Merge "MM: Introduce MotionValueNode" into main (deb0526d) · Commits · e / os / android_frameworks_libs_systemui

mechanics/compose/src/com/android/mechanics/compose/modifier/MotionValueNode.kt

0 → 100644

+124 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2025 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*/

		package com.android.mechanics.compose.modifier

		import androidx.compose.runtime.getValue
		import androidx.compose.runtime.mutableFloatStateOf
		import androidx.compose.runtime.mutableStateOf
		import androidx.compose.runtime.setValue
		import androidx.compose.ui.Modifier
		import androidx.compose.ui.node.DelegatingNode
		import androidx.compose.ui.node.ObserverModifierNode
		import androidx.compose.ui.node.observeReads
		import com.android.mechanics.GestureContext
		import com.android.mechanics.MotionValue
		import com.android.mechanics.MotionValue.Companion.StableThresholdEffect
		import com.android.mechanics.debug.MotionValueDebugger
		import com.android.mechanics.debug.findMotionValueDebugger
		import com.android.mechanics.spec.MotionSpec
		import kotlinx.coroutines.launch

		/**
		* A [Modifier.Node] that encapsulates a [MotionValue] and its lifecycle.
		*
		* This node observes an [input] value and drives a [MotionValue] animation based on a [MotionSpec].
		* It handles the creation, running, and cleanup of the motion value instance.
		*
		* Note: This is primarily intended to be used via the [DelegatingNode.delegate] function.
		*
		* @param input A lambda that provides the current input value for the motion.
		* @param gestureContext The context for gesture-driven animations.
		* @param initialSpec The initial [MotionSpec] to configure the animation.
		* @param label An optional label for debugging purposes.
		* @param stableThreshold The threshold to determine if the motion value is stable.
		* @param debug Whether this value needs to be registered to a [MotionValueDebugger].
		*/
		internal class MotionValueNode(
		private var input: () -> Float,
		gestureContext: GestureContext,
		initialSpec: MotionSpec = MotionSpec.Empty,
		label: String? = null,
		stableThreshold: Float = StableThresholdEffect,
		private val debug: Boolean = false,
		) : Modifier.Node(), ObserverModifierNode {
		private var currentInputState by mutableFloatStateOf(input())

		private val motionValue =
		MotionValue(
		currentInput = { currentInputState },
		gestureContext = gestureContext,
		initialSpec = initialSpec,
		label = label,
		stableThreshold = stableThreshold,
		)

		/**
		* Whether the output value of the [motionValue] is currently fixed.
		*
		* This is true if the animation is at rest and the current input maps to a fixed output that
		* has not changed, which can be used to prevent unnecessary recompositions or layouts.
		*/
		var isOutputFixed by mutableStateOf(motionValue.isOutputFixed)
		private set

		var output by mutableFloatStateOf(motionValue.output)
		private set

		override fun onAttach() {
		onObservedReadsChanged()

		coroutineScope.launch {
		val disposableHandle =
		if (debug) {
		findMotionValueDebugger()?.register(motionValue)
		} else {
		null
		}
		try {
		motionValue.keepRunning()
		} finally {
		disposableHandle?.dispose()
		}
		}
		}

		/**
		* This function is called by Compose whenever a state object that was read inside the
		* `observeReads` block has changed.
		*
		* Note: that this callback may not be invoked immediately, but can be deferred until a later
		* stage, such as after the measure and layout pass.
		*/
		override fun onObservedReadsChanged() {
		observeReads { updateStates() }
		}

		/** Reads the latest input and updates the internal states of this node. */
		private fun updateStates() {
		currentInputState = input()
		isOutputFixed = motionValue.isOutputFixed

		// Only invoke the update callback if the output might have changed.
		if (isOutputFixed) return

		output = motionValue.output
		}

		fun updateSpec(spec: MotionSpec) {
		motionValue.spec = spec
		}
		}

mechanics/compose/src/com/android/mechanics/compose/modifier/VerticalFadeContentRevealModifier.kt

