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ab01c7bf73
Use the same technique for updating compositing bits as layout and painting. This avoids walking the entire rendering tree when all you need to update is a small subtree.
1464 lines
54 KiB
Dart
1464 lines
54 KiB
Dart
// Copyright 2015 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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import 'dart:developer';
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import 'dart:math' as math;
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import 'dart:ui' as ui;
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import 'package:flutter/gestures.dart';
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import 'package:flutter/scheduler.dart';
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import 'package:vector_math/vector_math_64.dart';
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import 'debug.dart';
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import 'layer.dart';
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import 'node.dart';
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export 'layer.dart';
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export 'package:flutter/gestures.dart' show HitTestEntry, HitTestResult;
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typedef ui.Shader ShaderCallback(Rect bounds);
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/// Base class for data associated with a [RenderObject] by its parent.
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///
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/// Some render objects wish to store data on their children, such as their
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/// input parameters to the parent's layout algorithm or their position relative
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/// to other children.
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class ParentData {
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/// Called when the RenderObject is removed from the tree.
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void detach() { }
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/// Override this function in subclasses to merge in data from other instance
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/// into this instance.
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void merge(ParentData other) {
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assert(other.runtimeType == this.runtimeType);
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}
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String toString() => '<none>';
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}
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typedef void PaintingContextCallback(PaintingContext context, Offset offset);
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/// A place to paint.
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///
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/// Rather than holding a canvas directly, render objects paint using a painting
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/// context. The painting context has a canvas, which receives the
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/// individual draw operations, and also has functions for painting child
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/// render objects.
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///
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/// When painting a child render object, the canvas held by the painting context
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/// can change because the draw operations issued before and after painting the
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/// child might be recorded in separate compositing layers. For this reason, do
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/// not hold a reference to the canvas across operations that might paint
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/// child render objects.
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class PaintingContext {
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PaintingContext._(this._containerLayer, this._paintBounds) {
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assert(_containerLayer != null);
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assert(_paintBounds != null);
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}
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final ContainerLayer _containerLayer;
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final Rect _paintBounds;
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/// Repaint the given render object.
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///
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/// The render object must have a composited layer and must be in need of
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/// painting. The render object's layer is re-used, along with any layers in
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/// the subtree that don't need to be repainted.
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static void repaintCompositedChild(RenderObject child) {
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assert(child.hasLayer);
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assert(child.needsPaint);
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child._layer ??= new ContainerLayer();
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child._layer.removeAllChildren();
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assert(() {
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child._layer.debugOwner = child.debugOwner ?? child.runtimeType;
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return true;
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});
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PaintingContext childContext = new PaintingContext._(child._layer, child.paintBounds);
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child._paintWithContext(childContext, Offset.zero);
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childContext._stopRecordingIfNeeded();
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}
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/// Paint a child render object.
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///
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/// If the child has its own composited layer, the child will be composited
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/// into the layer subtree associated with this painting context. Otherwise,
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/// the child will be painted into the current PictureLayer for this context.
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void paintChild(RenderObject child, Offset offset) {
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if (child.hasLayer) {
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_stopRecordingIfNeeded();
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_compositeChild(child, offset);
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} else {
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child._paintWithContext(this, offset);
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}
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}
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void _compositeChild(RenderObject child, Offset offset) {
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assert(!_isRecording);
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assert(child.hasLayer);
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assert(_canvas == null || _canvas.getSaveCount() == 1);
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// Create a layer for our child, and paint the child into it.
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if (child.needsPaint) {
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repaintCompositedChild(child);
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} else {
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assert(child._layer != null);
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child._layer.detach();
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assert(() {
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child._layer.debugOwner = child.debugOwner ?? child.runtimeType;
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return true;
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});
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}
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_appendLayer(child._layer, offset);
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}
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void _appendLayer(Layer layer, Offset offset) {
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assert(!_isRecording);
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layer.offset = offset;
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_containerLayer.append(layer);
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}
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bool get _isRecording {
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final bool hasCanvas = (_canvas != null);
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assert(() {
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if (hasCanvas) {
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assert(_currentLayer != null);
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assert(_recorder != null);
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assert(_canvas != null);
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} else {
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assert(_currentLayer == null);
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assert(_recorder == null);
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assert(_canvas == null);
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}
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return true;
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});
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return hasCanvas;
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}
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// Recording state
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PictureLayer _currentLayer;
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ui.PictureRecorder _recorder;
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Canvas _canvas;
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/// The canvas on which to paint.
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///
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/// The current canvas can change whenever you paint a child using this
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/// context, which means it's fragile to hold a reference to the canvas
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/// returned by this getter.
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Canvas get canvas {
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if (_canvas == null)
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_startRecording();
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return _canvas;
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}
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void _startRecording() {
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assert(!_isRecording);
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_currentLayer = new PictureLayer(paintBounds: _paintBounds);
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_recorder = new ui.PictureRecorder();
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_canvas = new Canvas(_recorder, _paintBounds);
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_containerLayer.append(_currentLayer);
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}
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void _stopRecordingIfNeeded() {
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if (!_isRecording)
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return;
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assert(() {
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if (debugEnableRepaintRainbox)
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canvas.drawRect(_paintBounds, new Paint()..color = debugCurrentRepaintColor.toColor());
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if (debugPaintLayerBordersEnabled) {
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Paint paint = new Paint()
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..style = ui.PaintingStyle.stroke
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..strokeWidth = 1.0
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..color = debugPaintLayerBordersColor;
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canvas.drawRect(_paintBounds, paint);
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}
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return true;
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});
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_currentLayer.picture = _recorder.endRecording();
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_currentLayer = null;
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_recorder = null;
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_canvas = null;
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}
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static final Paint _disableAntialias = new Paint()..isAntiAlias = false;
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/// Push a statistics overlay.
