1 /*
2  * Copyright (C) 2023 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.systemui.keyguard.ui.viewmodel
18 
19 import com.android.app.animation.Interpolators.EMPHASIZED_ACCELERATE
20 import com.android.systemui.dagger.SysUISingleton
21 import com.android.systemui.keyguard.domain.interactor.FromLockscreenTransitionInteractor.Companion.TO_OCCLUDED_DURATION
22 import com.android.systemui.keyguard.domain.interactor.KeyguardTransitionInteractor
23 import com.android.systemui.keyguard.ui.KeyguardTransitionAnimationFlow
24 import javax.inject.Inject
25 import kotlin.time.Duration.Companion.milliseconds
26 import kotlinx.coroutines.flow.Flow
27 
28 /**
29  * Breaks down LOCKSCREEN->OCCLUDED transition into discrete steps for corresponding views to
30  * consume.
31  */
32 @SysUISingleton
33 class LockscreenToOccludedTransitionViewModel
34 @Inject
35 constructor(
36     private val interactor: KeyguardTransitionInteractor,
37 ) {
38     private val transitionAnimation =
39         KeyguardTransitionAnimationFlow(
40             transitionDuration = TO_OCCLUDED_DURATION,
41             transitionFlow = interactor.lockscreenToOccludedTransition,
42         )
43 
44     /** Lockscreen views alpha */
45     val lockscreenAlpha: Flow<Float> =
46         transitionAnimation.createFlow(
47             duration = 250.milliseconds,
48             onStep = { 1f - it },
49         )
50 
51     /** Lockscreen views y-translation */
52     fun lockscreenTranslationY(translatePx: Int): Flow<Float> {
53         return transitionAnimation.createFlow(
54             duration = TO_OCCLUDED_DURATION,
55             onStep = { value -> value * translatePx },
56             // Reset on cancel or finish
57             onFinish = { 0f },
58             onCancel = { 0f },
59             interpolator = EMPHASIZED_ACCELERATE,
60         )
61     }
62 }
63