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599 行
23 KiB
599 行
23 KiB
using System;
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using System.Collections.Generic;
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using UIWidgets.gestures;
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using UIWidgets.painting;
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using UIWidgets.ui;
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namespace UIWidgets.rendering {
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public enum FlexFit {
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tight,
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loose,
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}
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public class FlexParentData : ContainerParentDataMixinBoxParentData<RenderBox> {
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public int flex;
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public FlexFit fit;
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}
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public enum MainAxisSize {
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min,
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max,
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}
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public enum MainAxisAlignment {
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start,
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end,
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center,
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spaceBetween,
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spaceAround,
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spaceEvenly,
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}
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public enum CrossAxisAlignment {
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start,
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end,
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center,
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stretch,
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baseline,
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}
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public delegate double _ChildSizingFunction(RenderBox child, double extent);
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public class RenderFlex : RenderBoxContainerDefaultsMixinContainerRenderObjectMixinRenderBox<RenderBox,
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FlexParentData> {
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public RenderFlex(
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List<RenderBox> children = null,
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Axis direction = Axis.horizontal,
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MainAxisSize mainAxisSize = MainAxisSize.max,
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MainAxisAlignment mainAxisAlignment = MainAxisAlignment.start,
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CrossAxisAlignment crossAxisAlignment = CrossAxisAlignment.center,
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TextDirection textDirection = TextDirection.ltr,
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VerticalDirection verticalDirection = VerticalDirection.down,
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TextBaseline textBaseline = TextBaseline.alphabetic
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) {
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this._direction = direction;
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this._mainAxisAlignment = mainAxisAlignment;
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this._mainAxisSize = mainAxisSize;
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this._crossAxisAlignment = crossAxisAlignment;
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this._textDirection = textDirection;
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this._verticalDirection = verticalDirection;
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this._textBaseline = textBaseline;
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this.addAll(children);
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}
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public Axis direction {
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get { return this._direction; }
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set {
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if (this._direction == value) {
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return;
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}
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this._direction = value;
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this.markNeedsLayout();
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}
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}
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public Axis _direction;
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public MainAxisSize mainAxisSize {
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get { return this._mainAxisSize; }
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set {
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if (this._mainAxisSize == value) {
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return;
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}
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this._mainAxisSize = value;
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this.markNeedsLayout();
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}
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}
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public MainAxisSize _mainAxisSize;
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public MainAxisAlignment mainAxisAlignment {
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get { return this._mainAxisAlignment; }
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set {
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if (this._mainAxisAlignment == value) {
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return;
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}
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this._mainAxisAlignment = value;
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this.markNeedsLayout();
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}
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}
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public MainAxisAlignment _mainAxisAlignment;
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public CrossAxisAlignment crossAxisAlignment {
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get { return this._crossAxisAlignment; }
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set {
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if (this._crossAxisAlignment == value) {
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return;
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}
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this._crossAxisAlignment = value;
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this.markNeedsLayout();
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}
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}
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public CrossAxisAlignment _crossAxisAlignment;
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public TextDirection textDirection {
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get { return this._textDirection; }
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set {
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if (this._textDirection == value) {
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return;
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}
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this._textDirection = value;
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this.markNeedsLayout();
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}
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}
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public TextDirection _textDirection;
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public VerticalDirection verticalDirection {
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get { return this._verticalDirection; }
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set {
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if (this._verticalDirection == value) {
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return;
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}
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this._verticalDirection = value;
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this.markNeedsLayout();
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}
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}
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public VerticalDirection _verticalDirection;
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public TextBaseline textBaseline {
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get { return this._textBaseline; }
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set {
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if (this._textBaseline == value) {
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return;
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}
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this._textBaseline = value;
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this.markNeedsLayout();
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}
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}
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public TextBaseline _textBaseline;
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public double _overflow;
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public override void setupParentData(RenderObject child) {
