Use onPlaced for screenshot tests (#433)

This fixes misplaced/drawing issues in screenshot tests (Roborazzi, etc) due to our usage of `onGloballyPositioned`. `onGloballyPositioned` will be called after an entire composition, therefore doesn't work for screenshot tests which only 'run' the content until the first draw. In this instance, we use now `onPlaced` to prime the various internal state.
chrisbanes · Dec 4, 2024 · 9c639ff · 9c639ff
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diff --git a/haze/api/api.txt b/haze/api/api.txt
@@ -9,7 +9,7 @@ package dev.chrisbanes.haze {
     method @androidx.compose.runtime.Stable public static androidx.compose.ui.Modifier hazeChild(androidx.compose.ui.Modifier, dev.chrisbanes.haze.HazeState state, optional dev.chrisbanes.haze.HazeStyle style, optional kotlin.jvm.functions.Function1<? super dev.chrisbanes.haze.HazeChildScope,kotlin.Unit>? block);
   }
 
-  @dev.chrisbanes.haze.ExperimentalHazeApi public final class HazeChildNode extends androidx.compose.ui.Modifier.Node implements androidx.compose.ui.node.CompositionLocalConsumerModifierNode androidx.compose.ui.node.DrawModifierNode androidx.compose.ui.node.GlobalPositionAwareModifierNode dev.chrisbanes.haze.HazeChildScope androidx.compose.ui.node.ObserverModifierNode {
+  @dev.chrisbanes.haze.ExperimentalHazeApi public final class HazeChildNode extends androidx.compose.ui.Modifier.Node implements androidx.compose.ui.node.CompositionLocalConsumerModifierNode androidx.compose.ui.node.DrawModifierNode androidx.compose.ui.node.GlobalPositionAwareModifierNode dev.chrisbanes.haze.HazeChildScope androidx.compose.ui.node.LayoutAwareModifierNode androidx.compose.ui.node.ObserverModifierNode {
     ctor public HazeChildNode(dev.chrisbanes.haze.HazeState state, optional dev.chrisbanes.haze.HazeStyle style, optional kotlin.jvm.functions.Function1<? super dev.chrisbanes.haze.HazeChildScope,kotlin.Unit>? block);
     method public void draw(androidx.compose.ui.graphics.drawscope.ContentDrawScope);
     method public float getAlpha();
@@ -132,7 +132,7 @@ package dev.chrisbanes.haze {
     method @androidx.compose.runtime.Stable public static androidx.compose.ui.Modifier haze(androidx.compose.ui.Modifier, dev.chrisbanes.haze.HazeState state);
   }
 
-  @dev.chrisbanes.haze.ExperimentalHazeApi public final class HazeNode extends androidx.compose.ui.Modifier.Node implements androidx.compose.ui.node.CompositionLocalConsumerModifierNode androidx.compose.ui.node.DrawModifierNode androidx.compose.ui.node.GlobalPositionAwareModifierNode {
+  @dev.chrisbanes.haze.ExperimentalHazeApi public final class HazeNode extends androidx.compose.ui.Modifier.Node implements androidx.compose.ui.node.CompositionLocalConsumerModifierNode androidx.compose.ui.node.DrawModifierNode androidx.compose.ui.node.GlobalPositionAwareModifierNode androidx.compose.ui.node.LayoutAwareModifierNode {
     ctor public HazeNode(dev.chrisbanes.haze.HazeState state);
     method public void draw(androidx.compose.ui.graphics.drawscope.ContentDrawScope);
     method public dev.chrisbanes.haze.HazeState getState();

diff --git a/haze/src/commonMain/kotlin/dev/chrisbanes/haze/HazeChildNode.kt b/haze/src/commonMain/kotlin/dev/chrisbanes/haze/HazeChildNode.kt
@@ -9,6 +9,7 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.geometry.Offset
 import androidx.compose.ui.geometry.Size
 import androidx.compose.ui.geometry.isSpecified
+import androidx.compose.ui.geometry.isUnspecified
 import androidx.compose.ui.geometry.takeOrElse
 import androidx.compose.ui.geometry.toRect
 import androidx.compose.ui.graphics.Brush
@@ -30,6 +31,7 @@ import androidx.compose.ui.layout.positionInWindow
 import androidx.compose.ui.node.CompositionLocalConsumerModifierNode
 import androidx.compose.ui.node.DrawModifierNode
 import androidx.compose.ui.node.GlobalPositionAwareModifierNode
+import androidx.compose.ui.node.LayoutAwareModifierNode
 import androidx.compose.ui.node.ObserverModifierNode
 import androidx.compose.ui.node.currentValueOf
 import androidx.compose.ui.node.invalidateDraw
@@ -58,6 +60,7 @@ class HazeChildNode(
 ) : Modifier.Node(),
   CompositionLocalConsumerModifierNode,
   GlobalPositionAwareModifierNode,
+  LayoutAwareModifierNode,
   ObserverModifierNode,
   DrawModifierNode,
   HazeChildScope {
@@ -240,12 +243,23 @@ class HazeChildNode(
     }
   }
 