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///
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/// Statistics overlays are always composited because they're drawn by the
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/// compositor.
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void pushStatistics(Offset offset, int optionsMask, int rasterizerThreshold, Size size) {
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_stopRecordingIfNeeded();
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StatisticsLayer statisticsLayer = new StatisticsLayer(
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paintBounds: new Rect.fromLTWH(0.0, 0.0, size.width, size.height),
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optionsMask: optionsMask,
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rasterizerThreshold: rasterizerThreshold
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);
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_appendLayer(statisticsLayer, offset);
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}
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/// Push a rectangular clip rect.
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///
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/// This function will call painter synchronously with a painting context that
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/// is clipped by the given clip. The given clip should not incorporate the
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/// painting offset.
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void pushClipRect(bool needsCompositing, Offset offset, Rect clipRect, PaintingContextCallback painter) {
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if (needsCompositing) {
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_stopRecordingIfNeeded();
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ClipRectLayer clipLayer = new ClipRectLayer(clipRect: clipRect);
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_appendLayer(clipLayer, offset);
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PaintingContext childContext = new PaintingContext._(clipLayer, clipRect);
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painter(childContext, Offset.zero);
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childContext._stopRecordingIfNeeded();
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} else {
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canvas.save();
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canvas.clipRect(clipRect.shift(offset));
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painter(this, offset);
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canvas.restore();
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}
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}
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/// Push a rounded-rect clip rect.
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///
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/// This function will call painter synchronously with a painting context that
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/// is clipped by the given clip. The given clip should not incorporate the
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/// painting offset.
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void pushClipRRect(bool needsCompositing, Offset offset, Rect bounds, ui.RRect clipRRect, PaintingContextCallback painter) {
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if (needsCompositing) {
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_stopRecordingIfNeeded();
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ClipRRectLayer clipLayer = new ClipRRectLayer(bounds: bounds, clipRRect: clipRRect);
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_appendLayer(clipLayer, offset);
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PaintingContext childContext = new PaintingContext._(clipLayer, bounds);
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painter(childContext, Offset.zero);
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childContext._stopRecordingIfNeeded();
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} else {
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canvas.saveLayer(bounds.shift(offset), _disableAntialias);
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// TODO(abarth): Remove this translation once RRect.shift works again.
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canvas.translate(offset.dx, offset.dy);
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canvas.clipRRect(clipRRect);
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painter(this, Offset.zero);
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canvas.restore();
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}
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}
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/// Push a path clip.
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///
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/// This function will call painter synchronously with a painting context that
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/// is clipped by the given clip. The given clip should not incorporate the
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/// painting offset.
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void pushClipPath(bool needsCompositing, Offset offset, Rect bounds, Path clipPath, PaintingContextCallback painter) {
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if (needsCompositing) {
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_stopRecordingIfNeeded();
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ClipPathLayer clipLayer = new ClipPathLayer(bounds: bounds, clipPath: clipPath);
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_appendLayer(clipLayer, offset);
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PaintingContext childContext = new PaintingContext._(clipLayer, bounds);
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painter(childContext, Offset.zero);
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childContext._stopRecordingIfNeeded();
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} else {
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canvas.saveLayer(bounds.shift(offset), _disableAntialias);
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canvas.clipPath(clipPath.shift(offset));
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painter(this, offset);
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canvas.restore();
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}
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}
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/// Push a transform.
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///
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/// This function will call painter synchronously with a painting context that
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/// is transformed by the given transform. The given transform should not
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/// incorporate the painting offset.
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void pushTransform(bool needsCompositing, Offset offset, Matrix4 transform, PaintingContextCallback painter) {
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if (needsCompositing) {
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_stopRecordingIfNeeded();
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TransformLayer transformLayer = new TransformLayer(transform: transform);
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_appendLayer(transformLayer, offset);
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PaintingContext childContext = new PaintingContext._(transformLayer, _paintBounds);
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painter(childContext, Offset.zero);
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childContext._stopRecordingIfNeeded();
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} else {
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Matrix4 offsetMatrix = new Matrix4.translationValues(offset.dx, offset.dy, 0.0);
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Matrix4 transformWithOffset = offsetMatrix * transform;
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canvas.save();
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canvas.concat(transformWithOffset.storage);
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painter(this, Offset.zero);
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canvas.restore();
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}
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}
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static Paint _getPaintForAlpha(int alpha) {
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return new Paint()
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..color = new Color.fromARGB(alpha, 0, 0, 0)
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..transferMode = TransferMode.srcOver
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..isAntiAlias = false;
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}
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/// Push an opacity layer.
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///
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/// This function will call painter synchronously with a painting context that
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/// will be blended with the given alpha value.
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void pushOpacity(bool needsCompositing, Offset offset, Rect bounds, int alpha, PaintingContextCallback painter) {
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if (needsCompositing) {
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_stopRecordingIfNeeded();
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OpacityLayer opacityLayer = new OpacityLayer(bounds: bounds, alpha: alpha);
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_appendLayer(opacityLayer, offset);
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PaintingContext childContext = new PaintingContext._(opacityLayer, _paintBounds);
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painter(childContext, Offset.zero);
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childContext._stopRecordingIfNeeded();
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} else {
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// TODO(abarth): pushOpacity should require bounds.
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canvas.saveLayer(bounds?.shift(offset), _getPaintForAlpha(alpha));
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painter(this, offset);
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canvas.restore();
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}
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}
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static Paint _getPaintForShaderMask(Rect bounds,
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ShaderCallback shaderCallback,
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TransferMode transferMode) {
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return new Paint()
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..transferMode = transferMode
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..shader = shaderCallback(bounds);
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}
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/// Push a shader mask.
