = delaunator.triangles
+
+    init {
+        init()
+    }
+
+    fun update() {
+        delaunator.update()
+        init()
+    }
+
+    fun neighbors(i: Int) = sequence<Int> {
+        val e0 = inedges[i]
+        if (e0 != -1) {
+            var e = e0
+            var p0 = -1
+
+            loop@ do {
+                p0 = triangles[e]
+                yield(p0)
+                e = if (e % 3 == 2) e - 2 else e + 1
+                if (e == -1) {
+                    break@loop
+                }
+
+                if (triangles[e] != i) {
+                    break@loop
+                    //error("bad triangulation")
+                }
+                e = halfedges[e]
+
+                if (e == -1) {
+                    val p = hull[(hullIndex[i] + 1) % hull.size]
+                    if (p != p0) {
+                        yield(p)
+                    }
+                    break@loop
+                }
+            } while (e != e0)
+        }
+    }
+
+    fun collinear(): Boolean {
+        for (i in 0 until triangles.size step 3) {
+            val a = 2 * triangles[i]
+            val b = 2 * triangles[i + 1]
+            val c = 2 * triangles[i + 2]
+            val coords = points
+            val cross = (coords[c] - coords[a]) * (coords[b + 1] - coords[a + 1])
+            -(coords[b] - coords[a]) * (coords[c + 1] - coords[a + 1])
+            if (cross > 1e-10) return false;
+        }
+        return true
+    }
+
+    private fun jitter(x: Double, y: Double, r: Double): DoubleArray {
+        return doubleArrayOf(x + sin(x + y) * r, y + cos(x - y) * r)
+    }
+
+    fun init() {
+
+        if (hull.size > 2 && collinear()) {
+            println("warning: triangulation is collinear")
+            val r = 1E-8
+            for (i in 0 until points.size step 2) {
+                val p = jitter(points[i], points[i + 1], r)
+                points[i] = p[0]
+                points[i + 1] = p[1]
+            }
+
+            delaunator = Delaunator(points)
+            halfedges = delaunator.halfedges
+            hull = delaunator.hull
+            triangles = delaunator.triangles
+
+        }
+
+
+
+        inedges.fill(-1)
+        hullIndex.fill(-1)
+
+        // Compute an index from each point to an (arbitrary) incoming halfedge
+        // Used to give the first neighbor of each point for this reason,
+        // on the hull we give priority to exterior halfedges
+        for (e in halfedges.indices) {
+            val p = triangles[nextHalfedge(e)]
+
+            if (halfedges[e] == -1 || inedges[p] == -1) inedges[p] = e
+        }
+
+        for (i in hull.indices) {
+            hullIndex[hull[i]] = i
+        }
+
+        // degenerate case: 1 or 2 (distinct) points
+        if (hull.size in 1..2) {
+            triangles = IntArray(3) { -1 }
+            halfedges = IntArray(3) { -1 }
+            triangles[0] = hull[0]
+            inedges[hull[0]] = 1
+            if (hull.size == 2) {
+                inedges[hull[1]] = 0
+                triangles[1] = hull[1]
+                triangles[2] = hull[1]
+            }
+        }
+    }
+
+
+    fun find(x: Double, y: Double, i: Int = 0): Int {
+        var i1 = i
+        var c = step(i, x, y)
+
+        while (c >= 0 && c != i && c != i1) {
+            i1 = c
+            c = step(i1, x, y)
+        }
+        return c
+    }
+
+    fun nextHalfedge(e: Int) = if (e % 3 == 2) e - 2 else e + 1
+    fun prevHalfedge(e: Int) = if (e % 3 == 0) e + 2 else e - 1
+
+    fun step(i: Int, x: Double, y: Double): Int {
+        if (inedges[i] == -1 || points.isEmpty()) return (i + 1) % (points.size shr 1)
+
+        var c = i
+        var dc = (x - points[i * 2]).pow(2) + (y - points[i * 2 + 1]).pow(2)
+        val e0 = inedges[i]
+        var e = e0
+        do {
+            val t = triangles[e]
+            val dt = (x - points[t * 2]).pow(2) + (y - points[t * 2 + 1]).pow(2)
+
+            if (dt < dc) {
+                dc = dt
+                c = t
+            }
+
+            e = if (e % 3 == 2) e - 2 else e + 1
+
+            if (triangles[e] != i) {
+                //error("bad triangulation")
+                break
+            } // bad triangulation
+
+            e = halfedges[e]
+
+            if (e == -1) {
+                e = hull[(hullIndex[i] + 1) % hull.size]
+                if (e != t) {
+                    if ((x - points[e * 2]).pow(2) + (y - points[e * 2 + 1]).pow(2) < dc) return e
+                }
+                break
+            }
+        } while (e != e0)
+
+        return c
+    }
+}

