STL ElementStateScope exposes lastSize() (1faa0111) · Commits · e / os / android_frameworks_base

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

+5 −2

Original line number	Diff line number	Diff line
		@@ -107,7 +107,7 @@ internal class Element(val key: ElementKey) {

		/** The last state this element had in this content. */
		var lastOffset = Offset.Unspecified
		var lastSize = SizeUnspecified
		var lastSize by mutableStateOf(SizeUnspecified)
		var lastScale = Scale.Unspecified
		var lastAlpha = AlphaUnspecified

		@@ -410,7 +410,6 @@ internal class ElementNode(

		val placeable =
		measure(layoutImpl, element, transition, stateInContent, measurable, constraints)
		stateInContent.lastSize = placeable.size()
		return layout(placeable.width, placeable.height) { place(elementState, placeable) }
		}

		@@ -1214,6 +1213,7 @@ private fun measure(
		maybePlaceable?.let { placeable ->
		stateInContent.sizeBeforeInterruption = Element.SizeUnspecified
		stateInContent.sizeInterruptionDelta = IntSize.Zero
		stateInContent.lastSize = placeable.size()
		return placeable
		}

		@@ -1236,6 +1236,9 @@ private fun measure(
		)
		},
		)

		stateInContent.lastSize = interruptedSize

		return measurable.measure(
		Constraints.fixed(
		interruptedSize.width.coerceAtLeast(0),

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

+11 −0

Original line number	Diff line number	Diff line
		@@ -159,6 +159,17 @@ interface ElementStateScope {
		*/
		fun ElementKey.targetSize(content: ContentKey): IntSize?

		/**
		* Return the last known size of [this] element in the given [content], i.e. the size of the
		* element, or `null` if the element is not composed and measured in that content (yet).
		*
		* Note: Usually updated after the measurement pass and after processing children. However,
		* if the target size is known in advance (like during transitions involving transformations
		* or shared elements), the update happens before measurement pass. This earlier update
		* allows children to potentially use this predetermined size during their own measurement.
		*/
		fun ElementKey.lastSize(content: ContentKey): IntSize?

		/**
		* Return the target offset of [this] element in the given [content], i.e. the size of the
		* element when idle, or `null` if the element is not composed and placed in that content (yet).

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

+6 −0

Original line number	Diff line number	Diff line
		@@ -31,6 +31,12 @@ internal class ElementStateScopeImpl(private val layoutImpl: SceneTransitionLayo
		}
		}

		override fun ElementKey.lastSize(content: ContentKey): IntSize? {
		return layoutImpl.elements[this]?.stateByContent?.get(content)?.lastSize.takeIf {
		it != Element.SizeUnspecified
		}
		}

		override fun ElementKey.targetOffset(content: ContentKey): Offset? {
		return layoutImpl.elements[this]?.stateByContent?.get(content)?.targetOffset.takeIf {
		it != Offset.Unspecified

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

+96 −0

Original line number	Diff line number	Diff line
		@@ -51,6 +51,7 @@ import androidx.compose.ui.platform.LocalDensity
		import androidx.compose.ui.platform.LocalViewConfiguration
		import androidx.compose.ui.platform.testTag
		import androidx.compose.ui.test.assertIsDisplayed
		import androidx.compose.ui.test.assertIsEqualTo
		import androidx.compose.ui.test.assertIsNotDisplayed
		import androidx.compose.ui.test.assertPositionInRootIsEqualTo
		import androidx.compose.ui.test.assertTopPositionInRootIsEqualTo
		@@ -2312,4 +2313,99 @@ class ElementTest {

		assertThat(compositions).isEqualTo(1)
		}

		@Test
		fun measureElementApproachSizeBeforeChildren() {
		val state =
		rule.runOnUiThread {
		MutableSceneTransitionLayoutStateForTests(SceneA, SceneTransitions.Empty)
		}

		lateinit var lastFooHeight: () -> Dp?
		var firstFooHeightBeforeMeasuringChild: Dp? = null

		val scope =
		rule.setContentAndCreateMainScope {
		val density = LocalDensity.current
		SceneTransitionLayoutForTesting(state) {
		scene(SceneA) {
		SideEffect {
		lastFooHeight = {
		with(density) { TestElements.Foo.lastSize(SceneA)?.height?.toDp() }
		}
		}
		Box(Modifier.element(TestElements.Foo).size(200.dp)) {
		Box(
		Modifier.approachLayout(
		isMeasurementApproachInProgress = { false },
		approachMeasure = { measurable, constraints ->
		if (firstFooHeightBeforeMeasuringChild == null) {
		firstFooHeightBeforeMeasuringChild = lastFooHeight()
		}

		measurable.measure(constraints).run {
		layout(width, height) {}
		}
		},
		)
		)
		}
		}
		scene(SceneB) { Box(Modifier.element(TestElements.Foo).size(100.dp)) }
		}
		}

		var progress by mutableFloatStateOf(0f)
		val transition = transition(from = SceneA, to = SceneB, progress = { progress })

		fun assertDp(actual: Dp?, expected: Dp, subject: String) {
		assertThat(actual).isNotNull()
		actual!!.assertIsEqualTo(expected, subject, tolerance = 0.5.dp)
		}

		// Idle state: Scene A.
		assertThat(state.isTransitioning()).isFalse()
		assertDp(actual = lastFooHeight(), expected = 200.dp, subject = "lastFooHeight")

		// Start transition: Scene A -> Scene B (progress 0%).
		firstFooHeightBeforeMeasuringChild = null
		scope.launch { state.startTransition(transition) }
		rule.waitForIdle()
		assertThat(state.isTransitioning()).isTrue()
		assertDp(
		actual = firstFooHeightBeforeMeasuringChild,
		expected = 200.dp,
		subject = "firstFooHeightBeforeMeasuringChild",
		)
		assertDp(actual = lastFooHeight(), expected = 200.dp, subject = "lastFooHeight")

		// progress 50%: height is going from 200dp to 100dp, so 150dp is expected now.
		firstFooHeightBeforeMeasuringChild = null
		progress = 0.5f
		rule.waitForIdle()
		assertDp(
		actual = firstFooHeightBeforeMeasuringChild,
		expected = 150.dp,
		subject = "firstFooHeightBeforeMeasuringChild",
		)
		assertDp(actual = lastFooHeight(), expected = 150.dp, subject = "lastFooHeight")

		firstFooHeightBeforeMeasuringChild = null
		progress = 1f
		rule.waitForIdle()
		assertDp(
		actual = firstFooHeightBeforeMeasuringChild,
		expected = 100.dp,
		subject = "firstFooHeightBeforeMeasuringChild",
		)
		assertDp(actual = lastFooHeight(), expected = 100.dp, subject = "lastFooHeight")

		firstFooHeightBeforeMeasuringChild = null
		transition.finish()
		rule.waitForIdle()
		assertThat(state.isTransitioning()).isFalse()
		assertThat(firstFooHeightBeforeMeasuringChild).isNull()
		// null because SceneA does not exist anymore.
		assertThat(lastFooHeight()).isNull()
		}
		}