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///
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/// This function will call painter synchronously with a painting context that
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/// will be masked with the given shader.
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///
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/// WARNING: This function does not yet support compositing.
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void pushShaderMask(bool needsCompositing, Offset offset, Rect bounds, ShaderCallback shaderCallback, TransferMode transferMode, PaintingContextCallback painter) {
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assert(!needsCompositing); // TODO(abarth): Implement compositing for shader masks.
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canvas.saveLayer(bounds.shift(offset), _disableAntialias);
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painter(this, offset);
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Paint shaderPaint = _getPaintForShaderMask(bounds, shaderCallback, transferMode);
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canvas.drawRect(bounds, shaderPaint);
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canvas.restore();
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}
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}
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/// An encapsulation of a renderer and a paint() method.
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///
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/// A renderer may allow its paint() method to be augmented or redefined by
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/// providing a Painter. See for example overlayPainter in BlockViewport.
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abstract class Painter {
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RenderObject get renderObject => _renderObject;
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RenderObject _renderObject;
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void attach(RenderObject renderObject) {
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assert(_renderObject == null);
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_renderObject = renderObject;
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}
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void detach() {
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assert(_renderObject != null);
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_renderObject = null;
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}
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void paint(PaintingContext context, Offset offset);
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}
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/// An abstract set of layout constraints.
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///
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/// Concrete layout models (such as box) will create concrete subclasses to
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/// communicate layout constraints between parents and children.
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abstract class Constraints {
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const Constraints();
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/// Whether there is exactly one size possible given these constraints
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bool get isTight;
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/// Whether the constraint is expressed in a consistent manner.
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bool get isNormalized;
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}
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typedef void RenderObjectVisitor(RenderObject child);
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typedef void LayoutCallback(Constraints constraints);
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typedef double ExtentCallback(Constraints constraints);
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typedef void RenderingExceptionHandler(RenderObject source, String method, dynamic exception, StackTrace stack);
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/// This callback is invoked whenever an exception is caught by the rendering
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/// system. The 'source' argument is the [RenderObject] object that caught the
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/// exception. The 'method' argument is the method in which the exception
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/// occurred; it will be one of 'performResize', 'performLayout, or 'paint'. The
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/// 'exception' argument contains the object that was thrown, and the 'stack'
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/// argument contains the stack trace. The callback is invoked after the
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/// information is printed to the console, and could be used to print additional
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/// information, such as from [debugDumpRenderTree()].
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RenderingExceptionHandler debugRenderingExceptionHandler;
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/// An object in the render tree.
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///
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/// Render objects have a reference to their parent but do not commit to a model
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/// for their children.
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abstract class RenderObject extends AbstractNode implements HitTestTarget {
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RenderObject() {
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_needsCompositing = hasLayer;
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}
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// LAYOUT
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/// Data for use by the parent render object.
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///
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/// The parent data is used by the render object that lays out this object
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/// (typically this object's parent in the render tree) to store information
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/// relevant to itself and to any other nodes who happen to know exactly what
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/// the data means. The parent data is opaque to the child.
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///
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/// - The parent data field must not be directly set, except by calling
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/// [setupParentData] on the parent node.
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/// - The parent data can be set before the child is added to the parent, by
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/// calling [setupParentData] on the future parent node.
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/// - The conventions for using the parent data depend on the layout protocol
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/// used between the parent and child. For example, in box layout, the
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/// parent data is completely opaque but in sector layout the child is
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/// permitted to read some fields of the parent data.
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ParentData parentData;
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/// Override to setup parent data correctly for your children.
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///
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/// You can call this function to set up the parent data for child before the
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/// child is added to the parent's child list.
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void setupParentData(RenderObject child) {
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assert(debugCanPerformMutations);
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if (child.parentData is! ParentData)
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child.parentData = new ParentData();
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}
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/// Called by subclasses when they decide a render object is a child.
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///
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/// Only for use by subclasses when changing their child lists. Calling this
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/// in other cases will lead to an inconsistent tree and probably cause crashes.
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void adoptChild(RenderObject child) {
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assert(debugCanPerformMutations);
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assert(child != null);
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setupParentData(child);
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super.adoptChild(child);
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markNeedsLayout();
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_markNeedsCompositingBitsUpdate();
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}
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/// Called by subclasses when they decide a render object is no longer a child.
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///
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/// Only for use by subclasses when changing their child lists. Calling this
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/// in other cases will lead to an inconsistent tree and probably cause crashes.
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void dropChild(RenderObject child) {
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assert(debugCanPerformMutations);
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assert(child != null);
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assert(child.parentData != null);
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child._cleanRelayoutSubtreeRoot();
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child.parentData.detach();
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child.parentData = null;
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super.dropChild(child);
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markNeedsLayout();
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_markNeedsCompositingBitsUpdate();
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}
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/// Calls visitor for each immediate child of this render object.