icegps-triangulation/src/main/java/com/icegps/triangulation/DelaunayTriangulation.kt

@@ -0,0 +1,69 @@
+package com.icegps.triangulation
+
+import com.icegps.math.geometry.Vector3D
+import com.icegps.math.geometry.toVector2D
+
+/**
+ * Kotlin/OPENRNDR idiomatic interface to `Delaunay`
+ */
+class DelaunayTriangulation(val points: List<Vector3D>) {
+    val delaunay: Delaunay = Delaunay.from(points.map { it.toVector2D() })
+
+    fun neighbors(pointIndex: Int): Sequence<Int> {
+        return delaunay.neighbors(pointIndex)
+    }
+
+    fun neighborPoints(pointIndex: Int): List<Vector3D> {
+        return neighbors(pointIndex).map { points[it] }.toList()
+    }
+
+    fun triangleIndices(): List<IntArray> {
+        val list = mutableListOf<IntArray>()
+        for (i in delaunay.triangles.indices step 3) {
+            list.add(
+                intArrayOf(
+                    delaunay.triangles[i],
+                    delaunay.triangles[i + 1],
+                    delaunay.triangles[i + 2]
+                )
+            )
+        }
+        return list
+    }
+
+    fun triangles(filterPredicate: (Int, Int, Int) -> Boolean = { _, _, _ -> true }): List<Triangle> {
+        val list = mutableListOf<Triangle>()
+
+        for (i in delaunay.triangles.indices step 3) {
+            val t0 = delaunay.triangles[i]
+            val t1 = delaunay.triangles[i + 1]
+            val t2 = delaunay.triangles[i + 2]
+
+            // originally they are defined *counterclockwise*
+            if (filterPredicate(t2, t1, t0)) {
+                val p1 = points[t0]
+                val p2 = points[t1]
+                val p3 = points[t2]
+                list.add(Triangle(p3, p2, p1))
+            }
+        }
+        return list
+    }
+
+    fun nearest(query: Vector3D): Int = delaunay.find(query.x, query.y)
+
+    fun nearestPoint(query: Vector3D): Vector3D = points[nearest(query)]
+}
+
+/**
+ * Computes the Delaunay triangulation for the list of 2D points.
+ *
+ * The Delaunay triangulation is a triangulation of a set of points such that
+ * no point is inside the circumcircle of any triangle. It maximizes the minimum
+ * angle of all the angles in the triangles, avoiding skinny triangles.
+ *
+ * @return A DelaunayTriangulation object representing the triangulation of the given points.
+ */
+fun List<Vector3D>.delaunayTriangulation(): DelaunayTriangulation {
+    return DelaunayTriangulation(this)
+}

