[orx-text-on-contour] Add support for drawing text along contours

orx-text-on-contour/README.md

@@ -0,0 +1,10 @@
+# orx-text-on-contour
+
+Writing texts on contours.
+
+<!-- __demos__ -->
+## Demos
+### DemoTextWriter01
+[source code](src/jvmDemo/kotlin/DemoTextWriter01.kt)
+
+![DemoTextWriter01Kt](https://raw.githubusercontent.com/openrndr/orx/media/orx-text-writer/images/DemoTextWriter01Kt.png)

orx-text-on-contour/build.gradle.kts

@@ -0,0 +1,22 @@
+plugins {
+    org.openrndr.extra.convention.`kotlin-multiplatform`
+}
+
+kotlin {
+    sourceSets {
+        val commonMain by getting {
+            dependencies {
+                implementation(libs.openrndr.shape)
+                implementation(libs.openrndr.draw)
+                implementation(libs.openrndr.application)
+                implementation(project(":orx-shapes"))
+            }
+        }
+
+        val jvmDemo by getting {
+            dependencies {
+                implementation(project(":orx-text-on-contour"))
+            }
+        }
+    }
+}

orx-text-on-contour/src/commonMain/kotlin/TextOnContour.kt

@@ -0,0 +1,271 @@
+package org.openrndr.extra.textoncontour
+
+import org.openrndr.draw.*
+import org.openrndr.extra.shapes.rectify.RectifiedContour
+import org.openrndr.internal.Driver
+import org.openrndr.internal.GlyphRectangle
+import org.openrndr.math.Matrix44
+import org.openrndr.math.Vector2
+import org.openrndr.math.transforms.buildTransform
+import kotlin.math.round
+
+private fun Vector2.transform(m: Matrix44): Vector2 {
+    return (m * this.xy01).xy
+}
+
+private class OnContourImageMapDrawer {
+    var lastPos = Vector2.ZERO
+
+    private val shaderManager: ShadeStyleManager = ShadeStyleManager.fromGenerators(
+        "font-image-map",
+        vsGenerator = Driver.instance.shaderGenerators::fontImageMapVertexShader,
+        fsGenerator = Driver.instance.shaderGenerators::fontImageMapFragmentShader
+    )
+
+    private val maxQuads = 20_000
+
+    private val vertices = VertexBuffer.createDynamic(VertexFormat().apply {
+        textureCoordinate(2)
+        attribute("bounds", VertexElementType.VECTOR4_FLOAT32)
+        position(3)
+        attribute("instance", VertexElementType.FLOAT32)
+    }, 6 * maxQuads)
+
+    private var quadCount = 0
+
+    fun drawTextOnContour(
+        contour: RectifiedContour,
+        context: DrawContext,
+        drawStyle: DrawStyle,
+        text: String,
+        offsetX: Double = 0.0,
+        offsetY: Double = 0.0,
+        tracking: Double = 0.0,
+        scale: Double = 1.0
+    ) = drawTextsOnContours(
+        contour,
+        context,
+        drawStyle,
+        listOf(text),
+        listOf(Vector2(offsetX, offsetY)),
+        tracking,
+        scale
+    )
+
+    class SetResult(val cursorT: List<Double>, val glyphRectangles: List<List<GlyphRectangle>>)
+
+    fun drawTextsOnContours(
+        contour: RectifiedContour,
+        context: DrawContext,
+        drawStyle: DrawStyle,
+        texts: List<String>,
+        positions: List<Vector2>,
+        tracking: Double = 0.0,
+        scale: Double = 1.0
+    ): SetResult {
+        val fontMap = drawStyle.fontMap as? FontImageMap
+        val cursorTs = mutableListOf<Double>()
+
+        if (fontMap != null) {
+            var instance = 0
+
+            val textAndPositionPairs = texts.zip(positions)
+            for ((text, position) in textAndPositionPairs) {
+                var cursorX = position.x
+                val cursorY = 0.0
+
+                val bw = vertices.shadow.writer()
+                bw.position = vertices.vertexFormat.size * quadCount * 6
+
+                var lastChar: Char? = null
+                text.forEach {
+                    val lc = lastChar
+                    if (drawStyle.kerning == KernMode.METRIC) {
+                        cursorX += if (lc != null) fontMap.kerning(lc, it) else 0.0
+                    }
+                    val metrics = fontMap.glyphMetrics[it] ?: fontMap.glyphMetrics.getValue(' ')
+                    val (dx, _) = insertCharacter(
+                        contour,
+                        fontMap,
+                        bw,
+                        it,
+                        cursorX,
+                        position.y + cursorY,
+                        instance,
+                        drawStyle.textSetting,
+                        scale
+                    )
+                    cursorX += metrics.advanceWidth + dx + tracking
+                    lastChar = it
+                }
+                cursorTs.add(cursorX)
+                instance++
+            }
+            flush(context, drawStyle)
+        }
+        return SetResult(cursorTs, emptyList())
+    }
+
+    var queuedInstances = 0
+
+    fun flush(context: DrawContext, drawStyle: DrawStyle) {
+        if (quadCount > 0) {
+            vertices.shadow.uploadElements(0, quadCount * 6)
+            val shader = shaderManager.shader(drawStyle.shadeStyle, vertices.vertexFormat)
+            shader.begin()
+            context.applyToShader(shader)
+
+            Driver.instance.setState(drawStyle)
+            drawStyle.applyToShader(shader)
+            (drawStyle.fontMap as FontImageMap).texture.bind(0)
+            Driver.instance.drawVertexBuffer(
+                shader,
+                listOf(vertices),
+                DrawPrimitive.TRIANGLES,
+                0,
+                quadCount * 6,
+                verticesPerPatch = 0
+            )
+            shader.end()
+            quadCount = 0
+        }
+        queuedInstances = 0
+    }
+
+    private fun insertCharacter(
+        contour: RectifiedContour,
+        fontMap: FontImageMap,
+        bw: BufferWriter,
+        character: Char,
+        cx: Double,
+        cy: Double,
+        instance: Int,
+        textSetting: TextSettingMode,
+        scale: Double
