| Anthony Robledo | 8db013f | 2021-10-18 11:35:53 -0400 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2021 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 androidx.compose.material3 |
| 18 | |
| 19 | import androidx.compose.animation.core.Animatable |
| 20 | import androidx.compose.animation.core.AnimationSpec |
| 21 | import androidx.compose.animation.core.CubicBezierEasing |
| 22 | import androidx.compose.animation.core.Easing |
| 23 | import androidx.compose.animation.core.FastOutSlowInEasing |
| 24 | import androidx.compose.animation.core.TweenSpec |
| 25 | import androidx.compose.foundation.interaction.DragInteraction |
| 26 | import androidx.compose.foundation.interaction.FocusInteraction |
| 27 | import androidx.compose.foundation.interaction.HoverInteraction |
| 28 | import androidx.compose.foundation.interaction.Interaction |
| 29 | import androidx.compose.foundation.interaction.PressInteraction |
| 30 | import androidx.compose.ui.unit.Dp |
| 31 | |
| 32 | /** |
| 33 | * Animates the [Dp] value of [this] between [from] and [to] [Interaction]s, to [target]. The |
| 34 | * [AnimationSpec] used depends on the values for [from] and [to], see |
| 35 | * [ElevationDefaults.incomingAnimationSpecForInteraction] and |
| 36 | * [ElevationDefaults.outgoingAnimationSpecForInteraction] for more details. |
| 37 | * |
| 38 | * @param target the [Dp] target elevation for this component, corresponding to the elevation |
| 39 | * desired for the [to] state. |
| 40 | * @param from the previous [Interaction] that was used to calculate elevation. `null` if there |
| 41 | * was no previous [Interaction], such as when the component is in its default state. |
| 42 | * @param to the [Interaction] that this component is moving to, such as [PressInteraction.Press] |
| 43 | * when this component is being pressed. `null` if this component is moving back to its default |
| 44 | * state. |
| 45 | */ |
| 46 | internal suspend fun Animatable<Dp, *>.animateElevation( |
| 47 | target: Dp, |
| 48 | from: Interaction? = null, |
| 49 | to: Interaction? = null |
| 50 | ) { |
| 51 | val spec = when { |
| 52 | // Moving to a new state |
| 53 | to != null -> ElevationDefaults.incomingAnimationSpecForInteraction(to) |
| 54 | // Moving to default, from a previous state |
| 55 | from != null -> ElevationDefaults.outgoingAnimationSpecForInteraction(from) |
| 56 | // Loading the initial state, or moving back to the baseline state from a disabled / |
| 57 | // unknown state, so just snap to the final value. |
| 58 | else -> null |
| 59 | } |
| 60 | if (spec != null) animateTo(target, spec) else snapTo(target) |
| 61 | } |
| 62 | |
| 63 | /** |
| 64 | * Contains default [AnimationSpec]s used for animating elevation between different [Interaction]s. |
| 65 | * |
| 66 | * Typically you should use [animateElevation] instead, which uses these [AnimationSpec]s |
| 67 | * internally. [animateElevation] in turn is used by the defaults for cards and buttons. |
| 68 | * |
| 69 | * @see animateElevation |
| 70 | */ |
| 71 | private object ElevationDefaults { |
| 72 | /** |
| 73 | * Returns the [AnimationSpec]s used when animating elevation to [interaction], either from a |
| 74 | * previous [Interaction], or from the default state. If [interaction] is unknown, then |
| 75 | * returns `null`. |
| 76 | * |
| 77 | * @param interaction the [Interaction] that is being animated to |
| 78 | */ |
| 79 | fun incomingAnimationSpecForInteraction(interaction: Interaction): AnimationSpec<Dp>? { |
| 80 | return when (interaction) { |
| 81 | is PressInteraction.Press -> DefaultIncomingSpec |
| 82 | is DragInteraction.Start -> DefaultIncomingSpec |
| 83 | is HoverInteraction.Enter -> DefaultIncomingSpec |
| 84 | is FocusInteraction.Focus -> DefaultIncomingSpec |
| 85 | else -> null |
| 86 | } |
| 87 | } |
| 88 | |
| 89 | /** |
| 90 | * Returns the [AnimationSpec]s used when animating elevation away from [interaction], to the |
| 91 | * default state. If [interaction] is unknown, then returns `null`. |
| 92 | * |
| 93 | * @param interaction the [Interaction] that is being animated away from |
| 94 | */ |
| 95 | fun outgoingAnimationSpecForInteraction(interaction: Interaction): AnimationSpec<Dp>? { |
| 96 | return when (interaction) { |
| 97 | is PressInteraction.Press -> DefaultOutgoingSpec |
| 98 | is DragInteraction.Start -> DefaultOutgoingSpec |
| 99 | is HoverInteraction.Enter -> HoveredOutgoingSpec |
| 100 | is FocusInteraction.Focus -> DefaultOutgoingSpec |
| 101 | else -> null |
| 102 | } |
| 103 | } |
| 104 | } |
| 105 | |
| 106 | private val OutgoingSpecEasing: Easing = CubicBezierEasing(0.40f, 0.00f, 0.60f, 1.00f) |
| 107 | |
| 108 | private val DefaultIncomingSpec = TweenSpec<Dp>( |
| 109 | durationMillis = 120, |
| 110 | easing = FastOutSlowInEasing |
| 111 | ) |
| 112 | |
| 113 | private val DefaultOutgoingSpec = TweenSpec<Dp>( |
| 114 | durationMillis = 150, |
| 115 | easing = OutgoingSpecEasing |
| 116 | ) |
| 117 | |
| 118 | private val HoveredOutgoingSpec = TweenSpec<Dp>( |
| 119 | durationMillis = 120, |
| 120 | easing = OutgoingSpecEasing |
| 121 | ) |