icegps-triangulation/src/main/java/com/icegps/triangulation/DoubleDouble.kt

@@ -0,0 +1,340 @@
+package com.icegps.triangulation
+
+import kotlin.math.pow
+
+// original code: https://github.com/FlorisSteenkamp/double-double/
+
+
+/**
+ * Returns the difference and exact error of subtracting two floating point
+ * numbers.
+ * Uses an EFT (error-free transformation), i.e. `a-b === x+y` exactly.
+ * The returned result is a non-overlapping expansion (smallest value first!).
+ *
+ * * **precondition:** `abs(a) >= abs(b)` - A fast test that can be used is
+ * `(a > b) === (a > -b)`
+ *
+ * See https://people.eecs.berkeley.edu/~jrs/papers/robustr.pdf
+ */
+fun fastTwoDiff(a: Double, b: Double): DoubleArray {
+    val x = a - b;
+    val y = (a - x) - b;
+
+    return doubleArrayOf(y, x)
+}
+
+/**
+ * Returns the sum and exact error of adding two floating point numbers.
+ * Uses an EFT (error-free transformation), i.e. a+b === x+y exactly.
+ * The returned sum is a non-overlapping expansion (smallest value first!).
+ *
+ * Precondition: abs(a) >= abs(b) - A fast test that can be used is
+ * (a > b) === (a > -b)
+ *
+ * See https://people.eecs.berkeley.edu/~jrs/papers/robustr.pdf
+ */
+fun fastTwoSum(a: Double, b: Double): DoubleArray {
+    val x = a + b;
+
+    return doubleArrayOf(b - (x - a), x)
+}
+
+
+/**
+ * Truncates a floating point value's significand and returns the result.
+ * Similar to split, but with the ability to specify the number of bits to keep.
+ *
+ * **Theorem 17 (Veltkamp-Dekker)**: Let a be a p-bit floating-point number, where
+ * p >= 3. Choose a splitting point s such that p/2 <= s <= p-1. Then the
+ * following algorithm will produce a (p-s)-bit value a_hi and a
+ * nonoverlapping (s-1)-bit value a_lo such that abs(a_hi) >= abs(a_lo) and
+ * a = a_hi + a_lo.
+ *
+ * * see [Shewchuk](https://people.eecs.berkeley.edu/~jrs/papers/robustr.pdf)
+ *
+ * @param a a double
+ * @param bits the number of significand bits to leave intact
+ */
+fun reduceSignificand(
+    a: Double,
+    bits: Int
+): Double {
+
+    val s = 53 - bits;
+    val f = 2.0.pow(s) + 1;
+
+    val c = f * a;
+    val r = c - (c - a);
+
+    return r;
+}
+
+
+/**
+ * === 2^Math.ceil(p/2) + 1 where p is the # of significand bits in a double === 53.
+ * @internal
+ */
+const val f = 134217729;  // 2**27 + 1;
+
+
+/**
+ * Returns the result of splitting a double into 2 26-bit doubles.
+ *
+ * Theorem 17 (Veltkamp-Dekker): Let a be a p-bit floating-point number, where
+ * p >= 3. Choose a splitting point s such that p/2 <= s <= p-1. Then the
+ * following algorithm will produce a (p-s)-bit value a_hi and a
+ * nonoverlapping (s-1)-bit value a_lo such that abs(a_hi) >= abs(a_lo) and
+ * a = a_hi + a_lo.
+ *
+ * see e.g. [Shewchuk](https://people.eecs.berkeley.edu/~jrs/papers/robustr.pdf)
+ * @param a A double floating point number
+ */
+fun split(a: Double): DoubleArray {
+    val c = f * a;
+    val a_h = c - (c - a);
+    val a_l = a - a_h;
+
+    return doubleArrayOf(a_h, a_l)
+}
+
+/**
+ * Returns the exact result of subtracting b from a.
+ *
+ * @param a minuend - a double-double precision floating point number
+ * @param b subtrahend - a double-double precision floating point number
+ */
+fun twoDiff(a: Double, b: Double): DoubleArray {
+    val x = a - b;
+    val bvirt = a - x;
+    val y = (a - (x + bvirt)) + (bvirt - b);
+
+    return doubleArrayOf(y, x)
+}
+
+/**
