[orx-panel] Add WatchObjectDiv

orx-panel/src/main/kotlin/org/openrndr/panel/elements/WatchObjectDiv.kt

@@ -0,0 +1,77 @@
+package org.openrndr.panel.elements
+
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.yield
+import org.openrndr.draw.Drawer
+import org.openrndr.launch
+import org.openrndr.panel.elements.*
+import org.openrndr.panel.hash.watchHash
+import kotlin.reflect.KMutableProperty0
+
+class WatchObjectDiv<T:Any>(
+    val watchObject: T,
+    private val builder: WatchObjectDiv<T>.(T) -> Unit
+) : Div(),
+    DisposableElement {
+    override var disposed: Boolean = false
+    private var objectStateHash = watchHash(watchObject)
+    private var watchJob: Job? = null
+
+
+    override fun dispose() {
+        super.dispose()
+        for (child in children) {
+            child.parent = null
+            (child as? DisposableElement)?.dispose()
+        }
+        children.clear()
+    }
+
+    fun regenerate(force: Boolean = false) {
+        var regenerate = force
+        if (watchHash(watchObject) != objectStateHash) {
+            regenerate = true
+        }
+
+        if (regenerate) {
+            for (child in children) {
+                child.parent = null
+                (child as? DisposableElement)?.dispose()
+            }
+            objectStateHash = watchHash(watchObject)
+            children.clear()
+            builder(watchObject)
+
+            requestRedraw()
+        }
+    }
+
+    fun checkJob() {
+        if (watchJob == null) {
+            watchJob = (root() as? Body)?.controlManager?.program?.launch {
+                while (!disposed) {
+                    regenerate()
+                    yield()
+                }
+            }
+        }
+    }
+
+    override fun draw(drawer: Drawer) {
+        checkJob()
+        super.draw(drawer)
+    }
+}
+
+fun <T : Any> Element.watchObjectDiv(
+    vararg classes: String,
+    watchObject: T,
+    builder: WatchObjectDiv<T>.(T) -> Unit
+) : WatchObjectDiv<T> {
+    val wd = WatchObjectDiv(watchObject, builder)
+    wd.classes.addAll(classes.map { ElementClass(it) })
+    this.append(wd)
+    wd.regenerate(true)
+    wd.checkJob()
+    return wd
+}

orx-panel/src/main/kotlin/org/openrndr/panel/hash/WatchHash.kt

@@ -0,0 +1,19 @@
+package org.openrndr.panel.hash
+
+import kotlin.reflect.KProperty0
+import kotlin.reflect.full.declaredMemberProperties
+
+fun watchHash(toHash: Any): Int {
+    var hash = 0
+    for (property in toHash::class.declaredMemberProperties) {
+        val v = (property.getter)(toHash)
+        if (v is KProperty0<*>) {
+            val pv = v.get()
+            hash = 31 * hash + (pv?.hashCode() ?: 0)
+        } else {
+            hash = 31 * hash + (v?.hashCode() ?: 0)
+        }
+    }
+    return hash
+}
+