| /* |
| * Copyright 2019 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.ui.layout |
| |
| import androidx.ui.core.IntPxSize |
| import androidx.ui.core.Layout |
| import androidx.ui.core.ipx |
| import androidx.ui.core.looseMin |
| import androidx.ui.core.max |
| import androidx.compose.Composable |
| import androidx.ui.core.Alignment |
| import androidx.ui.core.Constraints |
| import androidx.ui.core.DensityScope |
| import androidx.ui.core.IntPxPosition |
| import androidx.ui.core.LayoutModifier |
| |
| /** |
| * A layout that expects a child and places it within itself. The child will be measured |
| * with the same max constraints received by the parent, and 0 ipx min constraints. |
| * The parent will try to size itself to be as large as the child. If this is not possible |
| * (the child is too small and does not satisfy the min constraints of the parent), the parent |
| * will size itself to min constraints and the child will be aligned according to the alignment. |
| * |
| * For a composable that does alignment and tries to be as large as possible, see [Align]. |
| */ |
| @Composable |
| fun Wrap(alignment: Alignment = Alignment.TopLeft, children: @Composable() () -> Unit) { |
| Layout(children) { measurables, constraints -> |
| val measurable = measurables.firstOrNull() |
| // The child cannot be larger than our max constraints, but we ignore min constraints. |
| val placeable = measurable?.measure(constraints.looseMin()) |
| |
| // Try to be as small as possible. |
| val layoutWidth = max(placeable?.width ?: 0.ipx, constraints.minWidth) |
| val layoutHeight = max(placeable?.height ?: 0.ipx, constraints.minHeight) |
| |
| layout(layoutWidth, layoutHeight) { |
| if (placeable != null) { |
| val position = alignment.align( |
| IntPxSize(layoutWidth - placeable.width, layoutHeight - placeable.height) |
| ) |
| placeable.place(position.x, position.y) |
| } |
| } |
| } |
| } |
| |
| /** |
| * A layout modifier that tries to size itself to the size of the target component. |
| * To achieve this, the modifier measures the target layout with the max incoming constraints |
| * and zero min constraints, and then sizes itself to the measured size. If the measured size of |
| * the target layout is smaller than the incoming min constraints, the modified component will |
| * size itself to min incoming constraints and place its content in the center. |
| */ |
| val LayoutWrapped: LayoutModifier = object : LayoutModifier { |
| override fun DensityScope.modifyConstraints(constraints: Constraints) = constraints.looseMin() |
| |
| override fun DensityScope.modifySize( |
| constraints: Constraints, |
| childSize: IntPxSize |
| ): IntPxSize { |
| val width = max(childSize.width, constraints.minWidth) |
| val height = max(childSize.height, constraints.minHeight) |
| return IntPxSize(width, height) |
| } |
| |
| override fun DensityScope.modifyPosition( |
| childSize: IntPxSize, |
| containerSize: IntPxSize |
| ): IntPxPosition { |
| return Alignment.Center.align( |
| IntPxSize( |
| containerSize.width - childSize.width, |
| containerSize.height - childSize.height |
| ) |
| ) |
| } |
| } |