| /* |
| * Copyright 2022 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.foundation.lazy.staggeredgrid |
| |
| import androidx.compose.animation.core.FiniteAnimationSpec |
| import androidx.compose.animation.core.Spring |
| import androidx.compose.animation.core.VisibilityThreshold |
| import androidx.compose.animation.core.spring |
| import androidx.compose.foundation.ExperimentalFoundationApi |
| import androidx.compose.foundation.lazy.layout.LazyLayoutAnimationSpecsNode |
| import androidx.compose.runtime.Stable |
| import androidx.compose.ui.Modifier |
| import androidx.compose.ui.node.ModifierNodeElement |
| import androidx.compose.ui.platform.InspectorInfo |
| import androidx.compose.ui.unit.IntOffset |
| |
| /** |
| * Receiver scope for itemContent in [LazyStaggeredGridScope.item] |
| */ |
| @Stable |
| @LazyStaggeredGridScopeMarker |
| sealed interface LazyStaggeredGridItemScope { |
| /** |
| * This modifier animates the item placement within the grid. |
| * |
| * When you scroll backward staggered grids could move already visible items in order |
| * to correct the accumulated errors in previous item size estimations. This modifier |
| * can animate such moves. |
| * |
| * Aside from that when you provide a key via [LazyStaggeredGridScope.item] / |
| * [LazyStaggeredGridScope.items] this modifier will enable item reordering animations. |
| * |
| * @param animationSpec a finite animation that will be used to animate the item placement. |
| */ |
| @ExperimentalFoundationApi |
| fun Modifier.animateItemPlacement( |
| animationSpec: FiniteAnimationSpec<IntOffset> = spring( |
| stiffness = Spring.StiffnessMediumLow, |
| visibilityThreshold = IntOffset.VisibilityThreshold |
| ) |
| ): Modifier |
| } |
| |
| @OptIn(ExperimentalFoundationApi::class) |
| internal object LazyStaggeredGridItemScopeImpl : LazyStaggeredGridItemScope { |
| @ExperimentalFoundationApi |
| override fun Modifier.animateItemPlacement(animationSpec: FiniteAnimationSpec<IntOffset>) = |
| this then AnimateItemElement(animationSpec) |
| } |
| |
| private data class AnimateItemElement( |
| val placementSpec: FiniteAnimationSpec<IntOffset> |
| ) : ModifierNodeElement<LazyLayoutAnimationSpecsNode>() { |
| |
| override fun create(): LazyLayoutAnimationSpecsNode = |
| LazyLayoutAnimationSpecsNode(null, placementSpec) |
| |
| override fun update(node: LazyLayoutAnimationSpecsNode) { |
| node.placementSpec = placementSpec |
| } |
| |
| override fun InspectorInfo.inspectableProperties() { |
| name = "animateItemPlacement" |
| value = placementSpec |
| } |
| } |