+25 −47

Original line number	Diff line number	Diff line
		@@ -24,6 +24,7 @@ import androidx.compose.ui.layout.ApproachMeasureScope
		import androidx.compose.ui.layout.Measurable
		import androidx.compose.ui.layout.MeasureResult
		import androidx.compose.ui.layout.MeasureScope
		import androidx.compose.ui.node.DelegatingNode
		import androidx.compose.ui.node.ModifierNodeElement
		import androidx.compose.ui.node.ObserverModifierNode
		import androidx.compose.ui.node.observeReads
		@@ -38,16 +39,12 @@ import com.android.compose.animation.scene.ContentScope
		import com.android.compose.animation.scene.ElementKey
		import com.android.compose.animation.scene.content.state.TransitionState
		import com.android.compose.animation.scene.mechanics.gestureContextOrDefault
		import com.android.mechanics.MotionValue
		import com.android.mechanics.debug.findMotionValueDebugger
		import com.android.mechanics.effects.FixedValue
		import com.android.mechanics.spec.Mapping
		import com.android.mechanics.spec.MotionSpec
		import com.android.mechanics.spec.builder.MotionBuilderContext
		import com.android.mechanics.spec.builder.directionalMotionSpec
		import com.android.mechanics.spec.builder.effectsMotionSpec
		import kotlinx.coroutines.Job
		import kotlinx.coroutines.launch

		/**
		* This component remains hidden until it reach its target height.
		@@ -115,21 +112,24 @@ private class FadeContentRevealNode(
		private var container: ElementKey,
		private var deltaY: Float,
		label: String?,
		private val debug: Boolean,
		) : Modifier.Node(), ApproachLayoutModifierNode, ObserverModifierNode {
		debug: Boolean,
		) : DelegatingNode(), ApproachLayoutModifierNode, ObserverModifierNode {

		private val motionValue =
		MotionValue(
		currentInput = {
		private val motionValueNode: MotionValueNode =
		delegate(
		MotionValueNode(
		input = {
		with(contentScope) {
		val containerHeight =
		container.lastSize(contentKey)?.height ?: return@MotionValue 0f
		container.lastSize(contentKey)?.height ?: return@MotionValueNode 0f
		containerHeight + deltaY
		}
		},
		initialSpec = MotionSpec(directionalMotionSpec(Mapping.Zero)),
		gestureContext = contentScope.gestureContextOrDefault(),
		initialSpec = MotionSpec(directionalMotionSpec(Mapping.Zero)),
		label = "FadeContentReveal(${label.orEmpty()})",
		debug = debug,
		)
		)

		fun update(
		@@ -145,29 +145,8 @@ private class FadeContentRevealNode(
		updateMotionSpec(contentScope.layoutState.transitionState)
		}

		private var motionValueJob: Job? = null

		override fun onAttach() {
		onObservedReadsChanged()

		motionValueJob =
		coroutineScope.launch {
		val disposableHandle =
		if (debug) {
		findMotionValueDebugger()?.register(motionValue)
		} else {
		null
		}
		try {
		motionValue.keepRunning()
		} finally {
		disposableHandle?.dispose()
		}
		}
		}

		override fun onDetach() {
		motionValueJob?.cancel()
		}

		override fun onObservedReadsChanged() {
		@@ -175,19 +154,16 @@ private class FadeContentRevealNode(
		}

		private var targetBounds = Rect.Zero
		private var isContentTransition = false

		private fun updateMotionSpec(transitionState: TransitionState) {
		isContentTransition = transitionState is TransitionState.Transition

		val height = targetBounds.height
		if (height == 0f) {
		// We cannot compute specs for height 0.
		motionValue.spec = MotionSpec(directionalMotionSpec(Mapping.Fixed(0f)))
		motionValueNode.updateSpec(MotionSpec(directionalMotionSpec(Mapping.Fixed(0f))))
		return
		}

		motionValue.spec =
		motionValueNode.updateSpec(
		when (transitionState) {
		is TransitionState.Idle -> {
		val containerMinHeight = 0
		@@ -206,16 +182,18 @@ private class FadeContentRevealNode(
		}
		MotionSpec(directionalMotionSpec(Mapping.Fixed(if (isRevealed) 1f else 0f)))
		}

		is TransitionState.Transition -> {
		motionBuilderContext.effectsMotionSpec(Mapping.Zero) {
		after(targetBounds.bottom, FixedValue.One)
		}
		}
		}
		)
		}

		override fun isMeasurementApproachInProgress(lookaheadSize: IntSize): Boolean {
		return isContentTransition \|\| !motionValue.isStable
		return !motionValueNode.isOutputFixed
		}

		override fun MeasureScope.measure(
		@@ -245,7 +223,7 @@ private class FadeContentRevealNode(
		): MeasureResult {
		return measurable.measure(constraints).run {
		layout(width, height) {
		val revealAlpha = motionValue.output
		val revealAlpha = motionValueNode.output.fastCoerceAtLeast(0f)
		if (revealAlpha < 1) {
		placeWithLayer(IntOffset.Zero) {
		alpha = revealAlpha.fastCoerceAtLeast(0f)

mechanics/compose/src/com/android/mechanics/compose/modifier/VerticalTactileSurfaceRevealModifier.kt

