| /* |
| * 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.ui.core |
| |
| import androidx.ui.core.LayoutNode.LayoutState |
| import androidx.ui.core.LayoutNode.MeasureBlocks |
| import androidx.ui.core.LayoutNode.UsageByParent |
| import androidx.ui.unit.IntOffset |
| import androidx.ui.unit.IntSize |
| |
| @OptIn(ExperimentalLayoutNodeApi::class) |
| internal class OuterMeasurablePlaceable( |
| private val layoutNode: LayoutNode, |
| var outerWrapper: LayoutNodeWrapper |
| ) : Measurable, Placeable() { |
| |
| private var measuredOnce = false |
| val lastConstraints: Constraints? get() = if (measuredOnce) measurementConstraints else null |
| var lastLayoutDirection: LayoutDirection? = null |
| private set |
| var lastPosition: IntOffset? = null |
| private set |
| private val lastProvidedAlignmentLines = mutableMapOf<AlignmentLine, Int>() |
| |
| /** |
| * A local version of [Owner.measureIteration] to ensure that [MeasureBlocks.measure] |
| * is not called multiple times within a measure pass. |
| */ |
| var measureIteration = -1L |
| private set |
| |
| override val parentData: Any? get() = outerWrapper.parentData |
| |
| /** |
| * The function to be executed when the parent layout measures its children. |
| */ |
| override fun measure(constraints: Constraints, layoutDirection: LayoutDirection): Placeable { |
| // when we measure the root it is like the virtual parent is currently laying out |
| val parentState = layoutNode.parent?.layoutState ?: LayoutState.LayingOut |
| layoutNode.measuredByParent = when (parentState) { |
| LayoutState.Measuring -> UsageByParent.InMeasureBlock |
| LayoutState.LayingOut -> UsageByParent.InLayoutBlock |
| else -> throw IllegalStateException( |
| "Measurable could be only measured from the parent's measure or layout block." + |
| "Parents state is $parentState" |
| ) |
| } |
| remeasure(constraints, layoutDirection) |
| return this |
| } |
| |
| /** |
| * Return true if the measured size has been changed |
| */ |
| fun remeasure(constraints: Constraints, layoutDirection: LayoutDirection): Boolean { |
| val owner = layoutNode.requireOwner() |
| val iteration = owner.measureIteration |
| val parent = layoutNode.parent |
| @Suppress("Deprecation") |
| layoutNode.canMultiMeasure = layoutNode.canMultiMeasure || |
| (parent != null && parent.canMultiMeasure) |
| @Suppress("Deprecation") |
| check(measureIteration != iteration || layoutNode.canMultiMeasure) { |
| "measure() may not be called multiple times on the same Measurable" |
| } |
| measureIteration = owner.measureIteration |
| if (layoutNode.layoutState == LayoutState.NeedsRemeasure || |
| measurementConstraints != constraints || |
| lastLayoutDirection != layoutDirection |
| ) { |
| measuredOnce = true |
| layoutNode.layoutState = LayoutState.Measuring |
| measurementConstraints = constraints |
| lastLayoutDirection = layoutDirection |
| lastProvidedAlignmentLines.clear() |
| lastProvidedAlignmentLines.putAll(layoutNode.providedAlignmentLines) |
| owner.observeMeasureModelReads(layoutNode) { |
| outerWrapper.measure(constraints, layoutDirection) |
| } |
| layoutNode.layoutState = LayoutState.NeedsRelayout |
| if (layoutNode.providedAlignmentLines != lastProvidedAlignmentLines) { |
| layoutNode.onAlignmentsChanged() |
| } |
| val previousSize = measuredSize |
| val newWidth = outerWrapper.width |
| val newHeight = outerWrapper.height |
| if (newWidth != previousSize.width || |
| newHeight != previousSize.height |
| ) { |
| measuredSize = IntSize(newWidth, newHeight) |
| return true |
| } |
| } |
| return false |
| } |
| |
| override fun get(line: AlignmentLine): Int = outerWrapper[line] |
| |
| override fun place(position: IntOffset) { |
| lastPosition = position |
| with(InnerPlacementScope) { |
| outerWrapper.placeAbsolute(position) |
| } |
| } |
| |
| /** |
| * Calls [place] with the same position used during the last [place] call |
| */ |
| fun replace() { |
| place(checkNotNull(lastPosition)) |
| } |
| |
| override fun minIntrinsicWidth(height: Int, layoutDirection: LayoutDirection): Int = |
| outerWrapper.minIntrinsicWidth(height, layoutDirection) |
| |
| override fun maxIntrinsicWidth(height: Int, layoutDirection: LayoutDirection): Int = |
| outerWrapper.maxIntrinsicWidth(height, layoutDirection) |
| |
| override fun minIntrinsicHeight(width: Int, layoutDirection: LayoutDirection): Int = |
| outerWrapper.minIntrinsicHeight(width, layoutDirection) |
| |
| override fun maxIntrinsicHeight(width: Int, layoutDirection: LayoutDirection): Int = |
| outerWrapper.maxIntrinsicHeight(width, layoutDirection) |
| } |