+ * Returns the exact result of multiplying two doubles.
+ *
+ * * the resulting array is the reverse of the standard twoSum in the literature.
+ *
+ * Theorem 18 (Shewchuk): Let a and b be p-bit floating-point numbers, where
+ * p >= 6. Then the following algorithm will produce a nonoverlapping expansion
+ * x + y such that ab = x + y, where x is an approximation to ab and y
+ * represents the roundoff error in the calculation of x. Furthermore, if
+ * round-to-even tiebreaking is used, x and y are non-adjacent.
+ *
+ * See https://people.eecs.berkeley.edu/~jrs/papers/robustr.pdf
+ * @param a A double
+ * @param b Another double
+ */
+fun twoProduct(a: Double, b: Double): DoubleArray {
+    val x = a * b;
+
+    //const [ah, al] = split(a);
+    val c = f * a;
+    val ah = c - (c - a);
+    val al = a - ah;
+    //const [bh, bl] = split(b);
+    val d = f * b;
+    val bh = d - (d - b);
+    val bl = b - bh;
+
+    val y = (al * bl) - ((x - (ah * bh)) - (al * bh) - (ah * bl));
+
+    //const err1 = x - (ah * bh);
+    //const err2 = err1 - (al * bh);
+    //const err3 = err2 - (ah * bl);
+    //const y = (al * bl) - err3;
+
+    return doubleArrayOf(y, x)
+}
+
+fun twoSquare(a: Double): DoubleArray {
+    val x = a * a;
+
+    //const [ah, al] = split(a);
+    val c = f * a;
+    val ah = c - (c - a);
+    val al = a - ah;
+
+    val y = (al * al) - ((x - (ah * ah)) - 2 * (ah * al));
+
+    return doubleArrayOf(y, x)
+}
+
+/**
+ * Returns the exact result of adding two doubles.
+ *
+ * * the resulting array is the reverse of the standard twoSum in the literature.
+ *
+ * Theorem 7 (Knuth): Let a and b be p-bit floating-point numbers. Then the
+ * following algorithm will produce a nonoverlapping expansion x + y such that
+ * a + b = x + y, where x is an approximation to a + b and y is the roundoff
+ * error in the calculation of x.
+ *
+ * See https://people.eecs.berkeley.edu/~jrs/papers/robustr.pdf
+ */
+fun twoSum(a: Double, b: Double): DoubleArray {
+    val x = a + b;
+    val bv = x - a;
+
+    return doubleArrayOf((a - (x - bv)) + (b - bv), x)
+}
+
+/**
+ * Returns the result of subtracting the second given double-double-precision
+ * floating point number from the first.
+ *
+ * * relative error bound: 3u^2 + 13u^3, i.e. fl(a-b) = (a-b)(1+ϵ),
+ * where ϵ <= 3u^2 + 13u^3, u = 0.5 * Number.EPSILON
+ * * the error bound is not sharp - the worst case that could be found by the
+ * authors were 2.25u^2
+ *
+ * ALGORITHM 6 of https://hal.archives-ouvertes.fr/hal-01351529v3/document
+ * @param x a double-double precision floating point number
+ * @param y another double-double precision floating point number
+ */
+fun ddDiffDd(x: DoubleArray, y: DoubleArray): DoubleArray {
+    val xl = x[0];
+    val xh = x[1];
+    val yl = y[0];
+    val yh = y[1];
+
+    //const [sl,sh] = twoSum(xh,yh);
+    val sh = xh - yh;
+    val _1 = sh - xh;
+    val sl = (xh - (sh - _1)) + (-yh - _1);
+    //const [tl,th] = twoSum(xl,yl);
+    val th = xl - yl;
+    val _2 = th - xl;
+    val tl = (xl - (th - _2)) + (-yl - _2);
+    val c = sl + th;
+    //const [vl,vh] = fastTwoSum(sh,c)
+    val vh = sh + c;
+    val vl = c - (vh - sh);
+    val w = tl + vl
+    //const [zl,zh] = fastTwoSum(vh,w)
+    val zh = vh + w;
+    val zl = w - (zh - vh);
+
+    return doubleArrayOf(zl, zh)
+}
+
+/**
+ * Returns the product of two double-double-precision floating point numbers.
+ *
+ * * relative error bound: 7u^2, i.e. fl(a+b) = (a+b)(1+ϵ),
