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1397 行
56 KiB
1397 行
56 KiB
using System;
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using System.Collections.Generic;
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using Unity.UIWidgets.animation;
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using Unity.UIWidgets.foundation;
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using Unity.UIWidgets.gestures;
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using Unity.UIWidgets.painting;
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using Unity.UIWidgets.ui;
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namespace Unity.UIWidgets.rendering {
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public interface RenderAbstractViewport {
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RevealedOffset getOffsetToReveal(RenderObject target, double alignment, Rect rect = null);
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RenderObject parent { get; }
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}
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public static class RenderViewportUtils {
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public static RenderAbstractViewport of(RenderObject obj) {
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while (obj != null) {
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if (obj is RenderAbstractViewport) {
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return (RenderAbstractViewport) obj;
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}
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obj = (RenderObject) obj.parent;
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}
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return null;
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}
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public const double defaultCacheExtent = 250.0;
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}
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public class RevealedOffset {
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public RevealedOffset(
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double offset,
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Rect rect) {
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D.assert(rect != null);
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this.offset = offset;
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this.rect = rect;
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}
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public readonly double offset;
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public readonly Rect rect;
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public override string ToString() {
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return $"{this.GetType()}(offset: {this.offset}, rect: {this.rect})";
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}
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}
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public abstract class RenderViewportBase<ParentDataClass> :
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ContainerRenderObjectMixinRenderBox<RenderSliver, ParentDataClass>,
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RenderAbstractViewport
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where ParentDataClass : ParentData, ContainerParentDataMixin<RenderSliver> {
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protected RenderViewportBase(
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AxisDirection axisDirection = AxisDirection.down,
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AxisDirection crossAxisDirection = AxisDirection.right,
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ViewportOffset offset = null,
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double cacheExtent = RenderViewportUtils.defaultCacheExtent
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) {
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D.assert(offset != null);
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D.assert(AxisUtils.axisDirectionToAxis(axisDirection) != AxisUtils.axisDirectionToAxis(crossAxisDirection));
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this._axisDirection = axisDirection;
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this._crossAxisDirection = crossAxisDirection;
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this._offset = offset;
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this._cacheExtent = cacheExtent;
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}
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public new RenderObject parent {
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get { return (RenderObject) base.parent; }
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}
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public AxisDirection axisDirection {
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get { return this._axisDirection; }
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set {
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if (value == this._axisDirection) {
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return;
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}
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this._axisDirection = value;
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this.markNeedsLayout();
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}
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}
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AxisDirection _axisDirection;
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public AxisDirection crossAxisDirection {
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get { return this._crossAxisDirection; }
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set {
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if (value == this._crossAxisDirection) {
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return;
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}
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this._crossAxisDirection = value;
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this.markNeedsLayout();
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}
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}
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AxisDirection _crossAxisDirection;
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public Axis axis {
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get { return AxisUtils.axisDirectionToAxis(this.axisDirection); }
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}
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public ViewportOffset offset {
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get { return this._offset; }
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set {
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D.assert(value != null);
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if (value == this._offset) {
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return;
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}
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if (this.attached) {
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this._offset.removeListener(this.markNeedsLayout);
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}
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this._offset = value;
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if (this.attached) {
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this._offset.addListener(this.markNeedsLayout);
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}
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this.markNeedsLayout();
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}
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}
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ViewportOffset _offset;
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public double cacheExtent {
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get { return this._cacheExtent; }
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set {
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if (value == this._cacheExtent) {
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return;
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}
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this._cacheExtent = value;
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this.markNeedsLayout();
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}
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}
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double _cacheExtent;
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public override void attach(object owner) {
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base.attach(owner);
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this._offset.addListener(this.markNeedsLayout);
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}
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public override void detach() {
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this._offset.removeListener(this.markNeedsLayout);
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base.detach();
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}
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protected virtual bool debugThrowIfNotCheckingIntrinsics() {
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D.assert(() => {
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if (!debugCheckingIntrinsics) {
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D.assert(!(this is RenderShrinkWrappingViewport));
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throw new UIWidgetsError(
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this.GetType() + " does not support returning intrinsic dimensions.\n" +
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"Calculating the intrinsic dimensions would require instantiating every child of " +
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"the viewport, which defeats the point of viewports being lazy.\n" +
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"If you are merely trying to shrink-wrap the viewport in the main axis direction, " +
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"consider a RenderShrinkWrappingViewport render object (ShrinkWrappingViewport widget), " +
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"which achieves that effect without implementing the intrinsic dimension API."
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);
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}
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return true;
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});
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return true;
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}
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protected override double computeMinIntrinsicWidth(double height) {
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D.assert(this.debugThrowIfNotCheckingIntrinsics());
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return 0.0;
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}
