Merge "Animate SceneTransitionLayout size" into main

11 files changed, 117 insertions, 37 deletions

diff --git a/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/Element.kt b/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/Element.kt
index aae61bd0f554..b77a60b5b5d6 100644
--- a/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/Element.kt
+++ b/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/Element.kt
@@ -506,7 +506,10 @@ private inline fun <T> computeValue(
 
     // There is no ongoing transition.
     if (state !is TransitionState.Transition || state.fromScene == state.toScene) {
-        return idleValue
+        // Even if this element SceneTransitionLayout is not animated, the layout itself might be
+        // animated (e.g. by another parent SceneTransitionLayout), in which case this element still
+        // need to participate in the layout phase.
+        return currentValue()
     }
 
     // A transition was started but it's not ready yet (not all elements have been composed/laid
diff --git a/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/GestureHandler.kt b/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/GestureHandler.kt
index 216608aff0cb..5d8eaf7f3d15 100644
--- a/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/GestureHandler.kt
+++ b/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/GestureHandler.kt
@@ -2,9 +2,10 @@ package com.android.compose.animation.scene
 
 import androidx.compose.ui.geometry.Offset
 import androidx.compose.ui.input.nestedscroll.NestedScrollConnection
+import androidx.compose.ui.unit.IntSize
 
 interface DraggableHandler {
-    fun onDragStarted(startedPosition: Offset, pointersDown: Int = 1)
+    fun onDragStarted(layoutSize: IntSize, startedPosition: Offset, pointersDown: Int = 1)
     fun onDelta(pixels: Float)
     fun onDragStopped(velocity: Float)
 }
diff --git a/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/MultiPointerDraggable.kt b/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/MultiPointerDraggable.kt
index d0a5f5bfebc0..d48781a4529b 100644
--- a/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/MultiPointerDraggable.kt
+++ b/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/MultiPointerDraggable.kt
@@ -38,6 +38,7 @@ import androidx.compose.ui.input.pointer.positionChange
 import androidx.compose.ui.input.pointer.util.VelocityTracker
 import androidx.compose.ui.input.pointer.util.addPointerInputChange
 import androidx.compose.ui.platform.LocalViewConfiguration
+import androidx.compose.ui.unit.IntSize
 import androidx.compose.ui.unit.Velocity
 import androidx.compose.ui.util.fastForEach
 
@@ -60,7 +61,7 @@ internal fun Modifier.multiPointerDraggable(
     orientation: Orientation,
     enabled: Boolean,
     startDragImmediately: Boolean,
-    onDragStarted: (startedPosition: Offset, pointersDown: Int) -> Unit,
+    onDragStarted: (layoutSize: IntSize, startedPosition: Offset, pointersDown: Int) -> Unit,
     onDragDelta: (Float) -> Unit,
     onDragStopped: (velocity: Float) -> Unit,
 ): Modifier = composed {
@@ -83,7 +84,7 @@ internal fun Modifier.multiPointerDraggable(
 
         val onDragStart: (Offset, Int) -> Unit = { startedPosition, pointersDown ->
             velocityTracker.resetTracking()
-            onDragStarted(startedPosition, pointersDown)
+            onDragStarted(size, startedPosition, pointersDown)
         }
 
         val onDragCancel: () -> Unit = { onDragStopped(/* velocity= */ 0f) }
diff --git a/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/Scene.kt b/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/Scene.kt
index eb5168bdd3cb..1a79522da05d 100644
--- a/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/Scene.kt
+++ b/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/Scene.kt
@@ -25,8 +25,9 @@ import androidx.compose.runtime.mutableFloatStateOf
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.setValue
 import androidx.compose.runtime.snapshots.SnapshotStateMap
+import androidx.compose.ui.ExperimentalComposeUiApi
 import androidx.compose.ui.Modifier
-import androidx.compose.ui.layout.onPlaced
+import androidx.compose.ui.layout.intermediateLayout
 import androidx.compose.ui.platform.testTag
 import androidx.compose.ui.unit.IntSize
 import androidx.compose.ui.zIndex
@@ -44,14 +45,24 @@ internal class Scene(
     var content by mutableStateOf(content)
     var userActions by mutableStateOf(actions)
     var zIndex by mutableFloatStateOf(zIndex)
-    var size by mutableStateOf(IntSize.Zero)
+    var targetSize by mutableStateOf(IntSize.Zero)
 
     /** The shared values in this scene that are not tied to a specific element. */
     val sharedValues = SnapshotStateMap<ValueKey, Element.SharedValue<*>>()
 