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///
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/// Override in subclasses with children and call the visitor for each child
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void visitChildren(RenderObjectVisitor visitor) { }
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dynamic debugOwner;
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void _debugReportException(String method, dynamic exception, StackTrace stack) {
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debugPrint('-- EXCEPTION --');
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debugPrint('The following exception was raised during $method():');
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debugPrint('$exception');
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debugPrint('Stack trace:');
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debugPrint('$stack');
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debugPrint('The following RenderObject was being processed when the exception was fired:\n${this}');
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if (debugOwner != null)
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debugPrint('That RenderObject had the following owner:\n$debugOwner');
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if (debugRenderingExceptionHandler != null)
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debugRenderingExceptionHandler(this, method, exception, stack);
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}
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static bool _debugDoingLayout = false;
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static bool get debugDoingLayout => _debugDoingLayout;
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bool _debugDoingThisResize = false;
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bool get debugDoingThisResize => _debugDoingThisResize;
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bool _debugDoingThisLayout = false;
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bool get debugDoingThisLayout => _debugDoingThisLayout;
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static RenderObject _debugActiveLayout = null;
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static RenderObject get debugActiveLayout => _debugActiveLayout;
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bool _debugMutationsLocked = false;
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bool _debugCanParentUseSize;
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bool get debugCanParentUseSize => _debugCanParentUseSize;
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bool get debugCanPerformMutations {
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RenderObject node = this;
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while (true) {
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if (node._doingThisLayoutWithCallback)
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return true;
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if (node._debugMutationsLocked)
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return false;
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if (node.parent is! RenderObject)
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return true;
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node = node.parent;
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}
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}
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static List<RenderObject> _nodesNeedingLayout = <RenderObject>[];
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bool _needsLayout = true;
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/// Whether this render object's layout information is dirty.
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bool get needsLayout => _needsLayout;
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RenderObject _relayoutSubtreeRoot;
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bool _doingThisLayoutWithCallback = false;
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Constraints _constraints;
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/// The layout constraints most recently supplied by the parent.
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Constraints get constraints => _constraints;
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/// Override this function in a subclass to verify that your state matches the constraints object.
|
|
bool debugDoesMeetConstraints();
|
|
bool debugAncestorsAlreadyMarkedNeedsLayout() {
|
|
if (_relayoutSubtreeRoot == null)
|
|
return true; // we haven't yet done layout even once, so there's nothing for us to do
|
|
RenderObject node = this;
|
|
while (node != _relayoutSubtreeRoot) {
|
|
assert(node._relayoutSubtreeRoot == _relayoutSubtreeRoot);
|
|
assert(node.parent != null);
|
|
node = node.parent;
|
|
if ((!node._needsLayout) && (!node._debugDoingThisLayout))
|
|
return false;
|
|
}
|
|
assert(node._relayoutSubtreeRoot == node);
|
|
return true;
|
|
}
|
|
|
|
/// Mark this render object's layout information as dirty.
|
|
///
|
|
/// Rather than eagerly updating layout information in response to writes into
|
|
/// this render object, we instead mark the layout information as dirty, which
|
|
/// schedules a visual update. As part of the visual update, the rendering
|
|
/// pipeline will update this render object's layout information.
|
|
///
|
|
/// This mechanism batches the layout work so that multiple sequential writes
|
|
/// are coalesced, removing redundant computation.
|
|
///
|
|
/// Causes [needsLayout] to return true for this render object. If the parent
|
|
/// render object indicated that it uses the size of this render object in
|
|
/// computing its layout information, this function will also mark the parent
|
|
/// as needing layout.
|
|
void markNeedsLayout() {
|
|
assert(debugCanPerformMutations);
|
|
if (_needsLayout) {
|
|
assert(debugAncestorsAlreadyMarkedNeedsLayout());
|
|
return;
|
|
}
|
|
_needsLayout = true;
|
|
assert(_relayoutSubtreeRoot != null);
|
|
if (_relayoutSubtreeRoot != this) {
|
|
final RenderObject parent = this.parent;
|
|
if (!_doingThisLayoutWithCallback) {
|
|
parent.markNeedsLayout();
|
|
} else {
|
|
assert(parent._debugDoingThisLayout);
|
|
}
|
|
assert(parent == this.parent);
|
|
} else {
|
|
_nodesNeedingLayout.add(this);
|
|
Scheduler.instance.ensureVisualUpdate();
|
|
}
|
|
}
|
|
|
|
void _cleanRelayoutSubtreeRoot() {
|
|
if (_relayoutSubtreeRoot != this) {
|
|
_relayoutSubtreeRoot = null;
|
|
_needsLayout = true;
|
|
visitChildren((RenderObject child) {
|
|
child._cleanRelayoutSubtreeRoot();
|
|
});
|
|
}
|
|
}
|
|
|
|
/// Bootstrap the rendering pipeline by scheduling the very first layout.
|
|
///
|
|
/// Requires this render object to be attached and that this render object
|
|
/// is the root of the render tree.
|
|
///
|
|
/// See [RenderView] for an example of how this function is used.
|
|
void scheduleInitialLayout() {
|
|
assert(attached);
|
|
assert(parent is! RenderObject);
|
|
assert(!_debugDoingLayout);
|
|
assert(_relayoutSubtreeRoot == null);
|
|
_relayoutSubtreeRoot = this;
|
|
assert(() {
|
|
_debugCanParentUseSize = false;
|
|
return true;
|
|
});
|
|
_nodesNeedingLayout.add(this);
|
|
}
|
|
|
|
/// Update the layout information for all dirty render objects.
|
|
///
|
|
/// This function is one of the core stages of the rendering pipeline. Layout
|
|
/// information is cleaned prior to painting so that render objects will
|
|
/// appear on screen in their up-to-date locations.
|
|
///
|
|
/// See [FlutterBinding] for an example of how this function is used.