+ * where ϵ <= 7u^2, u = 0.5 * Number.EPSILON
+ * the error bound is not sharp - the worst case that could be found by the
+ * authors were 5u^2
+ *
+ * * ALGORITHM 10 of https://hal.archives-ouvertes.fr/hal-01351529v3/document
+ * @param x a double-double precision floating point number
+ * @param y another double-double precision floating point number
+ */
+fun ddMultDd(x: DoubleArray, y: DoubleArray): DoubleArray {
+
+
+    //const xl = x[0];
+    val xh = x[1];
+    //const yl = y[0];
+    val yh = y[1];
+
+    //const [cl1,ch] = twoProduct(xh,yh);
+    val ch = xh * yh;
+    val c = f * xh;
+    val ah = c - (c - xh);
+    val al = xh - ah;
+    val d = f * yh;
+    val bh = d - (d - yh);
+    val bl = yh - bh;
+    val cl1 = (al * bl) - ((ch - (ah * bh)) - (al * bh) - (ah * bl));
+
+    //return fastTwoSum(ch,cl1 + (xh*yl + xl*yh));
+    val b = cl1 + (xh * y[0] + x[0] * yh);
+    val xx = ch + b;
+
+    return doubleArrayOf(b - (xx - ch), xx)
+}
+
+
+/**
+ * Returns the result of adding two double-double-precision floating point
+ * numbers.
+ *
+ * * relative error bound: 3u^2 + 13u^3, i.e. fl(a+b) = (a+b)(1+ϵ),
+ * where ϵ <= 3u^2 + 13u^3, u = 0.5 * Number.EPSILON
+ * * the error bound is not sharp - the worst case that could be found by the
+ * authors were 2.25u^2
+ *
+ * ALGORITHM 6 of https://hal.archives-ouvertes.fr/hal-01351529v3/document
+ * @param x a double-double precision floating point number
+ * @param y another double-double precision floating point number
+ */
+fun ddAddDd(x: DoubleArray, y: DoubleArray): DoubleArray {
+    val xl = x[0];
+    val xh = x[1];
+    val yl = y[0];
+    val yh = y[1];
+
+    //const [sl,sh] = twoSum(xh,yh);
+    val sh = xh + yh;
+    val _1 = sh - xh;
+    val sl = (xh - (sh - _1)) + (yh - _1);
+    //val [tl,th] = twoSum(xl,yl);
+    val th = xl + yl;
+    val _2 = th - xl;
+    val tl = (xl - (th - _2)) + (yl - _2);
+    val c = sl + th;
+    //val [vl,vh] = fastTwoSum(sh,c)
+    val vh = sh + c;
+    val vl = c - (vh - sh);
+    val w = tl + vl
+    //val [zl,zh] = fastTwoSum(vh,w)
+    val zh = vh + w;
+    val zl = w - (zh - vh);
+
+    return doubleArrayOf(zl, zh)
+}
+
+
+/**
+ * Returns the product of a double-double-precision floating point number and a
+ * double.
+ *
+ * * slower than ALGORITHM 8 (one call to fastTwoSum more) but about 2x more
+ * accurate
+ * * relative error bound: 1.5u^2 + 4u^3, i.e. fl(a+b) = (a+b)(1+ϵ),
+ * where ϵ <= 1.5u^2 + 4u^3, u = 0.5 * Number.EPSILON
+ * * the bound is very sharp
+ * * probably prefer `ddMultDouble2` due to extra speed
+ *
+ * * ALGORITHM 7 of https://hal.archives-ouvertes.fr/hal-01351529v3/document
+ * @param y a double
+ * @param x a double-double precision floating point number
+ */
+fun ddMultDouble1(y: Double, x: DoubleArray): DoubleArray {
+    val xl = x[0];
+    val xh = x[1];
+
+    //val [cl1,ch] = twoProduct(xh,y);
+    val ch = xh * y;
+    val c = f * xh;
+    val ah = c - (c - xh);
+    val al = xh - ah;
+    val d = f * y;
+    val bh = d - (d - y);
+    val bl = y - bh;
+    val cl1 = (al * bl) - ((ch - (ah * bh)) - (al * bh) - (ah * bl));
+
+    val cl2 = xl * y;
+    //val [tl1,th] = fastTwoSum(ch,cl2);
+    val th = ch + cl2;
+    val tl1 = cl2 - (th - ch);
+
+    val tl2 = tl1 + cl1;
+    //val [zl,zh] = fastTwoSum(th,tl2);
+    val zh = th + tl2;
+    val zl = tl2 - (zh - th);
+
+    return doubleArrayOf(zl, zh);
+}