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protected override double computeMaxIntrinsicWidth(double height) {
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D.assert(this.debugThrowIfNotCheckingIntrinsics());
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return 0.0;
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}
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protected override double computeMinIntrinsicHeight(double width) {
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D.assert(this.debugThrowIfNotCheckingIntrinsics());
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return 0.0;
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}
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protected override double computeMaxIntrinsicHeight(double width) {
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D.assert(this.debugThrowIfNotCheckingIntrinsics());
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return 0.0;
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}
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public override bool isRepaintBoundary {
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get { return true; }
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}
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protected double layoutChildSequence(
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RenderSliver child,
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double scrollOffset,
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double overlap,
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double layoutOffset,
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double remainingPaintExtent,
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double mainAxisExtent,
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double crossAxisExtent,
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GrowthDirection growthDirection,
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Func<RenderSliver, RenderSliver> advance,
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double remainingCacheExtent,
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double cacheOrigin
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) {
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D.assert(scrollOffset.isFinite());
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D.assert(scrollOffset >= 0.0);
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double initialLayoutOffset = layoutOffset;
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ScrollDirection adjustedUserScrollDirection =
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GrowthDirectionUtils.applyGrowthDirectionToScrollDirection(
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this.offset.userScrollDirection, growthDirection);
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double maxPaintOffset = layoutOffset + overlap;
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while (child != null) {
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double sliverScrollOffset = scrollOffset <= 0.0 ? 0.0 : scrollOffset;
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double correctedCacheOrigin = Math.Max(cacheOrigin, -sliverScrollOffset);
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double cacheExtentCorrection = cacheOrigin - correctedCacheOrigin;
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D.assert(sliverScrollOffset >= correctedCacheOrigin.abs());
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D.assert(correctedCacheOrigin <= 0.0);
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D.assert(sliverScrollOffset >= 0.0);
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D.assert(cacheExtentCorrection <= 0.0);
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child.layout(new SliverConstraints(
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axisDirection: this.axisDirection,
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growthDirection: growthDirection,
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userScrollDirection: adjustedUserScrollDirection,
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scrollOffset: sliverScrollOffset,
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overlap: maxPaintOffset - layoutOffset,
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remainingPaintExtent: Math.Max(0.0, remainingPaintExtent - layoutOffset + initialLayoutOffset),
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crossAxisExtent: crossAxisExtent,
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crossAxisDirection: this.crossAxisDirection,
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viewportMainAxisExtent: mainAxisExtent,
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remainingCacheExtent: Math.Max(0.0, remainingCacheExtent + cacheExtentCorrection),
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cacheOrigin: correctedCacheOrigin
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), parentUsesSize: true);
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var childLayoutGeometry = child.geometry;
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D.assert(childLayoutGeometry.debugAssertIsValid());
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if (childLayoutGeometry.scrollOffsetCorrection != null) {
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return childLayoutGeometry.scrollOffsetCorrection.Value;
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}
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double effectiveLayoutOffset = layoutOffset + childLayoutGeometry.paintOrigin;
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if (childLayoutGeometry.visible || scrollOffset > 0) {
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this.updateChildLayoutOffset(child, effectiveLayoutOffset, growthDirection);
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}
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else {
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this.updateChildLayoutOffset(child, -scrollOffset + initialLayoutOffset, growthDirection);
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}
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maxPaintOffset = Math.Max(effectiveLayoutOffset + childLayoutGeometry.paintExtent, maxPaintOffset);
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scrollOffset -= childLayoutGeometry.scrollExtent;
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layoutOffset += childLayoutGeometry.layoutExtent;
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if (childLayoutGeometry.cacheExtent != 0.0) {
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remainingCacheExtent -= childLayoutGeometry.cacheExtent - cacheExtentCorrection;
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cacheOrigin = Math.Min(correctedCacheOrigin + childLayoutGeometry.cacheExtent, 0.0);
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}
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this.updateOutOfBandData(growthDirection, childLayoutGeometry);
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child = advance(child);
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}
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return 0.0;
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}
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public override Rect describeApproximatePaintClip(RenderObject childRaw) {
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RenderSliver child = (RenderSliver) childRaw;
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Rect viewportClip = Offset.zero & this.size;
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if (child.constraints.overlap == 0.0) {
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return viewportClip;
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}
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double left = viewportClip.left;
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double right = viewportClip.right;
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double top = viewportClip.top;
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double bottom = viewportClip.bottom;
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double startOfOverlap = child.constraints.viewportMainAxisExtent - child.constraints.remainingPaintExtent;
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double overlapCorrection = startOfOverlap + child.constraints.overlap;
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switch (GrowthDirectionUtils.applyGrowthDirectionToAxisDirection(
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this.axisDirection, child.constraints.growthDirection)) {
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case AxisDirection.down:
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top += overlapCorrection;
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break;
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case AxisDirection.up:
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bottom -= overlapCorrection;
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break;
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case AxisDirection.right:
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left += overlapCorrection;
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break;
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case AxisDirection.left:
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right -= overlapCorrection;
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break;
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}
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return Rect.fromLTRB(left, top, right, bottom);
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}
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public override void paint(PaintingContext context, Offset offset) {
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if (this.firstChild == null) {
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return;
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}
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if (this.hasVisualOverflow) {
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context.pushClipRect(this.needsCompositing, offset, Offset.zero & this.size, this._paintContents);
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}
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else {
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this._paintContents(context, offset);
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}
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}
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public void _paintContents(PaintingContext context, Offset offset) {
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foreach (RenderSliver child in this.childrenInPaintOrder) {
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if (child.geometry.visible) {
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context.paintChild(child, offset + this.paintOffsetOf(child));
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}
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}
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}
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protected override void debugPaintSize(PaintingContext context, Offset offset) {
