| /* |
| * Copyright 2020 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package androidx.compose.animation |
| |
| import androidx.compose.animation.core.AnimationClockObservable |
| import androidx.compose.animation.core.AnimationSpec |
| import androidx.compose.animation.core.AnimationVector2D |
| import androidx.compose.animation.core.SpringSpec |
| import androidx.compose.animation.core.spring |
| import androidx.compose.remember |
| import androidx.ui.core.AnimationClockAmbient |
| import androidx.ui.core.Constraints |
| import androidx.ui.core.LayoutDirection |
| import androidx.ui.core.LayoutModifier |
| import androidx.ui.core.Measurable |
| import androidx.ui.core.MeasureScope |
| import androidx.ui.core.Modifier |
| import androidx.ui.core.clipToBounds |
| import androidx.ui.core.composed |
| import androidx.ui.unit.IntSize |
| |
| /** |
| * This modifier animates its own size when its child modifier (or the child composable if it |
| * is already at the tail of the chain) changes size. This allows the parent modifier to observe |
| * a smooth size change, resulting in an overall continuous visual change. |
| * |
| * An [AnimationSpec] can be optionally specified for the size change animation. By default, |
| * [SpringSpec] will be used. Clipping defaults to true, such that the content outside of animated |
| * size will not be shown. |
| * |
| * @sample androidx.compose.animation.samples.AnimateContent |
| * |
| * @param animSpec the animation that will be used to animate size change |
| * @param clip whether content outside of animated size should be clipped |
| */ |
| fun Modifier.animateContentSize( |
| animSpec: AnimationSpec<IntSize> = spring(), |
| clip: Boolean = true |
| ): Modifier = composed { |
| val clock = AnimationClockAmbient.current.asDisposableClock() |
| val animModifier = remember { |
| SizeAnimationModifier(animSpec, clock) |
| } |
| if (clip) { |
| this + Modifier.clipToBounds() + animModifier |
| } else { |
| this + animModifier |
| } |
| } |
| |
| /** |
| * This class creates a [LayoutModifier] that measures children, and responds to children's size |
| * change by animating to that size. The size reported to parents will be the animated size. |
| */ |
| private class SizeAnimationModifier( |
| val animSpec: AnimationSpec<IntSize>, |
| val clock: AnimationClockObservable |
| ) : LayoutModifier { |
| var sizeAnim: AnimatedValueModel<IntSize, AnimationVector2D>? = null |
| |
| override fun MeasureScope.measure( |
| measurable: Measurable, |
| constraints: Constraints, |
| layoutDirection: LayoutDirection |
| ): MeasureScope.MeasureResult { |
| |
| val placeable = measurable.measure(constraints) |
| |
| val measuredSize = IntSize(placeable.width, placeable.height) |
| |
| val anim = sizeAnim?.apply { |
| if (targetValue != measuredSize) { |
| animateTo(measuredSize, animSpec) |
| } |
| } ?: AnimatedValueModel( |
| measuredSize, IntSizeToVectorConverter, clock, IntSize(1, 1) |
| ) |
| sizeAnim = anim |
| return layout(anim.value.width, anim.value.height) { |
| placeable.place(0, 0) |
| } |
| } |
| } |