ModifiedLayoutNode.kt
/*
* 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.ui.node
import androidx.compose.ui.graphics.Canvas
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.graphics.Paint
import androidx.compose.ui.graphics.PaintingStyle
import androidx.compose.ui.layout.AlignmentLine
import androidx.compose.ui.layout.HorizontalAlignmentLine
import androidx.compose.ui.layout.LayoutCoordinates
import androidx.compose.ui.layout.LayoutModifier
import androidx.compose.ui.layout.Placeable
import androidx.compose.ui.unit.Constraints
internal class ModifiedLayoutNode(
wrapped: LayoutNodeWrapper,
modifier: LayoutModifier
) : DelegatingLayoutNodeWrapper<LayoutModifier>(wrapped, modifier) {
override fun measure(constraints: Constraints): Placeable = performingMeasure(constraints) {
with(modifier) {
measureResult = measureScope.measure(wrapped, constraints)
this@ModifiedLayoutNode
}
}
override fun minIntrinsicWidth(height: Int): Int =
with(modifier) {
measureScope.minIntrinsicWidth(wrapped, height)
}
override fun maxIntrinsicWidth(height: Int): Int =
with(modifier) {
measureScope.maxIntrinsicWidth(wrapped, height)
}
override fun minIntrinsicHeight(width: Int): Int =
with(modifier) {
measureScope.minIntrinsicHeight(wrapped, width)
}
override fun maxIntrinsicHeight(width: Int): Int =
with(modifier) {
measureScope.maxIntrinsicHeight(wrapped, width)
}
override fun calculateAlignmentLine(alignmentLine: AlignmentLine): Int {
if (measureResult.alignmentLines.containsKey(alignmentLine)) {
return measureResult.alignmentLines[alignmentLine] ?: AlignmentLine.Unspecified
}
val positionInWrapped = wrapped[alignmentLine]
if (positionInWrapped == AlignmentLine.Unspecified) {
return AlignmentLine.Unspecified
}
// Place our wrapped to obtain their position inside ourselves.
isShallowPlacing = true
placeAt(this.position, this.zIndex, this.layerBlock)
isShallowPlacing = false
return if (alignmentLine is HorizontalAlignmentLine) {
positionInWrapped + wrapped.position.y
} else {
positionInWrapped + wrapped.position.x
}
}
override fun performDraw(canvas: Canvas) {
wrapped.draw(canvas)
if (layoutNode.requireOwner().showLayoutBounds) {
drawBorder(canvas, modifierBoundsPaint)
}
}
override fun getWrappedByCoordinates(): LayoutCoordinates {
return this
}
internal companion object {
val modifierBoundsPaint = Paint().also { paint ->
paint.color = Color.Blue
paint.strokeWidth = 1f
paint.style = PaintingStyle.Stroke
}
}
}