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D.assert(() => {
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base.debugPaintSize(context, offset);
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Paint paint = new Paint {
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color = new Color(0xFF00FF00)
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};
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Canvas canvas = context.canvas;
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RenderSliver child = this.firstChild;
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while (child != null) {
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Size size = null;
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switch (this.axis) {
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case Axis.vertical:
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size = new Size(child.constraints.crossAxisExtent, child.geometry.layoutExtent);
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break;
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case Axis.horizontal:
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size = new Size(child.geometry.layoutExtent, child.constraints.crossAxisExtent);
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break;
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}
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D.assert(size != null);
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// canvas.drawRect(((offset + this.paintOffsetOf(child)) & size).deflate(0.5),
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// BorderWidth.all(1), BorderRadius.zero, paint);
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child = this.childAfter(child);
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}
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return true;
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});
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}
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protected override bool hitTestChildren(HitTestResult result, Offset position = null) {
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D.assert(position != null);
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double mainAxisPosition = 0, crossAxisPosition = 0;
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switch (this.axis) {
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case Axis.vertical:
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mainAxisPosition = position.dy;
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crossAxisPosition = position.dx;
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break;
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case Axis.horizontal:
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mainAxisPosition = position.dx;
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crossAxisPosition = position.dy;
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break;
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}
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foreach (RenderSliver child in this.childrenInHitTestOrder) {
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if (child.geometry.visible && child.hitTest(
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result,
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mainAxisPosition: this.computeChildMainAxisPosition(child, mainAxisPosition),
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crossAxisPosition: crossAxisPosition
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)) {
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return true;
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}
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}
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return false;
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}
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public RevealedOffset getOffsetToReveal(RenderObject target, double alignment, Rect rect = null) {
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double leadingScrollOffset = 0.0;
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double targetMainAxisExtent = 0.0;
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RenderObject descendant;
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rect = rect ?? target.paintBounds;
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Matrix3 transform;
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if (target is RenderBox) {
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RenderBox targetBox = (RenderBox) target;
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RenderBox pivot = targetBox;
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while (pivot.parent is RenderBox) {
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pivot = (RenderBox) pivot.parent;
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}
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D.assert(pivot.parent != null);
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D.assert(pivot.parent != this);
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D.assert(pivot != this);
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D.assert(pivot.parent is RenderSliver);
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RenderSliver pivotParent = (RenderSliver) pivot.parent;
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transform = targetBox.getTransformTo(pivot);
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Rect bounds = transform.mapRect(rect);
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double offset = 0.0;
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GrowthDirection growthDirection = pivotParent.constraints.growthDirection;
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switch (GrowthDirectionUtils.applyGrowthDirectionToAxisDirection(this.axisDirection, growthDirection)) {
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case AxisDirection.up:
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switch (growthDirection) {
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case GrowthDirection.forward:
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offset = bounds.bottom;
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break;
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case GrowthDirection.reverse:
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offset = bounds.top;
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break;
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}
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leadingScrollOffset = pivot.size.height - offset;
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targetMainAxisExtent = bounds.height;
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break;
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case AxisDirection.right:
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leadingScrollOffset = bounds.left;
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targetMainAxisExtent = bounds.width;
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break;
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case AxisDirection.down:
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leadingScrollOffset = bounds.top;
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targetMainAxisExtent = bounds.height;
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break;
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case AxisDirection.left:
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switch (growthDirection) {
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case GrowthDirection.forward:
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offset = bounds.right;
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break;
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case GrowthDirection.reverse:
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offset = bounds.left;
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break;
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}
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leadingScrollOffset = pivot.size.width - offset;
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targetMainAxisExtent = bounds.width;
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break;
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}
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descendant = pivot;
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}
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else if (target is RenderSliver) {
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RenderSliver targetSliver = (RenderSliver) target;
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leadingScrollOffset = 0.0;
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targetMainAxisExtent = targetSliver.geometry.scrollExtent;
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descendant = targetSliver;
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}
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else {
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return new RevealedOffset(offset: this.offset.pixels, rect: rect);
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}
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RenderObject child = descendant;
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while (child.parent is RenderSliver) {
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var parent = (RenderSliver) child.parent;
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leadingScrollOffset += parent.childScrollOffset(child);
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child = parent;
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}
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D.assert(child.parent == this);
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D.assert(child is RenderSliver);
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RenderSliver sliver = (RenderSliver) child;
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double extentOfPinnedSlivers = this.maxScrollObstructionExtentBefore(sliver);
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leadingScrollOffset = this.scrollOffsetOf(sliver, leadingScrollOffset);
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switch (sliver.constraints.growthDirection) {
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case GrowthDirection.forward:
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leadingScrollOffset -= extentOfPinnedSlivers;
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break;
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case GrowthDirection.reverse:
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break;
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}
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double mainAxisExtent = 0.0;
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switch (this.axis) {
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case Axis.horizontal:
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mainAxisExtent = this.size.width - extentOfPinnedSlivers;
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break;
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case Axis.vertical:
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mainAxisExtent = this.size.height - extentOfPinnedSlivers;