     @Composable
+    @OptIn(ExperimentalComposeUiApi::class)
     fun Content(modifier: Modifier = Modifier) {
-        Box(modifier.zIndex(zIndex).onPlaced { size = it.size }.testTag(key.testTag)) {
+        Box(
+            modifier
+                .zIndex(zIndex)
+                .intermediateLayout { measurable, constraints ->
+                    targetSize = lookaheadSize
+                    val placeable = measurable.measure(constraints)
+                    layout(placeable.width, placeable.height) { placeable.place(0, 0) }
+                }
+                .testTag(key.testTag)
+        ) {
             scope.content()
         }
     }
diff --git a/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/SceneGestureHandler.kt b/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/SceneGestureHandler.kt
index 9a3a0aef30cb..9d71801be25b 100644
--- a/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/SceneGestureHandler.kt
+++ b/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/SceneGestureHandler.kt
@@ -27,6 +27,7 @@ import androidx.compose.runtime.mutableFloatStateOf
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.unit.IntSize
 import androidx.compose.ui.unit.Velocity
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.round
@@ -90,7 +91,7 @@ class SceneGestureHandler(
 
     internal var gestureWithPriority: Any? = null
 
-    internal fun onDragStarted(pointersDown: Int, startedPosition: Offset?) {
+    internal fun onDragStarted(pointersDown: Int, layoutSize: IntSize, startedPosition: Offset?) {
         if (isDrivingTransition) {
             // This [transition] was already driving the animation: simply take over it.
             // Stop animating and start from where the current offset.
@@ -126,14 +127,14 @@ class SceneGestureHandler(
         // we will also have to make sure that we correctly handle overscroll.
         swipeTransition.absoluteDistance =
             when (orientation) {
-                Orientation.Horizontal -> layoutImpl.size.width
-                Orientation.Vertical -> layoutImpl.size.height
+                Orientation.Horizontal -> layoutSize.width
+                Orientation.Vertical -> layoutSize.height
             }.toFloat()
 
         val fromEdge =
             startedPosition?.let { position ->
                 layoutImpl.edgeDetector.edge(
-                    layoutImpl.size,
+                    layoutSize,
                     position.round(),
                     layoutImpl.density,
                     orientation,
@@ -513,9 +514,9 @@ class SceneGestureHandler(
 private class SceneDraggableHandler(
     private val gestureHandler: SceneGestureHandler,
 ) : DraggableHandler {
-    override fun onDragStarted(startedPosition: Offset, pointersDown: Int) {
+    override fun onDragStarted(layoutSize: IntSize, startedPosition: Offset, pointersDown: Int) {
         gestureHandler.gestureWithPriority = this
-        gestureHandler.onDragStarted(pointersDown, startedPosition)
+        gestureHandler.onDragStarted(pointersDown, layoutSize, startedPosition)
     }
 
     override fun onDelta(pixels: Float) {
@@ -647,7 +648,11 @@ class SceneNestedScrollHandler(
             canContinueScroll = { true },
             onStart = {
                 gestureHandler.gestureWithPriority = this
-                gestureHandler.onDragStarted(pointersDown = 1, startedPosition = null)
+                gestureHandler.onDragStarted(
+                    pointersDown = 1,
+                    layoutSize = gestureHandler.currentScene.targetSize,
+                    startedPosition = null,
+                )
             },
             onScroll = { offsetAvailable ->
                 if (gestureHandler.gestureWithPriority != this) {
diff --git a/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/SceneTransitionLayoutImpl.kt b/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/SceneTransitionLayoutImpl.kt
index 6edd1b6b923d..0b06953bc8e2 100644
--- a/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/SceneTransitionLayoutImpl.kt
+++ b/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/SceneTransitionLayoutImpl.kt
@@ -30,13 +30,15 @@ import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
 import androidx.compose.runtime.snapshots.SnapshotStateMap
+import androidx.compose.ui.ExperimentalComposeUiApi
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.drawWithContent
 import androidx.compose.ui.layout.LookaheadScope
-import androidx.compose.ui.layout.onSizeChanged
+import androidx.compose.ui.layout.intermediateLayout
 import androidx.compose.ui.unit.Density
 import androidx.compose.ui.unit.IntSize
 import androidx.compose.ui.util.fastForEach
+import com.android.compose.ui.util.lerp
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.channels.Channel
 
@@ -64,12 +66,6 @@ class SceneTransitionLayoutImpl(
     private val horizontalGestureHandler: SceneGestureHandler
     private val verticalGestureHandler: SceneGestureHandler
 