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if (!(child.parentData is FlexParentData)) {
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child.parentData = new FlexParentData();
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}
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}
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public double _getIntrinsicSize(
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Axis sizingDirection,
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double extent,
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_ChildSizingFunction childSize
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) {
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if (this._direction == sizingDirection) {
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double totalFlex = 0.0;
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double inflexibleSpace = 0.0;
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double maxFlexFractionSoFar = 0.0;
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RenderBox child = this.firstChild;
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while (child != null) {
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int flex = this._getFlex(child);
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totalFlex += flex;
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if (flex > 0) {
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double flexFraction = childSize(child, extent) / this._getFlex(child);
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maxFlexFractionSoFar = Math.Max(maxFlexFractionSoFar, flexFraction);
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} else {
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inflexibleSpace += childSize(child, extent);
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}
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var childParentData = (FlexParentData) child.parentData;
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child = childParentData.nextSibling;
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}
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return maxFlexFractionSoFar * totalFlex + inflexibleSpace;
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} else {
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double availableMainSpace = extent;
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int totalFlex = 0;
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double inflexibleSpace = 0.0;
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double maxCrossSize = 0.0;
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RenderBox child = this.firstChild;
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while (child != null) {
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int flex = this._getFlex(child);
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totalFlex += flex;
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if (flex == 0) {
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double mainSize = 0.0;
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double crossSize = 0.0;
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switch (this._direction) {
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case Axis.horizontal:
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mainSize = child.getMaxIntrinsicWidth(double.PositiveInfinity);
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crossSize = childSize(child, mainSize);
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break;
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case Axis.vertical:
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mainSize = child.getMaxIntrinsicHeight(double.PositiveInfinity);
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crossSize = childSize(child, mainSize);
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break;
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}
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inflexibleSpace += mainSize;
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maxCrossSize = Math.Max(maxCrossSize, crossSize);
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}
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var childParentData = (FlexParentData) child.parentData;
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child = childParentData.nextSibling;
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}
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double spacePerFlex = Math.Max(0.0, (availableMainSpace - inflexibleSpace) / totalFlex);
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child = this.firstChild;
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while (child != null) {
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int flex = this._getFlex(child);
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if (flex > 0) {
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maxCrossSize = Math.Max(maxCrossSize, childSize(child, spacePerFlex * flex));
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}
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var childParentData = (FlexParentData) child.parentData;
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child = childParentData.nextSibling;
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}
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return maxCrossSize;
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}
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}
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protected override double computeMinIntrinsicWidth(double height) {
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return this._getIntrinsicSize(
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sizingDirection: Axis.horizontal,
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extent: height,
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childSize: (RenderBox child, double extent) => child.getMinIntrinsicWidth(extent)
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);
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}
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protected override double computeMaxIntrinsicWidth(double height) {
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return this._getIntrinsicSize(
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sizingDirection: Axis.horizontal,
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extent: height,
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childSize: (RenderBox child, double extent) => child.getMaxIntrinsicWidth(extent)
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);
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}
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protected override double computeMinIntrinsicHeight(double width) {
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return this._getIntrinsicSize(
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sizingDirection: Axis.vertical,
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extent: width,
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childSize: (RenderBox child, double extent) => child.getMinIntrinsicHeight(extent)
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);
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}
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protected override double computeMaxIntrinsicHeight(double width) {
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return this._getIntrinsicSize(
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sizingDirection: Axis.vertical,
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extent: width,
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childSize: (RenderBox child, double extent) => child.getMaxIntrinsicHeight(extent)
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);
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}
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protected override double? computeDistanceToActualBaseline(TextBaseline baseline) {
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if (this._direction == Axis.horizontal) {
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return this.defaultComputeDistanceToHighestActualBaseline(baseline);
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}
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return this.defaultComputeDistanceToFirstActualBaseline(baseline);
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}
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public int _getFlex(RenderBox child) {
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var childParentData = (FlexParentData) child.parentData;
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return childParentData.flex;
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}
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public FlexFit _getFit(RenderBox child) {
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var childParentData = (FlexParentData) child.parentData;
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return childParentData.fit;
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}
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public double _getCrossSize(RenderBox child) {
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switch (this._direction) {
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case Axis.horizontal:
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return child.size.height;
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case Axis.vertical:
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return child.size.width;
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}
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return 0;
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}
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public double _getMainSize(RenderBox child) {
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switch (this._direction) {
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case Axis.horizontal:
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return child.size.width;