|
|
static void flushLayout() {
|
|
Timeline.startSync('Layout');
|
|
_debugDoingLayout = true;
|
|
try {
|
|
// TODO(ianh): assert that we're not allowing previously dirty nodes to redirty themeselves
|
|
while (_nodesNeedingLayout.isNotEmpty) {
|
|
List<RenderObject> dirtyNodes = _nodesNeedingLayout;
|
|
_nodesNeedingLayout = <RenderObject>[];
|
|
for (RenderObject node in dirtyNodes..sort((RenderObject a, RenderObject b) => a.depth - b.depth)) {
|
|
if (node._needsLayout && node.attached)
|
|
node._layoutWithoutResize();
|
|
}
|
|
}
|
|
} finally {
|
|
_debugDoingLayout = false;
|
|
Timeline.finishSync();
|
|
}
|
|
}
|
|
void _layoutWithoutResize() {
|
|
assert(_relayoutSubtreeRoot == this);
|
|
RenderObject debugPreviousActiveLayout;
|
|
assert(!_debugMutationsLocked);
|
|
assert(!_doingThisLayoutWithCallback);
|
|
assert(_debugCanParentUseSize != null);
|
|
assert(() {
|
|
_debugMutationsLocked = true;
|
|
_debugDoingThisLayout = true;
|
|
debugPreviousActiveLayout = _debugActiveLayout;
|
|
_debugActiveLayout = this;
|
|
return true;
|
|
});
|
|
try {
|
|
performLayout();
|
|
} catch (e, stack) {
|
|
_debugReportException('performLayout', e, stack);
|
|
}
|
|
assert(() {
|
|
_debugActiveLayout = debugPreviousActiveLayout;
|
|
_debugDoingThisLayout = false;
|
|
_debugMutationsLocked = false;
|
|
return true;
|
|
});
|
|
_needsLayout = false;
|
|
markNeedsPaint();
|
|
}
|
|
|
|
/// Compute the layout for this render object.
|
|
///
|
|
/// This function is the main entry point for parents to ask their children to
|
|
/// update their layout information. The parent passes a constraints object,
|
|
/// which informs the child as which layouts are permissible. The child is
|
|
/// required to obey the given constraints.
|
|
///
|
|
/// If the parent reads information computed during the child's layout, the
|
|
/// parent must pass true for parentUsesSize. In that case, the parent will be
|
|
/// marked as needing layout whenever the child is marked as needing layout
|
|
/// because the parent's layout information depends on the child's layout
|
|
/// information. If the parent uses the default value (false) for
|
|
/// parentUsesSize, the child can change its layout information (subject to
|
|
/// the given constraints) without informing the parent.
|
|
///
|
|
/// Subclasses should not override layout directly. Instead, they should
|
|
/// override performResize and/or performLayout.
|
|
///
|
|
/// The parent's performLayout method should call the layout of all its
|
|
/// children unconditionally. It is the layout functions's responsibility (as
|
|
/// implemented here) to return early if the child does not need to do any
|
|
/// work to update its layout information.
|
|
void layout(Constraints constraints, { bool parentUsesSize: false }) {
|
|
assert(constraints.isNormalized);
|
|
assert(!_debugDoingThisResize);
|
|
assert(!_debugDoingThisLayout);
|
|
final RenderObject parent = this.parent;
|
|
RenderObject relayoutSubtreeRoot;
|
|
if (!parentUsesSize || sizedByParent || constraints.isTight || parent is! RenderObject)
|
|
relayoutSubtreeRoot = this;
|
|
else
|
|
relayoutSubtreeRoot = parent._relayoutSubtreeRoot;
|
|
assert(parent == this.parent);
|
|
assert(() {
|
|
_debugCanParentUseSize = parentUsesSize;
|
|
return true;
|
|
});
|
|
if (!needsLayout && constraints == _constraints && relayoutSubtreeRoot == _relayoutSubtreeRoot) {
|
|
assert(() {
|
|
// in case parentUsesSize changed since the last invocation, set size
|
|
// to itself, so it has the right internal debug values.
|
|
_debugDoingThisResize = sizedByParent;
|
|
_debugDoingThisLayout = !sizedByParent;
|
|
RenderObject debugPreviousActiveLayout = _debugActiveLayout;
|
|
_debugActiveLayout = this;
|
|
debugResetSize();
|
|
_debugActiveLayout = debugPreviousActiveLayout;
|
|
_debugDoingThisLayout = false;
|
|
_debugDoingThisResize = false;
|
|
return true;
|
|
});
|
|
return;
|
|
}
|
|
_constraints = constraints;
|
|
_relayoutSubtreeRoot = relayoutSubtreeRoot;
|
|
assert(!_debugMutationsLocked);
|
|
assert(!_doingThisLayoutWithCallback);
|
|
assert(() {
|
|
_debugMutationsLocked = true;
|
|
return true;
|
|
});
|
|
if (sizedByParent) {
|
|
assert(() { _debugDoingThisResize = true; return true; });
|
|
try {
|
|
performResize();
|
|
assert(debugDoesMeetConstraints());
|
|
} catch (e, stack) {
|
|
_debugReportException('performResize', e, stack);
|
|
}
|
|
assert(() { _debugDoingThisResize = false; return true; });
|
|
}
|
|
RenderObject debugPreviousActiveLayout;
|
|
assert(() {
|
|
_debugDoingThisLayout = true;
|
|
debugPreviousActiveLayout = _debugActiveLayout;
|
|
_debugActiveLayout = this;
|
|
return true;
|
|
});
|
|
try {
|
|
performLayout();
|
|
assert(debugDoesMeetConstraints());
|
|
} catch (e, stack) {
|
|
_debugReportException('performLayout', e, stack);
|
|
}
|
|
assert(() {
|
|
_debugActiveLayout = debugPreviousActiveLayout;
|
|
_debugDoingThisLayout = false;
|
|
_debugMutationsLocked = false;
|
|
return true;
|
|
});
|
|
_needsLayout = false;
|
|
markNeedsPaint();
|
|
assert(parent == this.parent);
|
|
}
|
|
|
|
/// If a subclass has a "size" (the state controlled by "parentUsesSize",
|
|
/// whatever it is in the subclass, e.g. the actual "size" property of
|
|
/// RenderBox), and the subclass verifies that in checked mode this "size"
|
|
/// property isn't used when debugCanParentUseSize isn't set, then that
|
|
/// subclass should override debugResetSize() to reapply the current values of
|
|
/// debugCanParentUseSize to that state.