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break;
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}
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double targetOffset = leadingScrollOffset - (mainAxisExtent - targetMainAxisExtent) * alignment;
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double offsetDifference = this.offset.pixels - targetOffset;
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transform = target.getTransformTo(this);
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this.applyPaintTransform(child, transform);
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Rect targetRect = transform.mapRect(rect);
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switch (this.axisDirection) {
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case AxisDirection.down:
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targetRect = targetRect.translate(0.0, offsetDifference);
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break;
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case AxisDirection.right:
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targetRect = targetRect.translate(offsetDifference, 0.0);
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break;
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case AxisDirection.up:
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targetRect = targetRect.translate(0.0, -offsetDifference);
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break;
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case AxisDirection.left:
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targetRect = targetRect.translate(-offsetDifference, 0.0);
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break;
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}
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return new RevealedOffset(offset: targetOffset, rect: targetRect);
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}
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protected Offset computeAbsolutePaintOffset(RenderSliver child, double layoutOffset,
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GrowthDirection growthDirection) {
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D.assert(this.hasSize);
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D.assert(child != null);
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D.assert(child.geometry != null);
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switch (GrowthDirectionUtils.applyGrowthDirectionToAxisDirection(this.axisDirection, growthDirection)) {
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case AxisDirection.up:
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return new Offset(0.0, this.size.height - (layoutOffset + child.geometry.paintExtent));
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case AxisDirection.right:
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return new Offset(layoutOffset, 0.0);
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case AxisDirection.down:
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return new Offset(0.0, layoutOffset);
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case AxisDirection.left:
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return new Offset(this.size.width - (layoutOffset + child.geometry.paintExtent), 0.0);
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}
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return null;
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}
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public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
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base.debugFillProperties(properties);
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properties.add(new EnumProperty<AxisDirection>("axisDirection", this.axisDirection));
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properties.add(new EnumProperty<AxisDirection>("crossAxisDirection", this.crossAxisDirection));
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properties.add(new DiagnosticsProperty<ViewportOffset>("offset", this.offset));
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}
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public override List<DiagnosticsNode> debugDescribeChildren() {
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var children = new List<DiagnosticsNode>();
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RenderSliver child = this.firstChild;
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if (child == null) {
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return children;
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}
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int count = this.indexOfFirstChild;
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while (true) {
|
|
children.Add(child.toDiagnosticsNode(name: this.labelForChild(count)));
|
|
if (child == this.lastChild) {
|
|
break;
|
|
}
|
|
|
|
count += 1;
|
|
child = this.childAfter(child);
|
|
}
|
|
|
|
return children;
|
|
}
|
|
|
|
|
|
protected abstract bool hasVisualOverflow { get; }
|
|
|
|
protected abstract void
|
|
updateOutOfBandData(GrowthDirection growthDirection, SliverGeometry childLayoutGeometry);
|
|
|
|
protected abstract void updateChildLayoutOffset(RenderSliver child, double layoutOffset,
|
|
GrowthDirection growthDirection);
|
|
|
|
protected abstract Offset paintOffsetOf(RenderSliver child);
|
|
|
|
protected abstract double scrollOffsetOf(RenderSliver child, double scrollOffsetWithinChild);
|
|
|
|
protected abstract double maxScrollObstructionExtentBefore(RenderSliver child);
|
|
|
|
protected abstract double computeChildMainAxisPosition(RenderSliver child, double parentMainAxisPosition);
|
|
|
|
protected abstract int indexOfFirstChild { get; }
|
|
|
|
protected abstract string labelForChild(int index);
|
|
|
|
protected abstract IEnumerable<RenderSliver> childrenInPaintOrder { get; }
|
|
|
|
protected abstract IEnumerable<RenderSliver> childrenInHitTestOrder { get; }
|
|
|
|
public override void showOnScreen(
|
|
RenderObject descendant,
|
|
Rect rect,
|
|
TimeSpan? duration = null,
|
|
Curve curve = null
|
|
) {
|
|
duration = duration ?? TimeSpan.Zero;
|
|
curve = curve ?? Curves.ease;
|
|
|
|
if (!this.offset.allowImplicitScrolling) {
|
|
base.showOnScreen(
|
|
descendant: descendant,
|
|
rect: rect,
|
|
duration: duration,
|
|
curve: curve
|
|
);
|
|
return;
|
|
}
|
|
|
|
Rect newRect = showInViewport(
|
|
descendant: descendant,
|
|
viewport: this,
|
|
offset: this.offset,
|
|
rect: rect,
|
|
duration: duration,
|
|
curve: curve
|
|
);
|
|
base.showOnScreen(
|
|
rect: newRect,
|
|
duration: duration,
|
|
curve: curve
|
|
);
|
|
}
|
|
|
|
public static Rect showInViewport(
|
|
RenderObject descendant = null,
|
|
Rect rect = null,
|
|
RenderAbstractViewport viewport = null,
|
|
ViewportOffset offset = null,
|
|
TimeSpan? duration = null,
|
|
Curve curve = null
|
|
) {
|
|
duration = duration ?? TimeSpan.Zero;
|
|
curve = curve ?? Curves.ease;
|
|
D.assert(viewport != null);
|
|
D.assert(offset != null);
|
|
if (descendant == null) {
|
|
return rect;
|
|
}
|
|
|
|
RevealedOffset leadingEdgeOffset = viewport.getOffsetToReveal(descendant, 0.0, rect: rect);
|
|
RevealedOffset trailingEdgeOffset = viewport.getOffsetToReveal(descendant, 1.0, rect: rect);
|
|
double currentOffset = offset.pixels;
|
|
|
|
|
|
RevealedOffset targetOffset = null;
|
|
if (leadingEdgeOffset.offset < trailingEdgeOffset.offset) {
|
|
double leadingEdgeDiff = (offset.pixels - leadingEdgeOffset.offset).abs();
|
|
double trailingEdgeDiff = (offset.pixels - trailingEdgeOffset.offset).abs();
|
|
targetOffset = leadingEdgeDiff < trailingEdgeDiff ? leadingEdgeOffset : trailingEdgeOffset;
|
|
}
|
|
else if (currentOffset > leadingEdgeOffset.offset) {
|
|
targetOffset = leadingEdgeOffset;
|
|
}
|
|
else if (currentOffset < trailingEdgeOffset.offset) {
|
|
targetOffset = trailingEdgeOffset;
|
|
}
|
|
else {
|
|
var transform = descendant.getTransformTo(viewport.parent);
|
|
return transform.mapRect(rect ?? descendant.paintBounds);
|
|
}
|
|
|
|
D.assert(targetOffset != null);
|
|
|
|
if (duration == TimeSpan.Zero) {
|
|
offset.jumpTo(targetOffset.offset);
|
|
}
|
|
else {
|
|
offset.animateTo(targetOffset.offset, duration: duration.Value, curve: curve);
|
|
}
|
|
|
|
return targetOffset.rect;
|
|
}
|
|
}
|
|
|
|
|
|
public class RenderViewport : RenderViewportBase<SliverPhysicalContainerParentData> {
|
|
public RenderViewport(
|
|
AxisDirection axisDirection = AxisDirection.down,
|
|
AxisDirection crossAxisDirection = AxisDirection.right,
|
|
ViewportOffset offset = null,
|
|
double anchor = 0.0,
|
|
List<RenderSliver> children = null,
|
|
RenderSliver center = null,
|
|
double cacheExtent = RenderViewportUtils.defaultCacheExtent
|
|
) : base(axisDirection, crossAxisDirection, offset, cacheExtent) {
|
|
D.assert(anchor >= 0.0 && anchor <= 1.0);
|
|
this._anchor = anchor;
|
|
this._center = center;
|
|
|
|
this.addAll(children);
|
|
|
|
if (center == null && this.firstChild != null) {
|
|
this._center = this.firstChild;
|
|
}
|
|
}
|
|
|
|
public override void setupParentData(RenderObject child) {
|
|
if (!(child.parentData is SliverPhysicalContainerParentData)) {
|
|
child.parentData = new SliverPhysicalContainerParentData();
|
|
}
|
|
}
|
|
|
|
public double anchor {
|
|
get { return this._anchor; }
|
|
set {
|
|
D.assert(value >= 0.0 && value <= 1.0);
|
|
|
|
if (value == this._anchor) {
|
|
return;
|
|
}
|
|
|
|
this._anchor = value;
|
|
this.markNeedsLayout();
|
|
}
|
|
}
|
|
|
|
public double _anchor;
|
|
|
|
public RenderSliver center {
|
|
get { return this._center; }
|
|
set {
|
|
if (value == this._center) {
|
|
return;
|
|
}
|
|
|
|
this._center = value;
|
|
this.markNeedsLayout();
|
|
}
|
|
}
|
|
|
|
public RenderSliver _center;
|
|
|
|
protected override bool sizedByParent {
|
|
get { return true; }
|
|
}
|
|
|
|
protected override void performResize() {
|
|
D.assert(() => {
|
|
if (!this.constraints.hasBoundedHeight || !this.constraints.hasBoundedWidth) {
|
|
switch (this.axis) {
|
|
case Axis.vertical:
|
|
if (!this.constraints.hasBoundedHeight) {
|
|
throw new UIWidgetsError(
|
|
"Vertical viewport was given unbounded height.\n" +
|
|
"Viewports expand in the scrolling direction to fill their container." +
|
|
"In this case, a vertical viewport was given an unlimited amount of " +
|
|
"vertical space in which to expand. This situation typically happens " +
|
|
"when a scrollable widget is nested inside another scrollable widget.\n" +
|
|
"If this widget is always nested in a scrollable widget there " +
|
|
"is no need to use a viewport because there will always be enough " +
|
|
"vertical space for the children. In this case, consider using a " +
|
|
"Column instead. Otherwise, consider using the \"shrinkWrap\" property " +
|
|
"(or a ShrinkWrappingViewport) to size the height of the viewport " +
|
|
"to the sum of the heights of its children."
|
|
);
|
|
}
|
|
|
|
if (!this.constraints.hasBoundedWidth) {
|
|
throw new UIWidgetsError(
|
|
"Vertical viewport was given unbounded width.\n" +
|
|
"Viewports expand in the cross axis to fill their container and " +
|
|
"constrain their children to match their extent in the cross axis. " +
|
|
"In this case, a vertical viewport was given an unlimited amount of " +
|
|
"horizontal space in which to expand."