-    /**
-     * The size of this layout. Note that this could be [IntSize.Zero] if this layour does not have
-     * any scene configured or right before the first measure pass of the layout.
-     */
-    @VisibleForTesting var size by mutableStateOf(IntSize.Zero)
-
     init {
         setScenes(builder)
 
@@ -157,15 +153,46 @@ class SceneTransitionLayoutImpl(
     }
 
     @Composable
+    @OptIn(ExperimentalComposeUiApi::class)
     internal fun Content(modifier: Modifier) {
         Box(
             modifier
                 // Handle horizontal and vertical swipes on this layout.
                 // Note: order here is important and will give a slight priority to the vertical
                 // swipes.
-                .swipeToScene(gestureHandler(Orientation.Horizontal))
-                .swipeToScene(gestureHandler(Orientation.Vertical))
-                .onSizeChanged { size = it }
+                .swipeToScene(horizontalGestureHandler)
+                .swipeToScene(verticalGestureHandler)
+                // Animate the size of this layout.
+                .intermediateLayout { measurable, constraints ->
+                    // Measure content normally.
+                    val placeable = measurable.measure(constraints)
+
+                    val width: Int
+                    val height: Int
+                    val state = state.transitionState
+                    if (state !is TransitionState.Transition || state.fromScene == state.toScene) {
+                        width = placeable.width
+                        height = placeable.height
+                    } else {
+                        // Interpolate the size.
+                        val fromSize = scene(state.fromScene).targetSize
+                        val toSize = scene(state.toScene).targetSize
+
+                        // Optimization: make sure we don't read state.progress if fromSize ==
+                        // toSize to avoid running this code every frame when the layout size does
+                        // not change.
+                        if (fromSize == toSize) {
+                            width = fromSize.width
+                            height = fromSize.height
+                        } else {
+                            val size = lerp(fromSize, toSize, state.progress)
+                            width = size.width.coerceAtLeast(0)
+                            height = size.height.coerceAtLeast(0)
+                        }
+                    }
+
+                    layout(width, height) { placeable.place(0, 0) }
+                }
         ) {
             LookaheadScope {
                 val scenesToCompose =
@@ -230,4 +257,9 @@ class SceneTransitionLayoutImpl(
     }
 
     internal fun isSceneReady(scene: SceneKey): Boolean = readyScenes.containsKey(scene)
+
+    @VisibleForTesting
+    fun setScenesTargetSizeForTest(size: IntSize) {
+        scenes.values.forEach { it.targetSize = size }
+    }
 }
diff --git a/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/transformation/EdgeTranslate.kt b/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/transformation/EdgeTranslate.kt
index 840800d838db..70534dde4f6f 100644
--- a/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/transformation/EdgeTranslate.kt
+++ b/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/transformation/EdgeTranslate.kt
@@ -38,7 +38,7 @@ internal class EdgeTranslate(
         transition: TransitionState.Transition,
         value: Offset
     ): Offset {
-        val sceneSize = scene.size
+        val sceneSize = scene.targetSize
         val elementSize = sceneValues.targetSize
         if (elementSize == Element.SizeUnspecified) {
             return value
diff --git a/packages/SystemUI/compose/scene/tests/src/com/android/compose/animation/scene/SceneGestureHandlerTest.kt b/packages/SystemUI/compose/scene/tests/src/com/android/compose/animation/scene/SceneGestureHandlerTest.kt
index 1e3d01108103..7ab2096b3d88 100644
--- a/packages/SystemUI/compose/scene/tests/src/com/android/compose/animation/scene/SceneGestureHandlerTest.kt
+++ b/packages/SystemUI/compose/scene/tests/src/com/android/compose/animation/scene/SceneGestureHandlerTest.kt
@@ -46,6 +46,7 @@ import org.junit.Test
 import org.junit.runner.RunWith
 
 private const val SCREEN_SIZE = 100f
+private val LAYOUT_SIZE = IntSize(SCREEN_SIZE.toInt(), SCREEN_SIZE.toInt())
 
 @RunWith(AndroidJUnit4::class)
 class SceneGestureHandlerTest {
@@ -80,7 +81,7 @@ class SceneGestureHandlerTest {
                             edgeDetector = DefaultEdgeDetector,
                             coroutineScope = coroutineScope,
                         )
-                        .also { it.size = IntSize(SCREEN_SIZE.toInt(), SCREEN_SIZE.toInt()) },
+                        .apply { setScenesTargetSizeForTest(LAYOUT_SIZE) },
                 orientation = Orientation.Vertical,
                 coroutineScope = coroutineScope,
             )
@@ -128,18 +129,21 @@ class SceneGestureHandlerTest {
         runMonotonicClockTest { TestGestureScope(coroutineScope = this).block() }
     }
 
