1 /*
2 * Copyright (C) 2024 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 package com.android.compose.animation.scene
18
19 import androidx.compose.animation.core.Animatable
20 import androidx.compose.animation.core.AnimationVector1D
21 import androidx.compose.animation.core.SpringSpec
22 import androidx.compose.material3.ExperimentalMaterial3ExpressiveApi
23 import androidx.compose.runtime.withFrameNanos
24 import com.android.compose.animation.scene.content.state.TransitionState
25 import kotlinx.coroutines.CoroutineScope
26 import kotlinx.coroutines.Job
27
animateContentnull28 internal fun CoroutineScope.animateContent(
29 layoutState: MutableSceneTransitionLayoutStateImpl,
30 transition: TransitionState.Transition,
31 oneOffAnimation: OneOffAnimation,
32 targetProgress: Float,
33 chain: Boolean = true,
34 ): Job {
35 oneOffAnimation.onRun = {
36 // Animate the progress to its target value.
37 @OptIn(ExperimentalMaterial3ExpressiveApi::class)
38 val animationSpec =
39 transition.transformationSpec.progressSpec
40 ?: layoutState.motionScheme.defaultSpatialSpec()
41 val visibilityThreshold =
42 (animationSpec as? SpringSpec)?.visibilityThreshold ?: ProgressVisibilityThreshold
43 val replacedTransition = transition.replacedTransition
44 val initialProgress = replacedTransition?.progress ?: 0f
45 val initialVelocity = replacedTransition?.progressVelocity ?: 0f
46 val animatable =
47 Animatable(initialProgress, visibilityThreshold = visibilityThreshold).also {
48 oneOffAnimation.animatable = it
49 }
50
51 if (layoutState.deferTransitionProgress) {
52 // Defer the animation by one frame so that the transition progress is changed only when
53 // the expensive first composition frame is done.
54 withFrameNanos {}
55 }
56 animatable.animateTo(targetProgress, animationSpec, initialVelocity)
57 }
58
59 return layoutState.startTransitionImmediately(animationScope = this, transition, chain)
60 }
61
62 internal class OneOffAnimation {
63 /**
64 * The animatable used to animate this transition.
65 *
66 * Note: This is lateinit because we need to first create this object so that
67 * [SceneTransitionLayoutState] can compute the transformations and animation spec associated to
68 * the transition, which is needed to initialize this Animatable.
69 */
70 lateinit var animatable: Animatable<Float, AnimationVector1D>
71
72 /** The runnable to run for this animation. */
73 lateinit var onRun: suspend () -> Unit
74
75 val progress: Float
76 get() = animatable.value
77
78 val progressVelocity: Float
79 get() = animatable.velocity
80
runnull81 suspend fun run() {
82 onRun()
83 }
84
freezeAndAnimateToCurrentStatenull85 fun freezeAndAnimateToCurrentState() {
86 // Do nothing, the state of one-off animations never change and we directly animate to it.
87 }
88 }
89
90 // TODO(b/290184746): Compute a good default visibility threshold that depends on the layout size
91 // and screen density.
92 internal const val ProgressVisibilityThreshold = 1e-3f
93