|
|
);
|
|
}
|
|
|
|
break;
|
|
case Axis.horizontal:
|
|
if (!this.constraints.hasBoundedWidth) {
|
|
throw new UIWidgetsError(
|
|
"Horizontal viewport was given unbounded width.\n" +
|
|
"Viewports expand in the scrolling direction to fill their container." +
|
|
"In this case, a horizontal viewport was given an unlimited amount of " +
|
|
"horizontal space in which to expand. This situation typically happens " +
|
|
"when a scrollable widget is nested inside another scrollable widget.\n" +
|
|
"If this widget is always nested in a scrollable widget there " +
|
|
"is no need to use a viewport because there will always be enough " +
|
|
"horizontal space for the children. In this case, consider using a " +
|
|
"Row instead. Otherwise, consider using the \"shrinkWrap\" property " +
|
|
"(or a ShrinkWrappingViewport) to size the width of the viewport " +
|
|
"to the sum of the widths of its children."
|
|
);
|
|
}
|
|
|
|
if (!this.constraints.hasBoundedHeight) {
|
|
throw new UIWidgetsError(
|
|
"Horizontal viewport was given unbounded height.\n" +
|
|
"Viewports expand in the cross axis to fill their container and " +
|
|
"constrain their children to match their extent in the cross axis. " +
|
|
"In this case, a horizontal viewport was given an unlimited amount of " +
|
|
"vertical space in which to expand."
|
|
);
|
|
}
|
|
|
|
break;
|
|
}
|
|
}
|
|
|
|
return true;
|
|
});
|
|
|
|
this.size = this.constraints.biggest;
|
|
|
|
switch (this.axis) {
|
|
case Axis.vertical:
|
|
this.offset.applyViewportDimension(this.size.height);
|
|
break;
|
|
case Axis.horizontal:
|
|
this.offset.applyViewportDimension(this.size.width);
|
|
break;
|
|
}
|
|
}
|
|
|
|
const int _maxLayoutCycles = 10;
|
|
|
|
double _minScrollExtent;
|
|
double _maxScrollExtent;
|
|
bool _hasVisualOverflow = false;
|
|
|
|
protected override void performLayout() {
|
|
if (this.center == null) {
|
|
D.assert(this.firstChild == null);
|
|
this._minScrollExtent = 0.0;
|
|
this._maxScrollExtent = 0.0;
|
|
this._hasVisualOverflow = false;
|
|
this.offset.applyContentDimensions(0.0, 0.0);
|
|
return;
|
|
}
|
|
|
|
double mainAxisExtent = 0.0;
|
|
double crossAxisExtent = 0.0;
|
|
switch (this.axis) {
|
|
case Axis.vertical:
|
|
mainAxisExtent = this.size.height;
|
|
crossAxisExtent = this.size.width;
|
|
break;
|
|
case Axis.horizontal:
|
|
mainAxisExtent = this.size.width;
|
|
crossAxisExtent = this.size.height;
|
|
break;
|
|
}
|
|
|
|
double centerOffsetAdjustment = this.center.centerOffsetAdjustment;
|
|
|
|
int count = 0;
|
|
do {
|
|
var correction = this._attemptLayout(mainAxisExtent, crossAxisExtent,
|
|
this.offset.pixels + centerOffsetAdjustment);
|
|
if (correction != 0.0) {
|
|
this.offset.correctBy(correction);
|
|
}
|
|
else {
|
|
if (this.offset.applyContentDimensions(
|
|
Math.Min(0.0, this._minScrollExtent + mainAxisExtent * this.anchor),
|
|
Math.Max(0.0, this._maxScrollExtent - mainAxisExtent * (1.0 - this.anchor))
|
|
)) {
|
|
break;
|
|
}
|
|
}
|
|
|
|
count += 1;
|
|
} while (count < _maxLayoutCycles);
|
|
|
|
D.assert(() => {
|
|
if (count >= _maxLayoutCycles) {
|
|
D.assert(count != 1);
|
|
throw new UIWidgetsError(
|
|
"A RenderViewport exceeded its maximum number of layout cycles.\n" +
|
|
"RenderViewport render objects, during layout, can retry if either their " +
|
|
"slivers or their ViewportOffset decide that the offset should be corrected " +
|
|
"to take into account information collected during that layout.\n" +
|
|
"In the case of this RenderViewport object, however, this happened $count " +
|
|
"times and still there was no consensus on the scroll offset. This usually " +
|
|
"indicates a bug. Specifically, it means that one of the following three " +
|
|
"problems is being experienced by the RenderViewport object:\n" +
|
|
" * One of the RenderSliver children or the ViewportOffset have a bug such" +
|
|
" that they always think that they need to correct the offset regardless.\n" +
|
|
" * Some combination of the RenderSliver children and the ViewportOffset" +
|
|
" have a bad interaction such that one applies a correction then another" +
|
|
" applies a reverse correction, leading to an infinite loop of corrections.\n" +
|
|
" * There is a pathological case that would eventually resolve, but it is" +
|
|
" so complicated that it cannot be resolved in any reasonable number of" +
|
|
" layout passes."