+    private fun DraggableHandler.onDragStarted() =
+        onDragStarted(layoutSize = LAYOUT_SIZE, startedPosition = Offset.Zero)
+
     @Test
     fun testPreconditions() = runGestureTest { assertScene(currentScene = SceneA, isIdle = true) }
 
     @Test
     fun onDragStarted_shouldStartATransition() = runGestureTest {
-        draggable.onDragStarted(startedPosition = Offset.Zero)
+        draggable.onDragStarted()
         assertScene(currentScene = SceneA, isIdle = false)
     }
 
     @Test
     fun afterSceneTransitionIsStarted_interceptDragEvents() = runGestureTest {
-        draggable.onDragStarted(startedPosition = Offset.Zero)
+        draggable.onDragStarted()
         assertScene(currentScene = SceneA, isIdle = false)
         val transition = transitionState as Transition
 
@@ -152,7 +156,7 @@ class SceneGestureHandlerTest {
 
     @Test
     fun onDragStoppedAfterDrag_velocityLowerThanThreshold_remainSameScene() = runGestureTest {
-        draggable.onDragStarted(startedPosition = Offset.Zero)
+        draggable.onDragStarted()
         assertScene(currentScene = SceneA, isIdle = false)
 
         draggable.onDelta(pixels = deltaInPixels10)
@@ -170,7 +174,7 @@ class SceneGestureHandlerTest {
 
     @Test
     fun onDragStoppedAfterDrag_velocityAtLeastThreshold_goToNextScene() = runGestureTest {
-        draggable.onDragStarted(startedPosition = Offset.Zero)
+        draggable.onDragStarted()
         assertScene(currentScene = SceneA, isIdle = false)
 
         draggable.onDelta(pixels = deltaInPixels10)
@@ -188,7 +192,7 @@ class SceneGestureHandlerTest {
 
     @Test
     fun onDragStoppedAfterStarted_returnImmediatelyToIdle() = runGestureTest {
-        draggable.onDragStarted(startedPosition = Offset.Zero)
+        draggable.onDragStarted()
         assertScene(currentScene = SceneA, isIdle = false)
 
         draggable.onDragStopped(velocity = 0f)
@@ -197,7 +201,7 @@ class SceneGestureHandlerTest {
 
     @Test
     fun startGestureDuringAnimatingOffset_shouldImmediatelyStopTheAnimation() = runGestureTest {
-        draggable.onDragStarted(startedPosition = Offset.Zero)
+        draggable.onDragStarted()
         assertScene(currentScene = SceneA, isIdle = false)
 
         draggable.onDelta(pixels = deltaInPixels10)
@@ -217,7 +221,7 @@ class SceneGestureHandlerTest {
         assertScene(currentScene = SceneC, isIdle = false)
 
         // Start a new gesture while the offset is animating
-        draggable.onDragStarted(startedPosition = Offset.Zero)
+        draggable.onDragStarted()
         assertThat(sceneGestureHandler.isAnimatingOffset).isFalse()
     }
 
@@ -421,6 +425,7 @@ class SceneGestureHandlerTest {
         draggable.onDelta(deltaInPixels10)
         assertScene(currentScene = SceneA, isIdle = true)
     }
+
     @Test
     fun beforeDraggableStart_stop_shouldBeIgnored() = runGestureTest {
         draggable.onDragStopped(velocityThreshold)
@@ -437,7 +442,7 @@ class SceneGestureHandlerTest {
     @Test
     fun startNestedScrollWhileDragging() = runGestureTest {
         val nestedScroll = nestedScrollConnection(nestedScrollBehavior = Always)
-        draggable.onDragStarted(Offset.Zero)
+        draggable.onDragStarted()
         assertScene(currentScene = SceneA, isIdle = false)
         val transition = transitionState as Transition
 
diff --git a/packages/SystemUI/compose/scene/tests/src/com/android/compose/animation/scene/SceneTransitionLayoutTest.kt b/packages/SystemUI/compose/scene/tests/src/com/android/compose/animation/scene/SceneTransitionLayoutTest.kt
index 5afd420a5e16..321cf637824a 100644
--- a/packages/SystemUI/compose/scene/tests/src/com/android/compose/animation/scene/SceneTransitionLayoutTest.kt
+++ b/packages/SystemUI/compose/scene/tests/src/com/android/compose/animation/scene/SceneTransitionLayoutTest.kt
@@ -18,6 +18,8 @@ package com.android.compose.animation.scene
 
