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 com.android.compose.animation.scene.content.state.TransitionState
23 import kotlinx.coroutines.CoroutineScope
24 import kotlinx.coroutines.Job
25
animateContentnull26 internal fun CoroutineScope.animateContent(
27 layoutState: MutableSceneTransitionLayoutStateImpl,
28 transition: TransitionState.Transition,
29 oneOffAnimation: OneOffAnimation,
30 targetProgress: Float,
31 chain: Boolean = true,
32 ): Job {
33 oneOffAnimation.onRun = {
34 // Animate the progress to its target value.
35 val animationSpec = transition.transformationSpec.progressSpec
36 val visibilityThreshold =
37 (animationSpec as? SpringSpec)?.visibilityThreshold ?: ProgressVisibilityThreshold
38 val replacedTransition = transition.replacedTransition
39 val initialProgress = replacedTransition?.progress ?: 0f
40 val initialVelocity = replacedTransition?.progressVelocity ?: 0f
41 val animatable =
42 Animatable(initialProgress, visibilityThreshold = visibilityThreshold).also {
43 oneOffAnimation.animatable = it
44 }
45
46 animatable.animateTo(targetProgress, animationSpec, initialVelocity)
47 }
48
49 return layoutState.startTransitionImmediately(animationScope = this, transition, chain)
50 }
51
52 internal class OneOffAnimation {
53 /**
54 * The animatable used to animate this transition.
55 *
56 * Note: This is lateinit because we need to first create this object so that
57 * [SceneTransitionLayoutState] can compute the transformations and animation spec associated to
58 * the transition, which is needed to initialize this Animatable.
59 */
60 lateinit var animatable: Animatable<Float, AnimationVector1D>
61
62 /** The runnable to run for this animation. */
63 lateinit var onRun: suspend () -> Unit
64
65 val progress: Float
66 get() = animatable.value
67
68 val progressVelocity: Float
69 get() = animatable.velocity
70
runnull71 suspend fun run() {
72 onRun()
73 }
74
freezeAndAnimateToCurrentStatenull75 fun freezeAndAnimateToCurrentState() {
76 // Do nothing, the state of one-off animations never change and we directly animate to it.
77 }
78 }
79
80 // TODO(b/290184746): Compute a good default visibility threshold that depends on the layout size
81 // and screen density.
82 internal const val ProgressVisibilityThreshold = 1e-3f
83