|
|
void debugResetSize() { }
|
|
|
|
/// Whether the constraints are the only input to the sizing algorithm (in
|
|
/// particular, child nodes have no impact).
|
|
///
|
|
/// Returning false is always correct, but returning true can be more
|
|
/// efficient when computing the size of this render object because we don't
|
|
/// need to recompute the size if the constraints don't change.
|
|
bool get sizedByParent => false;
|
|
|
|
/// Updates the render objects size using only the constraints.
|
|
///
|
|
/// Do not call this function directly: call [layout] instead. This function
|
|
/// is called by [layout] when there is actually work to be done by this
|
|
/// render object during layout. The layout constraints provided by your
|
|
/// parent are available via the [constraints] getter.
|
|
///
|
|
/// Subclasses that set [sizedByParent] to true should override this function
|
|
/// to compute their size.
|
|
///
|
|
/// Note: This function is called only if [sizedByParent] is true.
|
|
void performResize();
|
|
|
|
/// Do the work of computing the layout for this render object.
|
|
///
|
|
/// Do not call this function directly: call [layout] instead. This function
|
|
/// is called by [layout] when there is actually work to be done by this
|
|
/// render object during layout. The layout constraints provided by your
|
|
/// parent are available via the [constraints] getter.
|
|
///
|
|
/// If [sizedByParent] is true, then this function should not actually change
|
|
/// the dimensions of this render object. Instead, that work should be done by
|
|
/// [performResize]. If [sizedByParent] is false, then this function should
|
|
/// both change the dimensions of this render object and instruct its children
|
|
/// to layout.
|
|
///
|
|
/// In implementing this function, you must call [layout] on each of your
|
|
/// children, passing true for parentUsesSize if your layout information is
|
|
/// dependent on your child's layout information. Passing true for
|
|
/// parentUsesSize ensures that this render object will undergo layout if the
|
|
/// child undergoes layout. Otherwise, the child can changes its layout
|
|
/// information without informing this render object.
|
|
void performLayout();
|
|
|
|
/// Allows this render object to mutation its child list during layout and
|
|
/// invokes callback.
|
|
void invokeLayoutCallback(LayoutCallback callback) {
|
|
assert(_debugMutationsLocked);
|
|
assert(_debugDoingThisLayout);
|
|
assert(!_doingThisLayoutWithCallback);
|
|
_doingThisLayoutWithCallback = true;
|
|
try {
|
|
callback(constraints);
|
|
} finally {
|
|
_doingThisLayoutWithCallback = false;
|
|
}
|
|
}
|
|
|
|
/// Rotate this render object (not yet implemented).
|
|
void rotate({
|
|
int oldAngle, // 0..3
|
|
int newAngle, // 0..3
|
|
Duration time
|
|
}) { }
|
|
|
|
// when the parent has rotated (e.g. when the screen has been turned
|
|
// 90 degrees), immediately prior to layout() being called for the
|
|
// new dimensions, rotate() is called with the old and new angles.
|
|
// The next time paint() is called, the coordinate space will have
|
|
// been rotated N quarter-turns clockwise, where:
|
|
// N = newAngle-oldAngle
|
|
// ...but the rendering is expected to remain the same, pixel for
|
|
// pixel, on the output device. Then, the layout() method or
|
|
// equivalent will be invoked.
|
|
|
|
|
|
// PAINTING
|
|
|
|
static bool _debugDoingPaint = false;
|
|
static bool get debugDoingPaint => _debugDoingPaint;
|
|
bool _debugDoingThisPaint = false;
|
|
bool get debugDoingThisPaint => _debugDoingThisPaint;
|
|
static RenderObject _debugActivePaint = null;
|
|
static RenderObject get debugActivePaint => _debugActivePaint;
|
|
|
|
static List<RenderObject> _nodesNeedingPaint = <RenderObject>[];
|
|
static List<RenderObject> _nodesNeedingCompositingBitsUpdate = <RenderObject>[];
|
|
|
|
/// Whether this render object paints using a composited layer.
|
|
///
|
|
/// Override this in subclasses to indicate that instances of your class need
|
|
/// to have their own compositing layer. For example, videos should return
|
|
/// true if they use hardware decoders.
|
|
///
|
|
/// Note: This getter must not change value over the lifetime of this object.
|
|
bool get hasLayer => false;
|
|
|
|
ContainerLayer _layer;
|
|
/// The compositing layer that this render object uses to paint.
|
|
///
|
|
/// Call only when [hasLayer] is true.
|
|
ContainerLayer get layer {
|
|
assert(hasLayer);
|
|
assert(!_needsPaint);
|
|
return _layer;
|
|
}
|
|
|
|
bool _needsCompositingBitsUpdate = false; // set to true when a child is added
|
|
/// Mark the compositing state for this render object as dirty.
|
|
///
|
|
/// When the subtree is mutated, we need to recompute our
|
|
/// [needsCompositing] bit, and some of our ancestors need to do the
|
|
/// same (in case ours changed in a way that will change theirs). To
|
|
/// this end, [adoptChild] and [dropChild] call this method, and, as
|
|
/// necessary, this method calls the parent's, etc, walking up the
|
|
/// tree to mark all the nodes that need updating.
|
|
///
|
|
/// This method does not schedule a rendering frame, because since
|
|
/// it cannot be the case that _only_ the compositing bits changed,
|
|
/// something else will have scheduled a frame for us.