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case Axis.vertical:
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return child.size.height;
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}
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return 0;
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}
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protected override void performLayout() {
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int totalFlex = 0;
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int totalChildren = 0;
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double maxMainSize = this._direction == Axis.horizontal
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? this.constraints.maxWidth
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: this.constraints.maxHeight;
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bool canFlex = maxMainSize < double.PositiveInfinity;
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double crossSize = 0.0;
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double allocatedSize = 0.0;
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RenderBox child = this.firstChild;
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RenderBox lastFlexChild = null;
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while (child != null) {
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var childParentData = (FlexParentData) child.parentData;
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totalChildren++;
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int flex = this._getFlex(child);
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if (flex > 0) {
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totalFlex += childParentData.flex;
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lastFlexChild = child;
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} else {
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BoxConstraints innerConstraints = null;
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if (this.crossAxisAlignment == CrossAxisAlignment.stretch) {
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switch (this._direction) {
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case Axis.horizontal:
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innerConstraints = new BoxConstraints(
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minHeight: this.constraints.maxHeight,
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maxHeight: this.constraints.maxHeight);
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break;
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case Axis.vertical:
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innerConstraints = new BoxConstraints(
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minWidth: this.constraints.maxWidth,
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maxWidth: this.constraints.maxWidth);
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break;
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}
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} else {
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switch (this._direction) {
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case Axis.horizontal:
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innerConstraints = new BoxConstraints(
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maxHeight: this.constraints.maxHeight);
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break;
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case Axis.vertical:
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innerConstraints = new BoxConstraints(
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maxWidth: this.constraints.maxWidth);
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break;
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}
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}
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child.layout(innerConstraints, parentUsesSize: true);
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allocatedSize += this._getMainSize(child);
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crossSize = Math.Max(crossSize, this._getCrossSize(child));
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}
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child = childParentData.nextSibling;
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}
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double freeSpace = Math.Max(0.0, (canFlex ? maxMainSize : 0.0) - allocatedSize);
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double allocatedFlexSpace = 0.0;
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double maxBaselineDistance = 0.0;
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if (totalFlex > 0 || this.crossAxisAlignment == CrossAxisAlignment.baseline) {
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double spacePerFlex = canFlex && totalFlex > 0 ? (freeSpace / totalFlex) : double.NaN;
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child = this.firstChild;
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while (child != null) {
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int flex = this._getFlex(child);
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if (flex > 0) {
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double maxChildExtent = canFlex
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? (child == lastFlexChild ? (freeSpace - allocatedFlexSpace) : spacePerFlex * flex)
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: double.PositiveInfinity;
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double minChildExtent = 0.0;
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switch (this._getFit(child)) {
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case FlexFit.tight:
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minChildExtent = maxChildExtent;
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break;
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case FlexFit.loose:
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minChildExtent = 0.0;
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break;
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}
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BoxConstraints innerConstraints = null;
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if (this.crossAxisAlignment == CrossAxisAlignment.stretch) {
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switch (this._direction) {
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case Axis.horizontal:
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innerConstraints = new BoxConstraints(
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minWidth: minChildExtent,
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maxWidth: maxChildExtent,
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minHeight: this.constraints.maxHeight,
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maxHeight: this.constraints.maxHeight);
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break;
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case Axis.vertical:
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innerConstraints = new BoxConstraints(
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minWidth: this.constraints.maxWidth,
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maxWidth: this.constraints.maxWidth,
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minHeight: minChildExtent,
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maxHeight: maxChildExtent);
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break;
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}
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} else {
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switch (this._direction) {
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case Axis.horizontal:
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innerConstraints = new BoxConstraints(
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minWidth: minChildExtent,
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maxWidth: maxChildExtent,
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maxHeight: this.constraints.maxHeight);
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break;
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case Axis.vertical:
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innerConstraints = new BoxConstraints(
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maxWidth: this.constraints.maxWidth,
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minHeight: minChildExtent,
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maxHeight: maxChildExtent);
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break;
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}
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}
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child.layout(innerConstraints, parentUsesSize: true);
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double childSize = this._getMainSize(child);
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allocatedSize += childSize;
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allocatedFlexSpace += maxChildExtent;
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crossSize = Math.Max(crossSize, this._getCrossSize(child));
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}
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if (this.crossAxisAlignment == CrossAxisAlignment.baseline) {
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double? distance = child.getDistanceToBaseline(this.textBaseline, onlyReal: true);
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if (distance != null) {
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maxBaselineDistance = Math.Max(maxBaselineDistance, distance.Value);
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}
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}
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var childParentData = (FlexParentData) child.parentData;