|
|
);
|
|
}
|
|
|
|
return true;
|
|
});
|
|
}
|
|
|
|
double _attemptLayout(double mainAxisExtent, double crossAxisExtent, double correctedOffset) {
|
|
D.assert(!mainAxisExtent.isNaN());
|
|
D.assert(mainAxisExtent >= 0.0);
|
|
D.assert(crossAxisExtent.isFinite());
|
|
D.assert(crossAxisExtent >= 0.0);
|
|
D.assert(correctedOffset.isFinite());
|
|
|
|
this._minScrollExtent = 0.0;
|
|
this._maxScrollExtent = 0.0;
|
|
this._hasVisualOverflow = false;
|
|
|
|
double centerOffset = mainAxisExtent * this.anchor - correctedOffset;
|
|
double reverseDirectionRemainingPaintExtent = centerOffset.clamp(0.0, mainAxisExtent);
|
|
double forwardDirectionRemainingPaintExtent = (mainAxisExtent - centerOffset).clamp(0.0, mainAxisExtent);
|
|
|
|
double fullCacheExtent = mainAxisExtent + 2 * this.cacheExtent;
|
|
double centerCacheOffset = centerOffset + this.cacheExtent;
|
|
double reverseDirectionRemainingCacheExtent = centerCacheOffset.clamp(0.0, fullCacheExtent);
|
|
double forwardDirectionRemainingCacheExtent =
|
|
(fullCacheExtent - centerCacheOffset).clamp(0.0, fullCacheExtent);
|
|
|
|
RenderSliver leadingNegativeChild = this.childBefore(this.center);
|
|
|
|
if (leadingNegativeChild != null) {
|
|
double result = this.layoutChildSequence(
|
|
child: leadingNegativeChild,
|
|
scrollOffset: Math.Max(mainAxisExtent, centerOffset) - mainAxisExtent,
|
|
overlap: 0.0,
|
|
layoutOffset: forwardDirectionRemainingPaintExtent,
|
|
remainingPaintExtent: reverseDirectionRemainingPaintExtent,
|
|
mainAxisExtent: mainAxisExtent,
|
|
crossAxisExtent: crossAxisExtent,
|
|
growthDirection: GrowthDirection.reverse,
|
|
advance: this.childBefore,
|
|
remainingCacheExtent: reverseDirectionRemainingCacheExtent,
|
|
cacheOrigin: (mainAxisExtent - centerOffset).clamp(-this.cacheExtent, 0.0)
|
|
);
|
|
if (result != 0.0) {
|
|
return -result;
|
|
}
|
|
}
|
|
|
|
return this.layoutChildSequence(
|
|
child: this.center,
|
|
scrollOffset: Math.Max(0.0, -centerOffset),
|
|
overlap: leadingNegativeChild == null ? Math.Min(0.0, -centerOffset) : 0.0,
|
|
layoutOffset: centerOffset >= mainAxisExtent ? centerOffset : reverseDirectionRemainingPaintExtent,
|
|
remainingPaintExtent: forwardDirectionRemainingPaintExtent,
|
|
mainAxisExtent: mainAxisExtent,
|
|
crossAxisExtent: crossAxisExtent,
|
|
growthDirection: GrowthDirection.forward,
|
|
advance: this.childAfter,
|
|
remainingCacheExtent: forwardDirectionRemainingCacheExtent,
|
|
cacheOrigin: centerOffset.clamp(-this.cacheExtent, 0.0)
|
|
);
|
|
}
|
|
|
|
protected override bool hasVisualOverflow {
|
|
get { return this._hasVisualOverflow; }
|
|
}
|
|
|
|
protected override void
|
|
updateOutOfBandData(GrowthDirection growthDirection, SliverGeometry childLayoutGeometry) {
|
|
switch (growthDirection) {
|
|
case GrowthDirection.forward:
|
|
this._maxScrollExtent += childLayoutGeometry.scrollExtent;
|
|
break;
|
|
case GrowthDirection.reverse:
|
|
this._minScrollExtent -= childLayoutGeometry.scrollExtent;
|
|
break;
|
|
}
|
|
|
|
if (childLayoutGeometry.hasVisualOverflow) {
|
|
this._hasVisualOverflow = true;
|
|
}
|
|
}
|
|
|
|
protected override void updateChildLayoutOffset(RenderSliver child, double layoutOffset,
|
|
GrowthDirection growthDirection) {
|
|
var childParentData = (SliverPhysicalParentData) child.parentData;
|
|
childParentData.paintOffset = this.computeAbsolutePaintOffset(child, layoutOffset, growthDirection);
|
|
}
|
|
|
|
protected override Offset paintOffsetOf(RenderSliver child) {
|
|
var childParentData = (SliverPhysicalParentData) child.parentData;
|
|
return childParentData.paintOffset;
|
|
}
|
|
|
|
protected override double scrollOffsetOf(RenderSliver child, double scrollOffsetWithinChild) {
|
|
D.assert(child.parent == this);
|
|
|
|
GrowthDirection growthDirection = child.constraints.growthDirection;
|
|
switch (growthDirection) {
|
|
case GrowthDirection.forward: {
|
|
double scrollOffsetToChild = 0.0;
|
|
RenderSliver current = this.center;
|
|
while (current != child) {
|
|
scrollOffsetToChild += current.geometry.scrollExtent;
|
|
current = this.childAfter(current);
|
|
}
|
|
|
|
return scrollOffsetToChild + scrollOffsetWithinChild;
|
|
}
|
|
case GrowthDirection.reverse: {
|
|
double scrollOffsetToChild = 0.0;
|
|
RenderSliver current = this.childBefore(this.center);
|
|
while (current != child) {
|
|
scrollOffsetToChild -= current.geometry.scrollExtent;
|
|
current = this.childBefore(current);
|
|
}
|
|
|
|
return scrollOffsetToChild - scrollOffsetWithinChild;
|
|
}
|
|
}
|
|
|
|
D.assert(false);
|
|
return 0.0;
|
|
}
|
|
|
|
protected override double maxScrollObstructionExtentBefore(RenderSliver child) {
|
|
D.assert(child.parent == this);
|
|
|
|
GrowthDirection growthDirection = child.constraints.growthDirection;
|
|
switch (growthDirection) {
|
|
case GrowthDirection.forward: {
|
|
double pinnedExtent = 0.0;
|
|
RenderSliver current = this.center;
|
|
while (current != child) {
|
|
pinnedExtent += current.geometry.maxScrollObstructionExtent;
|
|
current = this.childAfter(current);
|
|
}
|
|
|
|
return pinnedExtent;
|
|
}
|
|
case GrowthDirection.reverse: {
|
|
double pinnedExtent = 0.0;
|
|
RenderSliver current = this.childBefore(this.center);
|
|
while (current != child) {
|
|
pinnedExtent += current.geometry.maxScrollObstructionExtent;
|
|
current = this.childBefore(current);
|
|
}
|
|
|
|
return pinnedExtent;
|
|
}
|
|
}
|
|
|
|
D.assert(false);
|
|
return 0.0;
|
|
}
|
|
|
|
public override void applyPaintTransform(RenderObject child, Matrix3 transform) {
|
|
D.assert(child != null);
|
|
|
|
