1 /*
2  * Copyright (C) 2022 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_DECELERATE
20 import com.android.systemui.dagger.SysUISingleton
21 import com.android.systemui.keyguard.domain.interactor.FromOccludedTransitionInteractor.Companion.TO_LOCKSCREEN_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 OCCLUDED->LOCKSCREEN transition into discrete steps for corresponding views to
30  * consume.
31  */
32 @SysUISingleton
33 class OccludedToLockscreenTransitionViewModel
34 @Inject
35 constructor(
36     private val interactor: KeyguardTransitionInteractor,
37 ) {
38     private val transitionAnimation =
39         KeyguardTransitionAnimationFlow(
40             transitionDuration = TO_LOCKSCREEN_DURATION,
41             transitionFlow = interactor.occludedToLockscreenTransition,
42         )
43 
44     /** Lockscreen views y-translation */
45     fun lockscreenTranslationY(translatePx: Int): Flow<Float> {
46         return transitionAnimation.createFlow(
47             duration = TO_LOCKSCREEN_DURATION,
48             onStep = { value -> -translatePx + value * translatePx },
49             interpolator = EMPHASIZED_DECELERATE,
50             onCancel = { 0f },
51         )
52     }
53 
54     /** Lockscreen views alpha */
55     val lockscreenAlpha: Flow<Float> =
56         transitionAnimation.createFlow(
57             startTime = 233.milliseconds,
58             duration = 250.milliseconds,
59             onStep = { it },
60         )
61 }
62