Add `MotionSpec.Undefined` to delay initialization of MotionValue. (b64e01d4) · Commits · e / os / android_frameworks_libs_systemui

mechanics/src/com/android/mechanics/impl/Computations.kt

+86 −36

Original line number	Diff line number	Diff line
		@@ -39,17 +39,27 @@ internal abstract class Computations : CurrentFrameInput, LastFrameState, Static
		)

		// currentComputedValues input
		private var memoizedSpec: MotionSpec? = null
		private var memoizedSpec: MotionSpec = MotionSpec.InitiallyUndefined
		private var memoizedInput: Float = Float.MIN_VALUE
		private var memoizedAnimationTimeNanos: Long = Long.MIN_VALUE
		private var memoizedDirection: InputDirection = InputDirection.Min

		// currentComputedValues output
		private lateinit var memoizedComputedValues: ComputedValues
		private var memoizedComputedValues: ComputedValues =
		ComputedValues(
		MotionSpec.InitiallyUndefined.segmentAtInput(memoizedInput, memoizedDirection),
		GuaranteeState.Inactive,
		DiscontinuityAnimation.None,
		)

		internal val currentComputedValues: ComputedValues
		get() {
		val currentSpec: MotionSpec = spec
		if (currentSpec == MotionSpec.InitiallyUndefined) {
		requireNoMotionSpecSet()
		return memoizedComputedValues
		}

		val currentInput: Float = currentInput
		val currentAnimationTimeNanos: Long = currentAnimationTimeNanos
		val currentDirection: InputDirection = currentDirection
		@@ -63,11 +73,21 @@ internal abstract class Computations : CurrentFrameInput, LastFrameState, Static
		return memoizedComputedValues
		}

		val isInitialComputation = memoizedSpec == MotionSpec.InitiallyUndefined

		memoizedSpec = currentSpec
		memoizedInput = currentInput
		memoizedAnimationTimeNanos = currentAnimationTimeNanos
		memoizedDirection = currentDirection

		memoizedComputedValues =
		if (isInitialComputation) {
		ComputedValues(
		currentSpec.segmentAtInput(currentInput, currentDirection),
		GuaranteeState.Inactive,
		DiscontinuityAnimation.None,
		)
		} else {
		val segment: SegmentData =
		computeSegmentData(
		spec = currentSpec,
		@@ -99,9 +119,9 @@ internal abstract class Computations : CurrentFrameInput, LastFrameState, Static
		animationTimeNanos = currentAnimationTimeNanos,
		)

		return ComputedValues(segment, guarantee, animation).also {
		memoizedComputedValues = it
		ComputedValues(segment, guarantee, animation)
		}
		return memoizedComputedValues
		}

		// currentSpringState input
		@@ -613,4 +633,34 @@ internal abstract class Computations : CurrentFrameInput, LastFrameState, Static
		}
		}
		}

		/**
		* Precondition to ensure that this [Computations] has not yet been initialized with a
		* MotionSpec other than [MotionSpec.InitiallyUndefined].
		*
		* This precondition is added since the desired behavior of the MotionValue when toggling back
		* to a [MotionSpec.InitiallyUndefined] spec is unclear. If there is a compelling usecase, this
		* restriction could be lifted.
		*/
		private fun requireNoMotionSpecSet() {
		// A MotionValue's spec can be MotionValue.Undefined initially. However, once a real spec
		// has been set, it cannot be changed back to MotionValue.Undefined.

		require(memoizedSpec == MotionSpec.InitiallyUndefined) {
		// memoizedSpec is only ever Undefined initially, before a motionSpec was set.
		// This is used as a signal to detect if a user switches back to Undefined.
		"MotionSpec must not be changed back to undefined!\n" +
		" MotionValue: $label\n" +
		" last MotionSpec: $memoizedSpec"
		}

		// memoizedComputedValues must not have been reassigned either.
		require(
		with(memoizedComputedValues) {
		segment.spec == MotionSpec.InitiallyUndefined &&
		guarantee == GuaranteeState.Inactive &&
		animation == DiscontinuityAnimation.None
		}
		)
		}
		}

mechanics/src/com/android/mechanics/spec/MotionSpec.kt

+30 −0

Original line number	Diff line number	Diff line
		@@ -150,6 +150,19 @@ data class MotionSpec(

		/* Empty motion spec, the output is the same as the input. */
		val Empty = MotionSpec(DirectionalMotionSpec.Empty)

		/**
		* Placeholder to indicate that a [MotionSpec] cannot be supplied yet.
		*
		* As long as this spec is set, the MotionValue output is NaN. When the MotionValue is first
		* supplied with an actual spec, the output value will be set immediately, without an
		* animation.
		*
		* This must only ever be supplied as a spec for new `MotionValue`s, which never were
		* supplied any other spec. Supplying this [InitiallyUndefined] spec to a MotionValue that
		* has already been supplied a spec will throw an exception.
		*/
		val InitiallyUndefined = MotionSpec(DirectionalMotionSpec.InitiallyUndefined)
		}
		}