icegps-triangulation/src/main/java/com/icegps/triangulation/Predicates.kt

@@ -0,0 +1,19 @@
+package com.icegps.triangulation
+
+fun orient2d(bx: Double, by: Double, ax: Double, ay: Double, cx: Double, cy: Double): Double {
+    // (ax,ay) (bx,by) are swapped such that the sign of the determinant is flipped. which is what Delaunator.kt expects.
+
+    /*
+    | a  b | = | ax - cx  ay - cy |
+    | c  d |   | bx - cx  by - cy |
+    */
+
+    val a = twoDiff(ax, cx)
+    val b = twoDiff(ay, cy)
+    val c = twoDiff(bx, cx)
+    val d = twoDiff(by, cy)
+
+    val determinant = ddDiffDd(ddMultDd(a, d), ddMultDd(b, c))
+
+    return determinant[1]
+}

icegps-triangulation/src/main/java/com/icegps/triangulation/Triangle.kt

@@ -0,0 +1,13 @@
+package com.icegps.triangulation
+
+import com.icegps.math.geometry.Vector3D
+
+/**
+ * @author tabidachinokaze
+ * @date 2025/11/26
+ */
+data class Triangle(
+    val x1: Vector3D,
+    val x2: Vector3D,
+    val x3: Vector3D,
+)

math/.gitignore

@@ -0,0 +1 @@
+/build

math/build.gradle.kts

@@ -0,0 +1,13 @@
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+
+plugins {
+    alias(libs.plugins.kotlin.jvm)
+}
+
+java {
+    sourceCompatibility = JavaVersion.VERSION_17
+    targetCompatibility = JavaVersion.VERSION_17
+}
+kotlin {
+    compilerOptions.jvmTarget = JvmTarget.JVM_17
+}