+26 −47

Original line number	Diff line number	Diff line
		@@ -24,6 +24,7 @@ import androidx.compose.ui.layout.ApproachMeasureScope
		import androidx.compose.ui.layout.Measurable
		import androidx.compose.ui.layout.MeasureResult
		import androidx.compose.ui.layout.MeasureScope
		import androidx.compose.ui.node.DelegatingNode
		import androidx.compose.ui.node.ModifierNodeElement
		import androidx.compose.ui.node.ObserverModifierNode
		import androidx.compose.ui.node.observeReads
		@@ -39,8 +40,6 @@ import com.android.compose.animation.scene.ContentScope
		import com.android.compose.animation.scene.ElementKey
		import com.android.compose.animation.scene.content.state.TransitionState
		import com.android.compose.animation.scene.mechanics.gestureContextOrDefault
		import com.android.mechanics.MotionValue
		import com.android.mechanics.debug.findMotionValueDebugger
		import com.android.mechanics.effects.RevealOnThreshold
		import com.android.mechanics.spec.Mapping
		import com.android.mechanics.spec.MotionSpec
		@@ -48,8 +47,6 @@ import com.android.mechanics.spec.builder.MotionBuilderContext
		import com.android.mechanics.spec.builder.directionalMotionSpec
		import com.android.mechanics.spec.builder.spatialMotionSpec
		import kotlin.math.roundToInt
		import kotlinx.coroutines.Job
		import kotlinx.coroutines.launch

		/**
		* This component remains hidden until its target height meets a minimum threshold. At that point,
		@@ -127,22 +124,25 @@ private class VerticalTactileSurfaceRevealNode(
		private var deltaY: Float,
		private var revealOnThreshold: RevealOnThreshold,
		label: String?,
		private val debug: Boolean,
		) : Modifier.Node(), ApproachLayoutModifierNode, ObserverModifierNode {
		debug: Boolean,
		) : DelegatingNode(), ApproachLayoutModifierNode, ObserverModifierNode {

		private val motionValue =
		MotionValue(
		currentInput = {
		private val motionValueNode: MotionValueNode =
		delegate(
		MotionValueNode(
		input = {
		with(contentScope) {
		val containerHeight =
		container.lastSize(contentKey)?.height ?: return@MotionValue 0f
		container.lastSize(contentKey)?.height ?: return@MotionValueNode 0f
		containerHeight + deltaY
		}
		},
		initialSpec = MotionSpec(directionalMotionSpec(Mapping.Zero)),
		gestureContext = contentScope.gestureContextOrDefault(),
		initialSpec = MotionSpec(directionalMotionSpec(Mapping.Zero)),
		label = "TactileSurfaceReveal(${label.orEmpty()})",
		stableThreshold = MotionBuilderContext.StableThresholdSpatial,
		debug = debug,
		)
		)

		fun update(
		@@ -160,29 +160,8 @@ private class VerticalTactileSurfaceRevealNode(
		updateMotionSpec(contentScope.layoutState.transitionState)
		}

		private var motionValueJob: Job? = null

		override fun onAttach() {
		onObservedReadsChanged()

		motionValueJob =
		coroutineScope.launch {
		val disposableHandle =
		if (debug) {
		findMotionValueDebugger()?.register(motionValue)
		} else {
		null
		}
		try {
		motionValue.keepRunning()
		} finally {
		disposableHandle?.dispose()
		}
		}
		}

		override fun onDetach() {
		motionValueJob?.cancel()
		}

		override fun onObservedReadsChanged() {
		@@ -190,19 +169,16 @@ private class VerticalTactileSurfaceRevealNode(
		}

		private var targetBounds = Rect.Zero
		private var isContentTransition = false

		private fun updateMotionSpec(transitionState: TransitionState) {
		isContentTransition = transitionState is TransitionState.Transition