+    ): Pair<Double, GlyphRectangle?> {
+
+        val rectangle = fontMap.map[character] ?: fontMap.map[' ']
+        val targetContentScale = RenderTarget.active.contentScale
+
+        val x = if (textSetting == TextSettingMode.PIXEL) round(cx * targetContentScale) / targetContentScale else cx
+
+        val metrics =
+            fontMap.glyphMetrics[character] ?: fontMap.glyphMetrics[' '] ?: error("glyph or space substitute not found")
+
+        val glyphRectangle =
+            if (rectangle != null) {
+                val pad = 2.0f
+                val ushift = 0.0f
+                val xshift = (metrics.xBitmapShift / fontMap.contentScale).toFloat()
+                val yshift = (metrics.yBitmapShift / fontMap.contentScale).toFloat()
+
+                val u0 = (rectangle.x.toFloat() - pad) / fontMap.texture.effectiveWidth + ushift
+                val u1 =
+                    (rectangle.x.toFloat() + rectangle.width.toFloat() + pad) / fontMap.texture.effectiveWidth + ushift
+                val v0 = (rectangle.y.toFloat() - pad) / fontMap.texture.effectiveHeight
+                val v1 = v0 + (pad * 2 + rectangle.height.toFloat()) / fontMap.texture.effectiveHeight
+
+
+                val x0 = -pad / fontMap.contentScale.toFloat() + xshift
+                val x1 =
+                    (rectangle.width.toFloat() / fontMap.contentScale.toFloat()) + pad / fontMap.contentScale.toFloat() + xshift
+
+
+                val t = (x + (x0 + x1) / 2.0) / (contour.contour.length / scale)
+
+                if (t >= 1.0) {
+                    null
+                } else {
+                    val pose = contour.pose(t)
+
+                    val y0 = -pad / fontMap.contentScale.toFloat() + yshift
+                    val y1 =
+                        rectangle.height.toFloat() / fontMap.contentScale.toFloat() + pad / fontMap.contentScale.toFloat() + yshift
+
+                    val transform = buildTransform {
+                        multiply(
+                            Matrix44(
+                                pose.c0r0, pose.c1r0, pose.c2r0, pose.c3r0 / scale,
+                                pose.c0r1, pose.c1r1, pose.c2r1, pose.c3r1 / scale,
+                                pose.c0r2, pose.c1r2, pose.c2r2, pose.c3r2 / scale,
+                                pose.c0r3, pose.c1r3, pose.c2r3, pose.c3r3,
+                            )
+                        )
+                        multiply(
+                            Matrix44(
+                                -1.0, 0.0, 0.0, 0.0,
+                                0.0, -1.0, 0.0, 0.0,
+                                0.0, 0.0, 1.0, 0.0,
+                                0.0, 0.0, 0.0, 1.0
+                            )
+                        )
+                        translate(-(x0 + x1) / 2.0, 0.0)
+                    }
+
+                    val p00 = Vector2(x0.toDouble(), y0.toDouble())
+                    val p01 = Vector2(x0.toDouble(), y1.toDouble())
+                    val p10 = Vector2(x1.toDouble(), y0.toDouble())
+                    val p11 = Vector2(x1.toDouble(), y1.toDouble())
+
+                    val t00 = p00.transform(transform)
+                    val t01 = p01.transform(transform)
+                    val t10 = p10.transform(transform)
+                    val t11 = p11.transform(transform)
+
+                    lastPos = t00
+
+                    val s0 = 0.0f
+                    val t0 = 0.0f
+                    val s1 = 1.0f
+                    val t1 = 1.0f
+
+                    val w = (x1 - x0)
+                    val h = (y1 - y0)
+                    val z = quadCount.toFloat()
+
+                    val floatInstance = instance.toFloat()
+
+                    if (quadCount < maxQuads) {
+                        bw.apply {
+                            write(u0, v0); write(s0, t0, w, h); write(t00.x.toFloat(), t00.y.toFloat(), z); write(
+                            floatInstance
+                        )
+                            write(u1, v0); write(s1, t0, w, h); write(t10.x.toFloat(), t10.y.toFloat(), z); write(
+                            floatInstance
+                        )
+                            write(u1, v1); write(s1, t1, w, h); write(t11.x.toFloat(), t11.y.toFloat(), z); write(
+                            floatInstance
+                        )
+                            write(u0, v0); write(s0, t0, w, h); write(t00.x.toFloat(), t00.y.toFloat(), z); write(
+                            floatInstance
+                        )
+                            write(u0, v1); write(s0, t1, w, h); write(t01.x.toFloat(), t01.y.toFloat(), z); write(
+                            floatInstance
+                        )
+                            write(u1, v1); write(s1, t1, w, h); write(t11.x.toFloat(), t11.y.toFloat(), z); write(
+                            floatInstance
+                        )
+                        }
+                        quadCount++
+                    }
+                    GlyphRectangle(character, x0.toDouble(), y0.toDouble(), (x1 - x0).toDouble(), (y1 - y0).toDouble())
+                }
+            } else {
+                null
+            }
+        return Pair(x - cx, glyphRectangle)
+    }
+}
+
+private val onContourImageMapDrawer by lazy { OnContourImageMapDrawer() }
+
+/**
+ * Draws a given text along the given contour
+ *
+ * @param text The string to be rendered along the contour.
+ * @param contour The rectified contour along which the text will be rendered.
+ * @param offsetX Optional horizontal offset to shift the starting point of the text along the contour. Default value is 0.0.
+ */
+fun Drawer.textOnContour(text: String, contour: RectifiedContour, offsetX: Double = 0.0) {
+    onContourImageMapDrawer.drawTextOnContour(contour, context, drawStyle, text, offsetX)
+}