math/src/main/java/com/icegps/io/util/NumberExt.kt

@@ -0,0 +1,75 @@
+@file:Suppress("NOTHING_TO_INLINE")
+
+package com.icegps.io.util
+
+import kotlin.math.*
+
+//private fun Double.normalizeZero(): Double = if (this.isAlmostZero()) 0.0 else this
+private val MINUS_ZERO_D = -0.0
+private fun Double.normalizeZero(): Double = if (this == MINUS_ZERO_D) 0.0 else this
+
+fun Double.toStringDecimal(decimalPlaces: Int, skipTrailingZeros: Boolean = false): String {
+    if (this.isNanOrInfinite()) return this.toString()
+
+    //val bits = this.toRawBits()
+    //val sign = (bits ushr 63) != 0L
+    //val exponent = (bits ushr 52) and 0b11111111111
+    //val fraction = bits and ((1L shl 52) - 1L)
+
+	val res = this.roundDecimalPlaces(decimalPlaces).normalizeZero().toString()
+
+	val eup = res.indexOf('E')
+	val elo = res.indexOf('e')
+    val eIndex = if (eup >= 0) eup else elo
+	val rez = if (eIndex >= 0) {
+        val base = res.substring(0, eIndex)
+        val exp = res.substring(eIndex + 1).toInt()
+        val rbase = if (base.contains(".")) base else "$base.0"
+        val zeros = "0".repeat(exp.absoluteValue + 2)
+		val part = if (exp > 0) "$rbase$zeros" else "$zeros$rbase"
+		val pointIndex2 = part.indexOf(".")
+        val pointIndex = if (pointIndex2 < 0) part.length else pointIndex2
+		val outIndex = pointIndex + exp
+		val part2 = part.replace(".", "")
+        buildString {
+            if ((0 until outIndex).all { part2[it] == '0' }) {
+                append('0')
+            } else {
+                append(part2, 0, outIndex)
+            }
+            append('.')
+            append(part2, outIndex, part2.length)
+        }
+	} else {
+		res
+	}
+
+    val pointIndex = rez.indexOf('.')
+	val integral = if (pointIndex >= 0) rez.substring(0, pointIndex) else rez
+    if (decimalPlaces == 0) return integral
+
+	val decimal = if (pointIndex >= 0) rez.substring(pointIndex + 1).trimEnd('0') else ""
+    return buildString(2 + integral.length + decimalPlaces) {
+        append(integral)
+        if (decimal.isNotEmpty() || !skipTrailingZeros) {
+            val decimalCount = min(decimal.length, decimalPlaces)
+            val allZeros = (0 until decimalCount).all { decimal[it] == '0' }
+            if (!skipTrailingZeros || !allZeros) {
+                append('.')
+                append(decimal, 0, decimalCount)
+                if (!skipTrailingZeros) repeat(decimalPlaces - decimalCount) { append('0') }
+            }
+        }
+    }
+}
+
+fun Float.toStringDecimal(decimalPlaces: Int, skipTrailingZeros: Boolean = false): String = this.toDouble().toStringDecimal(decimalPlaces, skipTrailingZeros)
+
+private fun Double.roundDecimalPlaces(places: Int): Double {
+    if (places < 0) return this
+    val placesFactor: Double = 10.0.pow(places.toDouble())
+    return round(this * placesFactor) / placesFactor
+}
+
+private fun Double.isNanOrInfinite() = this.isNaN() || this.isInfinite()
+private fun Float.isNanOrInfinite() = this.isNaN() || this.isInfinite()

math/src/main/java/com/icegps/io/util/NumberParser.kt

@@ -0,0 +1,78 @@
+package com.icegps.io.util
+
+import kotlin.math.*
+
+object NumberParser {
+	const val END = '\u0000'
+
+	fun parseInt(str: String, start: Int = 0, end: Int = str.length, radix: Int = 10): Int {
+		var n = start
+		return parseInt(radix) { if (n >= end) END else str[n++] }
+	}
+
+	fun parseDouble(str: String, start: Int = 0, end: Int = str.length): Double {
+		var n = start
+		return parseDouble { if (n >= end) END else str[n++] }
+	}
+
+	inline fun parseInt(radix: Int = 10, gen: (Int) -> Char): Int {
+		var positive = true
+		var out = 0
+		var n = 0
+		while (true) {
+			val c = gen(n++)
+			if (c == END) break
+			if (c == '-' || c == '+') {
+				positive = (c == '+')
+			} else {
+				val value = c.ctypeAsInt()
+				if (value < 0) break
+				out *= radix
+				out += value
+			}
+		}
+		return if (positive) out else -out
+	}
+
+	inline fun parseDouble(gen: (Int) -> Char): Double {
+		var out = 0.0
+		var frac = 1.0
+		var pointSeen = false
+		var eSeen = false
+		var negate = false
+		var negateExponent = false
+		var exponent = 0
+		var n = 0
+		while (true) {
+			val c = gen(n++)
+			if (c == END) break
+			when (c) {
+				'e', 'E' -> eSeen = true
+				'-' -> {
+					if (eSeen) negateExponent = true else negate = true
+				}
+				'.' -> pointSeen = true
+				else -> {
+					if (eSeen) {
+						exponent *= 10
+						exponent += c.ctypeAsInt()
+					} else {
+						if (pointSeen) frac /= 10
+						out *= 10
+						out += c.ctypeAsInt()
+					}
+				}
+			}
+		}
+		val res = (out * frac) * 10.0.pow(if (negateExponent) -exponent else exponent)
+		return if (negate) -res else res
+	}
+}
+
+@Suppress("ConvertTwoComparisonsToRangeCheck") // @TODO: Kotlin-Native doesn't optimize ranges
+@PublishedApi internal fun Char.ctypeAsInt(): Int = when {
+	this >= '0' && this <= '9' -> this - '0'
+	this >= 'a' && this <= 'z' -> this - 'a' + 10
+	this >= 'A' && this <= 'Z' -> this - 'A' + 10
+	else -> -1
+}