		@@ -247,5 +260,22 @@ data class DirectionalMotionSpec(
		listOf(Breakpoint.minLimit, Breakpoint.maxLimit),
		listOf(Mapping.Identity),
		)

		/** Internal marker for [MotionSpec.InitiallyUndefined]. */
		internal val InitiallyUndefined =
		DirectionalMotionSpec(
		listOf(Breakpoint.minLimit, Breakpoint.maxLimit),
		listOf(
		object : Mapping {
		override fun map(input: Float): Float {
		return Float.NaN
		}

		override fun toString(): String {
		return "InitiallyUndefined"
		}
		}
		),
		)
		}
		}

mechanics/src/com/android/mechanics/view/ViewMotionValue.kt

+3 −3

Original line number	Diff line number	Diff line
		@@ -222,9 +222,9 @@ private class ImperativeComputations(
		repeatMode = ValueAnimator.RESTART
		repeatCount = ValueAnimator.INFINITE
		start()
		pause()
		addUpdateListener {
		val isAnimationFinished = updateOutputValue(currentPlayTime)
		debugInspector?.isAnimating = !isAnimationFinished
		if (isAnimationFinished) {
		pause()
		}
		@@ -234,14 +234,12 @@ private class ImperativeComputations(
		fun ensureFrameRequested() {
		if (animationFrameDriver.isPaused) {
		animationFrameDriver.resume()
		debugInspector?.isAnimating = true
		}
		}

		fun pauseFrameRequests() {
		if (animationFrameDriver.isRunning) {
		animationFrameDriver.pause()
		debugInspector?.isAnimating = false
		}
		}

		@@ -290,6 +288,8 @@ private class ImperativeComputations(
		)
		}

		if (currentValues.segment.spec == MotionSpec.InitiallyUndefined) return true

		listeners.fastForEach { it.onMotionValueUpdated(motionValue) }

		// Prepare last* state

mechanics/tests/goldens/unspecifiedSpec_atTheBeginning_jumpcutsToFirstValue.json

0 → 100644

+92 −0

Original line number	Diff line number	Diff line
		{
		"frame_ids": [
		0,
		16,
		32,
		48,
		64
		],
		"features": [
		{
		"name": "input",
		"type": "float",
		"data_points": [
		0,
		5,
		10,
		15,
		20
		]
		},
		{
		"name": "gestureDirection",
		"type": "string",
		"data_points": [
		"Max",
		"Max",
		"Max",
		"Max",
		"Max"
		]
		},
		{
		"name": "output",
		"type": "float",
		"data_points": [
		"NaN",
		"NaN",
		"NaN",
		15,
		20
		]
		},
		{
		"name": "outputTarget",
		"type": "float",
		"data_points": [
		"NaN",
		"NaN",
		"NaN",
		15,
		20
		]
		},
		{
		"name": "outputSpring",
		"type": "springParameters",
		"data_points": [
		{
		"stiffness": 100000,
		"dampingRatio": 1
		},
		{
		"stiffness": 100000,
		"dampingRatio": 1
		},
		{
		"stiffness": 100000,
		"dampingRatio": 1
		},
		{
		"stiffness": 100000,
		"dampingRatio": 1
		},
		{
		"stiffness": 100000,
		"dampingRatio": 1
		}
		]
		},
		{
		"name": "isStable",
		"type": "boolean",
		"data_points": [
		true,
		true,
		true,
		true,
		true
		]
		}
		]
		}
		No newline at end of file

mechanics/tests/goldens/unspecifiedSpec_outputIsNan.json

0 → 100644

+102 −0

Original line number	Diff line number	Diff line
		{
		"frame_ids": [
		0,
		16,
		32,
		48,
		64,
		80
		],
		"features": [
		{
		"name": "input",
		"type": "float",
		"data_points": [
		0,
		20,
		40,
		60,
		80,
		100
		]
		},
		{
		"name": "gestureDirection",
		"type": "string",
		"data_points": [
		"Max",
		"Max",
		"Max",
		"Max",
		"Max",
		"Max"
		]
		},
		{
		"name": "output",
		"type": "float",
		"data_points": [
		"NaN",
		"NaN",
		"NaN",
		"NaN",
		"NaN",
		"NaN"
		]
		},
		{
		"name": "outputTarget",
		"type": "float",
		"data_points": [
		"NaN",
		"NaN",
		"NaN",
		"NaN",
		"NaN",
		"NaN"
		]
		},
		{
		"name": "outputSpring",
		"type": "springParameters",
		"data_points": [
		{
		"stiffness": 100000,
		"dampingRatio": 1
		},
		{
		"stiffness": 100000,
		"dampingRatio": 1
		},
		{
		"stiffness": 100000,
		"dampingRatio": 1
		},
		{
		"stiffness": 100000,
		"dampingRatio": 1
		},
		{
		"stiffness": 100000,
		"dampingRatio": 1
		},
		{
		"stiffness": 100000,
		"dampingRatio": 1
		}
		]
		},
		{
		"name": "isStable",
		"type": "boolean",
		"data_points": [
		true,
		true,
		true,
		true,
		true,
		true
		]
		}
		]
		}
		No newline at end of file