|
|
void _markNeedsCompositingBitsUpdate() {
|
|
if (_needsCompositingBitsUpdate)
|
|
return;
|
|
_needsCompositingBitsUpdate = true;
|
|
if (parent is RenderObject) {
|
|
final RenderObject parent = this.parent;
|
|
if (parent._needsCompositingBitsUpdate)
|
|
return;
|
|
if (!hasLayer && !parent.hasLayer) {
|
|
parent._markNeedsCompositingBitsUpdate();
|
|
return;
|
|
}
|
|
}
|
|
assert(() {
|
|
final AbstractNode parent = this.parent;
|
|
if (parent is RenderObject)
|
|
return parent._needsCompositing;
|
|
return true;
|
|
});
|
|
// parent is fine (or there isn't one), but we are dirty
|
|
_nodesNeedingCompositingBitsUpdate.add(this);
|
|
}
|
|
|
|
/// Updates the [needsCompositing] bits.
|
|
///
|
|
/// Called as part of the rendering pipeline after [flushLayout] and before
|
|
/// [flushPaint].
|
|
static void flushCompositingBits() {
|
|
Timeline.startSync('Compositing Bits');
|
|
_nodesNeedingCompositingBitsUpdate.sort((RenderObject a, RenderObject b) => a.depth - b.depth);
|
|
for (RenderObject node in _nodesNeedingCompositingBitsUpdate) {
|
|
if (node.attached)
|
|
node._updateCompositingBits();
|
|
}
|
|
_nodesNeedingCompositingBitsUpdate.clear();
|
|
Timeline.finishSync();
|
|
}
|
|
|
|
bool _needsCompositing; // initialised in the constructor
|
|
/// Whether we or one of our descendants has a compositing layer.
|
|
///
|
|
/// Only legal to call after [flushLayout] and [flushCompositingBits] have
|
|
/// been called.
|
|
bool get needsCompositing {
|
|
assert(!_needsCompositingBitsUpdate); // make sure we don't use this bit when it is dirty
|
|
return _needsCompositing;
|
|
}
|
|
|
|
void _updateCompositingBits() {
|
|
if (!_needsCompositingBitsUpdate)
|
|
return;
|
|
bool oldNeedsCompositing = _needsCompositing;
|
|
visitChildren((RenderObject child) {
|
|
child._updateCompositingBits();
|
|
if (child.needsCompositing)
|
|
_needsCompositing = true;
|
|
});
|
|
if (hasLayer)
|
|
_needsCompositing = true;
|
|
if (oldNeedsCompositing != _needsCompositing)
|
|
markNeedsPaint();
|
|
_needsCompositingBitsUpdate = false;
|
|
}
|
|
|
|
bool _needsPaint = true;
|
|
/// The visual appearance of this render object has changed since it last painted.
|
|
bool get needsPaint => _needsPaint;
|
|
|
|
/// Mark this render object as having changed its visual appearance.
|
|
///
|
|
/// Rather than eagerly updating this render object's display list
|
|
/// in response to writes, we instead mark the the render object as needing to
|
|
/// paint, which schedules a visual update. As part of the visual update, the
|
|
/// rendering pipeline will give this render object an opportunity to update
|
|
/// its display list.
|
|
///
|
|
/// This mechanism batches the painting work so that multiple sequential
|
|
/// writes are coalesced, removing redundant computation.
|
|
void markNeedsPaint() {
|
|
assert(!debugDoingPaint);
|
|
if (!attached)
|
|
return; // Don't try painting things that aren't in the hierarchy
|
|
if (_needsPaint)
|
|
return;
|
|
_needsPaint = true;
|
|
if (hasLayer) {
|
|
// If we always have our own layer, then we can just repaint
|
|
// ourselves without involving any other nodes.
|
|
assert(_layer != null);
|
|
_nodesNeedingPaint.add(this);
|
|
Scheduler.instance.ensureVisualUpdate();
|
|
} else if (parent is RenderObject) {
|
|
// We don't have our own layer; one of our ancestors will take
|
|
// care of updating the layer we're in and when they do that
|
|
// we'll get our paint() method called.
|
|
assert(_layer == null);
|
|
final RenderObject parent = this.parent;
|
|
parent.markNeedsPaint();
|
|
assert(parent == this.parent);
|
|
} else {
|
|
// If we're the root of the render tree (probably a RenderView),
|
|
// then we have to paint ourselves, since nobody else can paint
|
|
// us. We don't add ourselves to _nodesNeedingPaint in this
|
|
// case, because the root is always told to paint regardless.
|
|
Scheduler.instance.ensureVisualUpdate();
|
|
}
|
|
}
|
|
|
|
/// Update the display lists for all render objects.
|
|
///
|
|
/// This function is one of the core stages of the rendering pipeline.
|
|
/// Painting occurs after layout and before the scene is recomposited so that
|
|
/// scene is composited with up-to-date display lists for every render object.
|
|
///
|
|
/// See [FlutterBinding] for an example of how this function is used.
|
|
static void flushPaint() {
|
|
Timeline.startSync('Paint');
|
|
_debugDoingPaint = true;
|
|
try {
|
|
List<RenderObject> dirtyNodes = _nodesNeedingPaint;
|
|
_nodesNeedingPaint = <RenderObject>[];
|
|
// Sort the dirty nodes in reverse order (deepest first).