orx-text-on-contour/src/jvmDemo/kotlin/DemoTextOnContour01.kt

@@ -0,0 +1,27 @@
+import org.openrndr.application
+import org.openrndr.draw.loadFont
+import org.openrndr.extra.shapes.rectify.rectified
+import org.openrndr.extra.textoncontour.textOnContour
+import org.openrndr.shape.Circle
+
+/**
+ * Demo Functionality includes:
+ * - Loading and applying a specific font (`IBMPlexMono-Regular`) with a size of 32.0.
+ * - Creating a circular contour at the center of the screen with a radius of 200.0.
+ * - Rendering text along the rectified circle's contour.
+ * - Offsetting text positions, enabling repeated text rendering along the same contour.
+ */
+fun main() = application {
+    configure {
+        width = 720
+        height = 720
+    }
+    program {
+        extend {
+            drawer.fontMap = loadFont("demo-data/fonts/IBMPlexMono-Regular.ttf", 32.0)
+            val c = Circle(drawer.bounds.center, 200.0).contour.rectified()
+            drawer.textOnContour("The wheels of the bus go round and round.", c)
+            drawer.textOnContour("The wheels of the bus go round and round.", c, c.contour.length / 2.0)
+        }
+    }
+}

orx-text-writer/src/jvmDemo/kotlin/DemoTextWriter01.kt

@@ -23,20 +23,24 @@ import org.openrndr.shape.Rectangle
  * - `drawer` enables isolated operations for drawing elements.
  * - `writer` facilitates text rendering with alignment and spacing adjustments.
  */
-fun main() = application {
-    program {
-        extend {
-            val r = Rectangle.fromCenter(drawer.bounds.center, 200.0, 200.0)
-            drawer.isolated {
-                drawer.fill = null
-                drawer.stroke = ColorRGBa.WHITE
-                drawer.rectangle(r)
-            }
-            drawer.fontMap = loadFont("demo-data/fonts/IBMPlexMono-Regular.ttf", 24.0)
-            writer {
-                box = r.offsetEdges(-10.0)
-                newLine()
-                text("hello world")
+fun main() {
+
+    application {
+
+        program {
+            extend {
+                val r = Rectangle.fromCenter(drawer.bounds.center, 200.0, 200.0)
+                drawer.isolated {
+                    drawer.fill = null
+                    drawer.stroke = ColorRGBa.WHITE
+                    drawer.rectangle(r)
+                }
+                drawer.fontMap = loadFont("demo-data/fonts/IBMPlexMono-Regular.ttf", 24.0)
+                writer {
+                    box = r.offsetEdges(-10.0)
+                    newLine()
+                    text("hello world")
+                }
             }
         }
     }

settings.gradle.kts

@@ -87,6 +87,7 @@ include(
         "orx-depth-camera",
         "orx-jvm:orx-depth-camera-calibrator",
         "orx-view-box",
+        "orx-text-on-contour",
         "orx-text-writer",
         "orx-turtle"
     )