var childParentData = (SliverPhysicalParentData) child.parentData;
|
|
childParentData.applyPaintTransform(transform);
|
|
}
|
|
|
|
protected override double computeChildMainAxisPosition(RenderSliver child, double parentMainAxisPosition) {
|
|
D.assert(child != null);
|
|
D.assert(child.constraints != null);
|
|
SliverPhysicalParentData childParentData = (SliverPhysicalParentData) child.parentData;
|
|
switch (GrowthDirectionUtils.applyGrowthDirectionToAxisDirection(child.constraints.axisDirection,
|
|
child.constraints.growthDirection)) {
|
|
case AxisDirection.down:
|
|
return parentMainAxisPosition - childParentData.paintOffset.dy;
|
|
case AxisDirection.right:
|
|
return parentMainAxisPosition - childParentData.paintOffset.dx;
|
|
case AxisDirection.up:
|
|
return child.geometry.paintExtent - (parentMainAxisPosition - childParentData.paintOffset.dy);
|
|
case AxisDirection.left:
|
|
return child.geometry.paintExtent - (parentMainAxisPosition - childParentData.paintOffset.dx);
|
|
}
|
|
|
|
D.assert(false);
|
|
return 0.0;
|
|
}
|
|
|
|
protected override int indexOfFirstChild {
|
|
get {
|
|
D.assert(this.center != null);
|
|
D.assert(this.center.parent == this);
|
|
D.assert(this.firstChild != null);
|
|
int count = 0;
|
|
RenderSliver child = this.center;
|
|
while (child != this.firstChild) {
|
|
count -= 1;
|
|
child = this.childBefore(child);
|
|
}
|
|
|
|
return count;
|
|
}
|
|
}
|
|
|
|
protected override string labelForChild(int index) {
|
|
if (index == 0) {
|
|
return "center child";
|
|
}
|
|
|
|
return "child " + index;
|
|
}
|
|
|
|
protected override IEnumerable<RenderSliver> childrenInPaintOrder {
|
|
get {
|
|
if (this.firstChild == null) {
|
|
yield break;
|
|
}
|
|
|
|
var child = this.firstChild;
|
|
while (child != this.center) {
|
|
yield return child;
|
|
child = this.childAfter(child);
|
|
}
|
|
|
|
child = this.lastChild;
|
|
while (true) {
|
|
yield return child;
|
|
if (child == this.center) {
|
|
yield break;
|
|
}
|
|
|
|
child = this.childBefore(child);
|
|
}
|
|
}
|
|
}
|
|
|
|
protected override IEnumerable<RenderSliver> childrenInHitTestOrder {
|
|
get {
|
|
if (this.firstChild == null) {
|
|
yield break;
|
|
}
|
|
|
|
RenderSliver child = this.center;
|
|
while (child != null) {
|
|
yield return child;
|
|
child = this.childAfter(child);
|
|
}
|
|
|
|
child = this.childBefore(this.center);
|
|
while (child != null) {
|
|
yield return child;
|
|
child = this.childBefore(child);
|
|
}
|
|
}
|
|
}
|
|
|
|
public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
|
|
base.debugFillProperties(properties);
|
|
properties.add(new DoubleProperty("anchor", this.anchor));
|
|
}
|
|
}
|
|
|
|
public class RenderShrinkWrappingViewport : RenderViewportBase<SliverLogicalContainerParentData> {
|
|
public RenderShrinkWrappingViewport(
|
|
AxisDirection axisDirection = AxisDirection.down,
|
|
AxisDirection crossAxisDirection = AxisDirection.right,
|
|
ViewportOffset offset = null,
|
|
List<RenderSliver> children = null
|
|
) : base(
|
|
axisDirection: axisDirection,
|
|
crossAxisDirection: crossAxisDirection,
|
|
offset: offset) {
|
|
this.addAll(children);
|
|
}
|
|
|
|
public override void setupParentData(RenderObject child) {
|
|
if (!(child.parentData is SliverLogicalContainerParentData)) {
|
|
child.parentData = new SliverLogicalContainerParentData();
|
|
}
|
|
}
|
|
|
|
protected override bool debugThrowIfNotCheckingIntrinsics() {
|
|
D.assert(() => {
|
|
if (!debugCheckingIntrinsics) {
|
|
throw new UIWidgetsError(
|
|
this.GetType() + " does not support returning intrinsic dimensions.\n" +
|
|
"Calculating the intrinsic dimensions would require instantiating every child of " +
|
|
"the viewport, which defeats the point of viewports being lazy.\n" +
|
|
"If you are merely trying to shrink-wrap the viewport in the main axis direction, " +
|
|
"you should be able to achieve that effect by just giving the viewport loose " +
|
|
"constraints, without needing to measure its intrinsic dimensions."
|
|
);
|
|
}
|
|
|
|
return true;
|
|
});
|
|
return true;
|
|
}
|
|
|
|
double _maxScrollExtent = 0.0;
|
|
double _shrinkWrapExtent = 0.0;
|
|
bool _hasVisualOverflow = false;
|
|
|
|
protected override void performLayout() {
|
|
if (this.firstChild == null) {
|
|
switch (this.axis) {
|
|
case Axis.vertical:
|
|
D.assert(this.constraints.hasBoundedWidth);
|
|
this.size = new Size(this.constraints.maxWidth, this.constraints.minHeight);
|
|
break;
|
|
case Axis.horizontal:
|
|
D.assert(this.constraints.hasBoundedHeight);
|
|
this.size = new Size(this.constraints.minWidth, this.constraints.maxHeight);
|
|
break;
|
|
}
|
|
|
|
this.offset.applyViewportDimension(0.0);
|
|
this._maxScrollExtent = 0.0;
|
|
this._shrinkWrapExtent = 0.0;
|
|
this._hasVisualOverflow = false;
|
|
this.offset.applyContentDimensions(0.0, 0.0);
|
|
return;
|
|
}
|
|
|
|
double mainAxisExtent = 0.0;
|
|
double crossAxisExtent = 0.0;
|
|
switch (this.axis) {
|
|
case Axis.vertical:
|
|
D.assert(this.constraints.hasBoundedWidth);
|
|
mainAxisExtent = this.constraints.maxHeight;
|
|
crossAxisExtent = this.constraints.maxWidth;
|
|
break;
|
|
case Axis.horizontal:
|
|
D.assert(this.constraints.hasBoundedHeight);
|
|
mainAxisExtent = this.constraints.maxWidth;
|
|
crossAxisExtent = this.constraints.maxHeight;
|
|
break;
|
|
}
|
|
|
|
double effectiveExtent = 0.0;
|
|
do {
|
|
var correction = this._attemptLayout(mainAxisExtent, crossAxisExtent, this.offset.pixels);
|
|
if (correction != 0.0) {
|
|
this.offset.correctBy(correction);
|
|
}
|
|
else {
|
|
switch (this.axis) {
|
|
case Axis.vertical:
|
|