 import androidx.activity.ComponentActivity
 import androidx.compose.animation.core.FastOutSlowInEasing
+import androidx.compose.animation.core.LinearEasing
+import androidx.compose.animation.core.tween
 import androidx.compose.foundation.background
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.fillMaxSize
@@ -48,6 +50,7 @@ import androidx.compose.ui.unit.DpOffset
 import androidx.compose.ui.unit.IntOffset
 import androidx.compose.ui.unit.dp
 import androidx.test.ext.junit.runners.AndroidJUnit4
+import com.android.compose.test.assertSizeIsEqualTo
 import com.android.compose.test.subjects.DpOffsetSubject
 import com.android.compose.test.subjects.assertThat
 import com.google.common.truth.Truth.assertThat
@@ -307,6 +310,26 @@ class SceneTransitionLayoutTest {
         assertThat(layoutState.transitionState.currentScene).isEqualTo(TestScenes.SceneA)
     }
 
+    @Test
+    fun layoutSizeIsAnimated() {
+        val layoutTag = "layout"
+        rule.testTransition(
+            fromSceneContent = { Box(Modifier.size(200.dp, 100.dp)) },
+            toSceneContent = { Box(Modifier.size(120.dp, 140.dp)) },
+            transition = {
+                // 4 frames of animation.
+                spec = tween(4 * 16, easing = LinearEasing)
+            },
+            layoutModifier = Modifier.testTag(layoutTag),
+        ) {
+            before { rule.onNodeWithTag(layoutTag).assertSizeIsEqualTo(200.dp, 100.dp) }
+            at(16) { rule.onNodeWithTag(layoutTag).assertSizeIsEqualTo(180.dp, 110.dp) }
+            at(32) { rule.onNodeWithTag(layoutTag).assertSizeIsEqualTo(160.dp, 120.dp) }
+            at(48) { rule.onNodeWithTag(layoutTag).assertSizeIsEqualTo(140.dp, 130.dp) }
+            after { rule.onNodeWithTag(layoutTag).assertSizeIsEqualTo(120.dp, 140.dp) }
+        }
+    }
+
     private fun SemanticsNodeInteraction.offsetRelativeTo(
         other: SemanticsNodeInteraction,
     ): DpOffset {
diff --git a/packages/SystemUI/compose/scene/tests/src/com/android/compose/animation/scene/transformation/EdgeTranslateTest.kt b/packages/SystemUI/compose/scene/tests/src/com/android/compose/animation/scene/transformation/EdgeTranslateTest.kt
index 2a27763f1d5c..8cffcf6980cc 100644
--- a/packages/SystemUI/compose/scene/tests/src/com/android/compose/animation/scene/transformation/EdgeTranslateTest.kt
+++ b/packages/SystemUI/compose/scene/tests/src/com/android/compose/animation/scene/transformation/EdgeTranslateTest.kt
@@ -48,7 +48,7 @@ class EdgeTranslateTest {
         rule.testTransition(
             // The layout under test is 300dp x 300dp.
             layoutModifier = Modifier.size(300.dp),
-            fromSceneContent = {},
+            fromSceneContent = { Box(Modifier.fillMaxSize()) },
             toSceneContent = {
                 // Foo is 100dp x 100dp in the center of the layout, so at offset = (100dp, 100dp)
                 Box(Modifier.fillMaxSize()) {
diff --git a/packages/SystemUI/compose/scene/tests/utils/src/com/android/compose/animation/scene/TestTransition.kt b/packages/SystemUI/compose/scene/tests/utils/src/com/android/compose/animation/scene/TestTransition.kt
index e0ae1be69aaf..06de2965f716 100644
--- a/packages/SystemUI/compose/scene/tests/utils/src/com/android/compose/animation/scene/TestTransition.kt
+++ b/packages/SystemUI/compose/scene/tests/utils/src/com/android/compose/animation/scene/TestTransition.kt
@@ -16,7 +16,6 @@
 
 package com.android.compose.animation.scene
 
-import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
@@ -104,7 +103,7 @@ fun ComposeContentTestRule.testTransition(
                 currentScene,
                 onChangeScene,
                 transitions { from(fromScene, to = toScene, transition) },
-                layoutModifier.fillMaxSize(),
+                layoutModifier,
             ) {
                 scene(fromScene, content = fromSceneContent)
                 scene(toScene, content = toSceneContent)