-  override fun onGloballyPositioned(coordinates: LayoutCoordinates) {
-    log(TAG) {
-      "onGloballyPositioned: " +
-        "positionInWindow=${coordinates.positionInWindow()}"
+  override fun onPlaced(coordinates: LayoutCoordinates) {
+    // If the positionOnScreen has not been placed yet, we use the value from onPlaced,
+    // otherwise we ignore it. This primarily fixes screenshot tests which only run tests
+    // up to the first draw. We usually need onGloballyPositioned which tends to happen after
+    // the first pass
+    if (positionInContent.isUnspecified) {
+      log(TAG) { "onPlaced: positionInWindow=${coordinates.positionInWindow()}" }
+      onPositioned(coordinates)
     }
+  }
+
+  override fun onGloballyPositioned(coordinates: LayoutCoordinates) {
+    log(TAG) { "onGloballyPositioned: positionInWindow=${coordinates.positionInWindow()}" }
+    onPositioned(coordinates)
+  }
 
+  private fun onPositioned(coordinates: LayoutCoordinates) {
     positionInContent = coordinates.positionInWindow() +
       calculateWindowOffset() - state.positionOnScreen.takeOrElse { Offset.Zero }
 

diff --git a/haze/src/commonMain/kotlin/dev/chrisbanes/haze/HazeNode.kt b/haze/src/commonMain/kotlin/dev/chrisbanes/haze/HazeNode.kt
@@ -3,7 +3,9 @@
 
 package dev.chrisbanes.haze
 
+import androidx.compose.runtime.snapshots.Snapshot
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.geometry.isUnspecified
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.drawscope.ContentDrawScope
 import androidx.compose.ui.graphics.drawscope.DrawScope
@@ -13,6 +15,7 @@ import androidx.compose.ui.layout.positionInWindow
 import androidx.compose.ui.node.CompositionLocalConsumerModifierNode
 import androidx.compose.ui.node.DrawModifierNode
 import androidx.compose.ui.node.GlobalPositionAwareModifierNode
+import androidx.compose.ui.node.LayoutAwareModifierNode
 import androidx.compose.ui.node.currentValueOf
 import androidx.compose.ui.platform.LocalGraphicsContext
 import androidx.compose.ui.unit.Dp
@@ -33,15 +36,36 @@ class HazeNode(
 ) : Modifier.Node(),
   CompositionLocalConsumerModifierNode,
   GlobalPositionAwareModifierNode,
+  LayoutAwareModifierNode,
   DrawModifierNode {
 
+  override fun onPlaced(coordinates: LayoutCoordinates) {
+    // If the positionOnScreen has not been placed yet, we use the value on onPlaced,
+    // otherwise we ignore it. This primarily fixes screenshot tests which only run tests
+    // up to the first draw. We need onGloballyPositioned which tends to happen after
+    // the first pass
+    Snapshot.withoutReadObservation {
+      if (state.positionOnScreen.isUnspecified) {
+        log(TAG) {
+          "onPlaced: " +
+            "positionInWindow=${coordinates.positionInWindow()}, " +
+            "content positionOnScreens=${state.positionOnScreen}"
+        }
+        onPositioned(coordinates)
+      }
+    }
+  }
+
   override fun onGloballyPositioned(coordinates: LayoutCoordinates) {
     log(TAG) {
       "onGloballyPositioned: " +
         "positionInWindow=${coordinates.positionInWindow()}, " +
         "content positionOnScreens=${state.positionOnScreen}"
     }
+    onPositioned(coordinates)
+  }
 
+  private fun onPositioned(coordinates: LayoutCoordinates) {
     state.positionOnScreen = coordinates.positionInWindow() + calculateWindowOffset()
   }