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child = childParentData.nextSibling;
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}
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}
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double idealSize = canFlex && this.mainAxisSize == MainAxisSize.max ? maxMainSize : allocatedSize;
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double actualSize = 0.0;
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double actualSizeDelta = 0.0;
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switch (this._direction) {
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case Axis.horizontal:
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this.size = this.constraints.constrain(new Size(idealSize, crossSize));
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actualSize = this.size.width;
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crossSize = this.size.height;
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break;
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case Axis.vertical:
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this.size = this.constraints.constrain(new Size(crossSize, idealSize));
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actualSize = this.size.height;
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crossSize = this.size.width;
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break;
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}
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actualSizeDelta = actualSize - allocatedSize;
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this._overflow = Math.Max(0.0, -actualSizeDelta);
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double remainingSpace = Math.Max(0.0, actualSizeDelta);
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double leadingSpace = 0.0;
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double betweenSpace = 0.0;
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bool flipMainAxis = !RenderFlex._startIsTopLeft(this.direction, this.textDirection, this.verticalDirection);
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switch (this._mainAxisAlignment) {
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case MainAxisAlignment.start:
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leadingSpace = 0.0;
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betweenSpace = 0.0;
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break;
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case MainAxisAlignment.end:
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leadingSpace = remainingSpace;
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betweenSpace = 0.0;
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break;
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case MainAxisAlignment.center:
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leadingSpace = remainingSpace / 2.0;
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betweenSpace = 0.0;
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break;
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case MainAxisAlignment.spaceBetween:
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leadingSpace = 0.0;
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betweenSpace = totalChildren > 1 ? remainingSpace / (totalChildren - 1) : 0.0;
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break;
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case MainAxisAlignment.spaceAround:
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betweenSpace = totalChildren > 0 ? remainingSpace / totalChildren : 0.0;
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leadingSpace = betweenSpace / 2.0;
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break;
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case MainAxisAlignment.spaceEvenly:
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betweenSpace = totalChildren > 0 ? remainingSpace / (totalChildren + 1) : 0.0;
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leadingSpace = betweenSpace;
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break;
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}
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// Position elements
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double childMainPosition = flipMainAxis ? actualSize - leadingSpace : leadingSpace;
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child = this.firstChild;
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while (child != null) {
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var childParentData = (FlexParentData) child.parentData;
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double childCrossPosition = 0.0;
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switch (this._crossAxisAlignment) {
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case CrossAxisAlignment.start:
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case CrossAxisAlignment.end:
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childCrossPosition =
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RenderFlex._startIsTopLeft(
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AxisUtils.flipAxis(this.direction), this.textDirection, this.verticalDirection)
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== (this._crossAxisAlignment == CrossAxisAlignment.start)
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? 0.0
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: crossSize - this._getCrossSize(child);
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break;
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case CrossAxisAlignment.center:
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childCrossPosition = crossSize / 2.0 - this._getCrossSize(child) / 2.0;
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break;
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case CrossAxisAlignment.stretch:
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childCrossPosition = 0.0;
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break;
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case CrossAxisAlignment.baseline:
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childCrossPosition = 0.0;
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if (this._direction == Axis.horizontal) {
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double? distance = child.getDistanceToBaseline(this.textBaseline, onlyReal: true);
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if (distance != null) {
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childCrossPosition = maxBaselineDistance - distance.Value;
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}
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}
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break;
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}
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if (flipMainAxis) {
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childMainPosition -= this._getMainSize(child);
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}
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switch (this._direction) {
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case Axis.horizontal:
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childParentData.offset = new Offset(childMainPosition, childCrossPosition);
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break;
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case Axis.vertical:
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childParentData.offset = new Offset(childCrossPosition, childMainPosition);
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break;
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}
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if (flipMainAxis) {
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childMainPosition -= betweenSpace;
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} else {
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childMainPosition += this._getMainSize(child) + betweenSpace;
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}
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child = childParentData.nextSibling;
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}
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}
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private static bool _startIsTopLeft(Axis direction, TextDirection textDirection,
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VerticalDirection verticalDirection) {
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switch (direction) {
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case Axis.horizontal:
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switch (textDirection) {
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case TextDirection.ltr:
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return true;
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case TextDirection.rtl:
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return false;
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}
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break;
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case Axis.vertical:
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switch (verticalDirection) {
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case VerticalDirection.down:
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return true;
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case VerticalDirection.up:
|
|
return false;
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
public override void paint(PaintingContext context, Offset offset) {
|
|
if (this._overflow <= 0.0) {
|
|
this.defaultPaint(context, offset);
|
|
return;
|
|
}
|
|
|
|
if (this.size.isEmpty)
|
|
return;
|
|
|
|
context.pushClipRect(this.needsCompositing, offset, Offset.zero & this.size, this.defaultPaint);
|
|
}
|
|
|
|
protected override bool hitTestChildren(HitTestResult result, Offset position = null) {
|
|
return defaultHitTestChildren(result, position: position);
|
|
}
|
|
}
|
|
}
|