math/src/main/java/com/icegps/math/Alignment.kt

@@ -0,0 +1,47 @@
+package com.icegps.math
+
+import kotlin.math.absoluteValue
+
+////////////////////
+////////////////////
+
+/** Returns the next value of [this] that is multiple of [align]. If [this] is already multiple, returns itself. */
+public fun Int.nextAlignedTo(align: Int): Int = if (this.isAlignedTo(align)) this else (((this / align) + 1) * align)
+/** Returns the next value of [this] that is multiple of [align]. If [this] is already multiple, returns itself. */
+public fun Long.nextAlignedTo(align: Long): Long = if (this.isAlignedTo(align)) this else (((this / align) + 1) * align)
+/** Returns the next value of [this] that is multiple of [align]. If [this] is already multiple, returns itself. */
+public fun Float.nextAlignedTo(align: Float): Float = if (this.isAlignedTo(align)) this else (((this / align).toInt() + 1) * align)
+/** Returns the next value of [this] that is multiple of [align]. If [this] is already multiple, returns itself. */
+public fun Double.nextAlignedTo(align: Double): Double = if (this.isAlignedTo(align)) this else (((this / align).toInt() + 1) * align)
+
+/** Returns the previous value of [this] that is multiple of [align]. If [this] is already multiple, returns itself. */
+public fun Int.prevAlignedTo(align: Int): Int = if (this.isAlignedTo(align)) this else nextAlignedTo(align) - align
+/** Returns the previous value of [this] that is multiple of [align]. If [this] is already multiple, returns itself. */
+public fun Long.prevAlignedTo(align: Long): Long = if (this.isAlignedTo(align)) this else nextAlignedTo(align) - align
+/** Returns the previous value of [this] that is multiple of [align]. If [this] is already multiple, returns itself. */
+public fun Float.prevAlignedTo(align: Float): Float = if (this.isAlignedTo(align)) this else nextAlignedTo(align) - align
+/** Returns the previous value of [this] that is multiple of [align]. If [this] is already multiple, returns itself. */
+public fun Double.prevAlignedTo(align: Double): Double = if (this.isAlignedTo(align)) this else nextAlignedTo(align) - align
+
+/** Returns whether [this] is multiple of [alignment] */
+public fun Int.isAlignedTo(alignment: Int): Boolean = alignment == 0 || (this % alignment) == 0
+/** Returns whether [this] is multiple of [alignment] */
+public fun Long.isAlignedTo(alignment: Long): Boolean = alignment == 0L || (this % alignment) == 0L
+/** Returns whether [this] is multiple of [alignment] */
+public fun Float.isAlignedTo(alignment: Float): Boolean = alignment == 0f || (this % alignment) == 0f
+/** Returns whether [this] is multiple of [alignment] */
+public fun Double.isAlignedTo(alignment: Double): Boolean = alignment == 0.0 || (this % alignment) == 0.0
+
+/** Returns the previous or next value of [this] that is multiple of [align]. If [this] is already multiple, returns itself. */
+public fun Float.nearestAlignedTo(align: Float): Float {
+    val prev = this.prevAlignedTo(align)
+    val next = this.nextAlignedTo(align)
+    return if ((this - prev).absoluteValue < (this - next).absoluteValue) prev else next
+}
+/** Returns the previous or next value of [this] that is multiple of [align]. If [this] is already multiple, returns itself. */
+public fun Double.nearestAlignedTo(align: Double): Double {
+    val prev = this.prevAlignedTo(align)
+    val next = this.nextAlignedTo(align)
+    return if ((this - prev).absoluteValue < (this - next).absoluteValue) prev else next
+}
+