effectiveExtent = this.constraints.constrainHeight(this._shrinkWrapExtent);
|
|
break;
|
|
case Axis.horizontal:
|
|
effectiveExtent = this.constraints.constrainWidth(this._shrinkWrapExtent);
|
|
break;
|
|
}
|
|
|
|
bool didAcceptViewportDimension = this.offset.applyViewportDimension(effectiveExtent);
|
|
bool didAcceptContentDimension =
|
|
this.offset.applyContentDimensions(0.0, Math.Max(0.0, this._maxScrollExtent - effectiveExtent));
|
|
if (didAcceptViewportDimension && didAcceptContentDimension) {
|
|
break;
|
|
}
|
|
}
|
|
} while (true);
|
|
|
|
switch (this.axis) {
|
|
case Axis.vertical:
|
|
this.size = this.constraints.constrainDimensions(crossAxisExtent, effectiveExtent);
|
|
break;
|
|
case Axis.horizontal:
|
|
this.size = this.constraints.constrainDimensions(effectiveExtent, crossAxisExtent);
|
|
break;
|
|
}
|
|
}
|
|
|
|
double _attemptLayout(double mainAxisExtent, double crossAxisExtent, double correctedOffset) {
|
|
D.assert(!mainAxisExtent.isNaN());
|
|
D.assert(mainAxisExtent >= 0.0);
|
|
D.assert(crossAxisExtent.isFinite());
|
|
D.assert(crossAxisExtent >= 0.0);
|
|
D.assert(correctedOffset.isFinite());
|
|
|
|
this._maxScrollExtent = 0.0;
|
|
this._shrinkWrapExtent = 0.0;
|
|
this._hasVisualOverflow = false;
|
|
|
|
return this.layoutChildSequence(
|
|
child: this.firstChild,
|
|
scrollOffset: Math.Max(0.0, correctedOffset),
|
|
overlap: Math.Min(0.0, correctedOffset),
|
|
layoutOffset: 0.0,
|
|
remainingPaintExtent: mainAxisExtent,
|
|
mainAxisExtent: mainAxisExtent,
|
|
crossAxisExtent: crossAxisExtent,
|
|
growthDirection: GrowthDirection.forward,
|
|
advance: this.childAfter,
|
|
remainingCacheExtent: mainAxisExtent + 2 * this.cacheExtent,
|
|
cacheOrigin: -this.cacheExtent
|
|
);
|
|
}
|
|
|
|
protected override bool hasVisualOverflow {
|
|
get { return this._hasVisualOverflow; }
|
|
}
|
|
|
|
protected override void
|
|
updateOutOfBandData(GrowthDirection growthDirection, SliverGeometry childLayoutGeometry) {
|
|
D.assert(growthDirection == GrowthDirection.forward);
|
|
|
|
this._maxScrollExtent += childLayoutGeometry.scrollExtent;
|
|
if (childLayoutGeometry.hasVisualOverflow) {
|
|
this._hasVisualOverflow = true;
|
|
}
|
|
|
|
this._shrinkWrapExtent += childLayoutGeometry.maxPaintExtent;
|
|
}
|
|
|
|
protected override void updateChildLayoutOffset(RenderSliver child, double layoutOffset,
|
|
GrowthDirection growthDirection) {
|
|
D.assert(growthDirection == GrowthDirection.forward);
|
|
|
|
var childParentData = (SliverLogicalParentData) child.parentData;
|
|
childParentData.layoutOffset = layoutOffset;
|
|
}
|
|
|
|
protected override Offset paintOffsetOf(RenderSliver child) {
|
|
var childParentData = (SliverLogicalParentData) child.parentData;
|
|
return this.computeAbsolutePaintOffset(child, childParentData.layoutOffset, GrowthDirection.forward);
|
|
}
|
|
|
|
protected override double scrollOffsetOf(RenderSliver child, double scrollOffsetWithinChild) {
|
|
D.assert(child.parent == this);
|
|
D.assert(child.constraints.growthDirection == GrowthDirection.forward);
|
|
|
|
double scrollOffsetToChild = 0.0;
|
|
RenderSliver current = this.firstChild;
|
|
while (current != child) {
|
|
scrollOffsetToChild += current.geometry.scrollExtent;
|
|
current = this.childAfter(current);
|
|
}
|
|
|
|
return scrollOffsetToChild + scrollOffsetWithinChild;
|
|
}
|
|
|
|
protected override double maxScrollObstructionExtentBefore(RenderSliver child) {
|
|
D.assert(child.parent == this);
|
|
D.assert(child.constraints.growthDirection == GrowthDirection.forward);
|
|
|
|
double pinnedExtent = 0.0;
|
|
RenderSliver current = this.firstChild;
|
|
while (current != child) {
|
|
pinnedExtent += current.geometry.maxScrollObstructionExtent;
|
|
current = this.childAfter(current);
|
|
}
|
|
|
|
return pinnedExtent;
|
|
}
|
|
|
|
public override void applyPaintTransform(RenderObject child, Matrix3 transform) {
|
|
D.assert(child != null);
|
|
|
|
Offset offset = this.paintOffsetOf((RenderSliver) child);
|
|
transform.preTranslate((float) offset.dx, (float) offset.dy);
|
|
}
|
|
|
|
protected override double computeChildMainAxisPosition(RenderSliver child, double parentMainAxisPosition) {
|
|
D.assert(child != null);
|
|
D.assert(child.constraints != null);
|
|
D.assert(this.hasSize);
|
|
SliverLogicalParentData childParentData = (SliverLogicalParentData) child.parentData;
|
|
switch (GrowthDirectionUtils.applyGrowthDirectionToAxisDirection(
|
|
child.constraints.axisDirection, child.constraints.growthDirection)) {
|
|
case AxisDirection.down:
|
|
case AxisDirection.right:
|
|
return parentMainAxisPosition - childParentData.layoutOffset;
|
|
case AxisDirection.up:
|
|
return (this.size.height - parentMainAxisPosition) - childParentData.layoutOffset;
|
|
case AxisDirection.left:
|
|
return (this.size.width - parentMainAxisPosition) - childParentData.layoutOffset;
|
|
}
|
|
|
|
D.assert(false);
|
|
return 0.0;
|
|
}
|
|
|
|
protected override int indexOfFirstChild {
|
|
get { return 0; }
|
|
}
|
|
|
|
protected override string labelForChild(int index) {
|
|
return "child " + index;
|
|
}
|
|
|
|
|
|
protected override IEnumerable<RenderSliver> childrenInPaintOrder {
|
|
get {
|
|
RenderSliver child = this.firstChild;
|
|
while (child != null) {
|
|
yield return child;
|
|
child = this.childAfter(child);
|
|
}
|
|
}
|
|
}
|
|
|
|
protected override IEnumerable<RenderSliver> childrenInHitTestOrder {
|
|
get {
|
|
RenderSliver child = this.lastChild;
|
|
while (child != null) {
|
|
yield return child;
|
|
child = this.childBefore(child);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|