Merge "Do not draw elements that are not part of the transition" into main (343ffe51) · Commits · e / os / android_frameworks_base

packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/Element.kt

+13 −10

Original line number	Diff line number	Diff line
		@@ -261,16 +261,19 @@ private fun shouldDrawElement(
		scene: Scene,
		element: Element,
		): Boolean {
		val transition = layoutImpl.state.currentTransition

		// Always draw the element if there is no ongoing transition or if the element is not shared or
		// if the current scene is the one that is currently over scrolling with [OverscrollSpec].
		if (
		transition == null \|\|
		transition.fromScene !in element.sceneStates \|\|
		transition.toScene !in element.sceneStates \|\|
		transition.currentOverscrollSpec?.scene == scene.key
		) {
		val transition = layoutImpl.state.currentTransition ?: return true

		val inFromScene = transition.fromScene in element.sceneStates
		val inToScene = transition.toScene in element.sceneStates

		// If an element is not present in any scene, it should not be drawn.
		if (!inFromScene && !inToScene) {
		return false
		}

		// Always draw if the element is not shared or if the current scene is the one that is currently
		// over scrolling with [OverscrollSpec].
		if (!inFromScene \|\| !inToScene \|\| transition.currentOverscrollSpec?.scene == scene.key) {
		return true
		}

packages/SystemUI/compose/scene/tests/src/com/android/compose/animation/scene/ElementTest.kt

+55 −0

Original line number	Diff line number	Diff line
		@@ -45,6 +45,7 @@ import androidx.compose.ui.Modifier
		import androidx.compose.ui.geometry.Offset
		import androidx.compose.ui.layout.intermediateLayout
		import androidx.compose.ui.platform.LocalViewConfiguration
		import androidx.compose.ui.test.assertIsNotDisplayed
		import androidx.compose.ui.test.assertTopPositionInRootIsEqualTo
		import androidx.compose.ui.test.junit4.createComposeRule
		import androidx.compose.ui.test.onNodeWithTag
		@@ -174,6 +175,60 @@ class ElementTest {
		}
		}

		@Test
		fun elementsNotInTransition_shouldNotBeDrawn() {
		val nFrames = 20
		val frameDuration = 16L
		val tween = tween<Float>(nFrames * frameDuration.toInt())
		val layoutSize = 100.dp
		val elementSize = 50.dp
		val elementOffset = 20.dp

		lateinit var changeScene: (SceneKey) -> Unit

		rule.testTransition(
		from = TestScenes.SceneA,
		to = TestScenes.SceneB,
		transitionLayout = { currentScene, onChangeScene ->
		changeScene = onChangeScene

		SceneTransitionLayout(
		currentScene,
		onChangeScene,
		transitions {
		from(TestScenes.SceneA, to = TestScenes.SceneB) { spec = tween }
		from(TestScenes.SceneB, to = TestScenes.SceneC) { spec = tween }
		},
		) {
		scene(TestScenes.SceneA) {
		Box(Modifier.size(layoutSize)) {
		// Transformed element
		Element(
		TestElements.Bar,
		elementSize,
		elementOffset,
		)
		}
		}
		scene(TestScenes.SceneB) { Box(Modifier.size(layoutSize)) }
		scene(TestScenes.SceneC) { Box(Modifier.size(layoutSize)) }
		}
		},
		) {
		// Start transition from SceneA to SceneB
		at(1 * frameDuration) {
		onElement(TestElements.Bar).assertExists()

		// Start transition from SceneB to SceneC
		changeScene(TestScenes.SceneC)
		}

		at(2 * frameDuration) { onElement(TestElements.Bar).assertIsNotDisplayed() }

		at(3 * frameDuration) { onElement(TestElements.Bar).assertDoesNotExist() }
		}
		}

		@Test
		fun onlyMovingElements_noLayout_onlyPlacement() {
		val nFrames = 20