		val height = targetBounds.height
		if (height == 0f) {
		// We cannot compute specs for height 0.
		motionValue.spec = MotionSpec(directionalMotionSpec(Mapping.Fixed(0f)))
		motionValueNode.updateSpec(MotionSpec(directionalMotionSpec(Mapping.Fixed(0f))))
		return
		}

		motionValue.spec =
		motionValueNode.updateSpec(
		when (transitionState) {
		is TransitionState.Idle -> {
		val containerMinHeight = 0
		@@ -221,6 +197,7 @@ private class VerticalTactileSurfaceRevealNode(
		}
		MotionSpec(directionalMotionSpec(Mapping.Fixed(if (isRevealed) height else 0f)))
		}

		is TransitionState.Transition -> {
		motionBuilderContext.spatialMotionSpec(Mapping.Zero) {
		between(
		@@ -231,10 +208,11 @@ private class VerticalTactileSurfaceRevealNode(
		}
		}
		}
		)
		}

		override fun isMeasurementApproachInProgress(lookaheadSize: IntSize): Boolean {
		return isContentTransition \|\| !motionValue.isStable
		return !motionValueNode.isOutputFixed
		}

		override fun MeasureScope.measure(
		@@ -262,7 +240,8 @@ private class VerticalTactileSurfaceRevealNode(
		measurable: Measurable,
		constraints: Constraints,
		): MeasureResult {
		val height = motionValue.output.roundToInt().fastCoerceAtLeast(0)
		val height = motionValueNode.output.roundToInt().fastCoerceAtLeast(0)

		val animatedConstraints = constraints.copy(maxHeight = height)
		return measurable.measure(animatedConstraints).run {
		layout(width, height) {

mechanics/compose/tests/goldens/verticalTactileSurfaceReveal_gesture_flingClose.json

+7 −7

Original line number	Diff line number	Diff line
		@@ -295,7 +295,7 @@
		50,
		38.8,
		18.4,
		1.2,
		4.8,
		0,
		0,
		0,
		@@ -341,7 +341,7 @@
		120,
		108.8,
		88.4,
		71.2,
		74.8,
		65.2,
		53.6,
		44.4,
		@@ -433,7 +433,7 @@
		132.8,
		116.8,
		96.4,
		79.2,
		82.8,
		73.2,
		61.6,
		52.4,
		@@ -525,7 +525,7 @@
		140.8,
		124.8,
		104.4,
		87.2,
		90.8,
		81.2,
		69.6,
		60.4,
		@@ -617,7 +617,7 @@
		148.8,
		132.8,
		112.4,
		95.2,
		98.8,
		89.2,
		77.6,
		68.4,
		@@ -709,7 +709,7 @@
		156.8,
		140.8,
		120.4,
		103.2,
		106.8,
		97.2,
		85.6,
		76.4,
		@@ -801,7 +801,7 @@
		164.8,
		148.8,
		128.4,
		111.2,
		114.8,
		105.2,
		93.6,
		84.4,

mechanics/compose/tests/goldens/verticalTactileSurfaceReveal_gesture_flingOpen.json

+8 −8

Original line number	Diff line number	Diff line
		@@ -240,7 +240,7 @@
		"type": "not_found"
		},
		0,
		10.8,
		10.4,
		21.2,
		29.2,
		44.4,
		@@ -302,7 +302,7 @@
		"type": "not_found"
		},
		12,
		22.8,
		22.4,
		33.2,
		41.2,
		56.4,
		@@ -426,7 +426,7 @@
		"type": "not_found"
		},
		20,
		30.8,
		30.4,
		41.2,
		49.2,
		64.4,
		@@ -550,7 +550,7 @@
		"type": "not_found"
		},
		28,
		38.8,
		38.4,
		49.2,
		57.2,
		72.4,
		@@ -674,7 +674,7 @@
		"type": "not_found"
		},
		36,
		46.8,
		46.4,
		57.2,
		65.2,
		80.4,
		@@ -798,7 +798,7 @@
		"type": "not_found"
		},
		44,
		54.8,
		54.4,
		65.2,
		73.2,
		88.4,
		@@ -922,7 +922,7 @@
		"type": "not_found"
		},
		52,
		62.8,
		62.4,
		73.2,
		81.2,
		96.4,
		@@ -1046,7 +1046,7 @@
		"type": "not_found"
		},
		60,
		70.8,
		70.4,
		81.2,
		89.2,
		104.4,