| /* |
| * 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.Constraints |
| import androidx.ui.core.Dp |
| import androidx.ui.core.IntPxSize |
| import androidx.ui.core.Layout |
| import androidx.ui.core.dp |
| import androidx.ui.core.enforce |
| import androidx.ui.core.ipx |
| import androidx.ui.core.isFinite |
| import androidx.ui.core.looseMin |
| import androidx.ui.core.max |
| import androidx.ui.core.offset |
| import androidx.ui.core.withTight |
| import androidx.compose.Composable |
| import androidx.compose.composer |
| import androidx.compose.trace |
| |
| /** |
| * A convenience widget that combines common layout widgets for one child: |
| * - padding: the padding to be applied to the child |
| * - alignment: how to position the padded child if the [Container] is larger than the child |
| * - constraints: additional Constraints to be enforced when measuring the Container |
| * - width: the width to be used for the Container |
| * - height: the height to be used for the Container |
| * |
| * When constraints, width and/or height are provided, these will be applied to the constraints |
| * incoming from the [Container]'s parent, and might not always be satisfied if this is impossible. |
| * |
| * By default, the [Container] will try to be the size of its child (including padding), or as |
| * small as possible within the incoming constraints if that is not possible. If expanded is |
| * [true], the [Container] will be as large as possible for bounded incoming constraints. |
| * If the padded child is smaller, regardless of the value of expanded, the provided alignment |
| * will be used to position it. For unbounded incoming constraints, the [Container] will wrap |
| * its child (same behavior as if expanded was [false]). Also, note that the measurement |
| * information passed for the [Container] (constraints, width and height) will not be satisfied |
| * if the incoming [Constraints] do not allow it. |
| */ |
| @Composable |
| fun Container( |
| padding: EdgeInsets = EdgeInsets(0.dp), |
| alignment: Alignment = Alignment.Center, |
| expanded: Boolean = false, |
| constraints: DpConstraints = DpConstraints(), |
| width: Dp? = null, |
| height: Dp? = null, |
| children: @Composable() () -> Unit |
| ) { |
| trace("UI:Container") { |
| Layout(children) { measurables, incomingConstraints -> |
| val containerConstraints = Constraints(constraints) |
| .withTight(width?.toIntPx(), height?.toIntPx()) |
| .enforce(incomingConstraints) |
| val totalHorizontal = padding.left.toIntPx() + padding.right.toIntPx() |
| val totalVertical = padding.top.toIntPx() + padding.bottom.toIntPx() |
| val childConstraints = containerConstraints |
| .looseMin() |
| .offset(-totalHorizontal, -totalVertical) |
| val placeable = measurables.firstOrNull()?.measure(childConstraints) |
| val containerWidth = if (!expanded || !containerConstraints.maxWidth.isFinite()) { |
| max((placeable?.width ?: 0.ipx) + totalHorizontal, containerConstraints.minWidth) |
| } else { |
| containerConstraints.maxWidth |
| } |
| val containerHeight = if (!expanded || !containerConstraints.maxHeight.isFinite()) { |
| max((placeable?.height ?: 0.ipx) + totalVertical, containerConstraints.minHeight) |
| } else { |
| containerConstraints.maxHeight |
| } |
| layout(containerWidth, containerHeight) { |
| if (placeable != null) { |
| val position = alignment.align( |
| IntPxSize( |
| containerWidth - placeable.width - totalHorizontal, |
| containerHeight - placeable.height - totalVertical |
| ) |
| ) |
| placeable.place( |
| padding.left.toIntPx() + position.x, |
| padding.top.toIntPx() + position.y |
| ) |
| } |
| } |
| } |
| } |
| } |