|
|
for (RenderObject node in dirtyNodes..sort((RenderObject a, RenderObject b) => b.depth - a.depth)) {
|
|
assert(node._needsPaint);
|
|
if (node.attached)
|
|
PaintingContext.repaintCompositedChild(node);
|
|
};
|
|
assert(_nodesNeedingPaint.length == 0);
|
|
} finally {
|
|
_debugDoingPaint = false;
|
|
Timeline.finishSync();
|
|
}
|
|
}
|
|
|
|
/// Bootstrap the rendering pipeline by scheduling the very first paint.
|
|
///
|
|
/// Requires that this render object is attached, is the root of the render
|
|
/// tree, and has a composited layer.
|
|
///
|
|
/// See [RenderView] for an example of how this function is used.
|
|
void scheduleInitialPaint(ContainerLayer rootLayer) {
|
|
assert(attached);
|
|
assert(parent is! RenderObject);
|
|
assert(!_debugDoingPaint);
|
|
assert(hasLayer);
|
|
assert(_layer == null);
|
|
_layer = rootLayer;
|
|
assert(_needsPaint);
|
|
_nodesNeedingPaint.add(this);
|
|
}
|
|
void _paintWithContext(PaintingContext context, Offset offset) {
|
|
assert(!_debugDoingThisPaint);
|
|
assert(!_needsLayout);
|
|
assert(!_needsCompositingBitsUpdate);
|
|
RenderObject debugLastActivePaint;
|
|
assert(() {
|
|
_debugDoingThisPaint = true;
|
|
debugLastActivePaint = _debugActivePaint;
|
|
_debugActivePaint = this;
|
|
assert(!hasLayer || _layer != null);
|
|
return true;
|
|
});
|
|
_needsPaint = false;
|
|
try {
|
|
paint(context, offset);
|
|
assert(!_needsLayout); // check that the paint() method didn't mark us dirty again
|
|
assert(!_needsPaint); // check that the paint() method didn't mark us dirty again
|
|
} catch (e, stack) {
|
|
_debugReportException('paint', e, stack);
|
|
}
|
|
assert(() {
|
|
debugPaint(context, offset);
|
|
_debugActivePaint = debugLastActivePaint;
|
|
_debugDoingThisPaint = false;
|
|
return true;
|
|
});
|
|
}
|
|
|
|
/// The bounds within which this render object will paint.
|
|
///
|
|
/// A render object is permitted to paint outside the region it occupies
|
|
/// during layout but is not permitted to paint outside these paints bounds.
|
|
/// These paint bounds are used to construct memory-efficient composited
|
|
/// layers, which means attempting to paint outside these bounds can attempt
|
|
/// to write to pixels that do not exist in this render object's composited
|
|
/// layer.
|
|
Rect get paintBounds;
|
|
|
|
/// Override this function to paint debugging information.
|
|
void debugPaint(PaintingContext context, Offset offset) { }
|
|
|
|
/// Paint this render object into the given context at the given offset.
|
|
///
|
|
/// Subclasses should override this function to provide a visual appearance
|
|
/// for themselves. The render object's local coordinate system is
|
|
/// axis-aligned with the coordinate system of the context's canvas and the
|
|
/// render object's local origin (i.e, x=0 and y=0) is placed at the given
|
|
/// offset in the context's canvas.
|
|
///
|
|
/// Do not call this function directly. If you wish to paint yourself, call
|
|
/// [markNeedsPaint] instead to schedule a call to this function. If you wish
|
|
/// to paint one of your children, call one of the paint child functions on
|
|
/// the given context, such as [paintChild] or [paintChildWithClipRect].
|
|
///
|
|
/// When painting one of your children (via a paint child function on the
|
|
/// given context), the current canvas held by the context might change
|
|
/// because draw operations before and after painting children might need to
|
|
/// be recorded on separate compositing layers.
|
|
void paint(PaintingContext context, Offset offset) { }
|
|
|
|
/// Applies the transform that would be applied when painting the given child
|
|
/// to the given matrix.
|
|
///
|
|
/// Used by coordinate conversion functions to translate coordinates local to
|
|
/// one render object into coordinates local to another render object.
|
|
void applyPaintTransform(RenderObject child, Matrix4 transform) {
|
|
assert(child.parent == this);
|
|
}
|
|
|
|
|
|
// EVENTS
|
|
|
|
/// Override this function to handle pointer events that hit this render object.
|
|
void handleEvent(PointerEvent event, HitTestEntry entry) { }
|
|
|
|
|
|
// HIT TESTING
|
|
|
|
// RenderObject subclasses are expected to have a method like the
|
|
// following (with the signature being whatever passes for coordinates
|
|
// for this particular class):
|
|
// bool hitTest(HitTestResult result, { Point position }) {
|
|
// // If (x,y) is not inside this node, then return false. (You
|
|
// // can assume that the given coordinate is inside your
|
|
// // dimensions. You only need to check this if you're an
|
|
// // irregular shape, e.g. if you have a hole.)
|
|
// // Otherwise:
|
|
// // For each child that intersects x,y, in z-order starting from the top,
|
|
// // call hitTest() for that child, passing it /result/, and the coordinates
|
|
// // converted to the child's coordinate origin, and stop at the first child
|
|
// // that returns true.
|
|
// // Then, add yourself to /result/, and return true.
|
|
// }
|
|
// You must not add yourself to /result/ if you return false.
|
|
|
|
|
|
/// Returns a human understandable name.
|
|
String toString() {
|
|
String header = '$runtimeType';
|
|
if (_relayoutSubtreeRoot != null && _relayoutSubtreeRoot != this) {
|
|
int count = 1;
|
|
RenderObject target = parent;
|
|
while (target != null && target != _relayoutSubtreeRoot) {
|
|
target = target.parent;
|
|
count += 1;
|
|
}
|
|
header += ' relayoutSubtreeRoot=up$count';
|
|
}
|
|
if (_needsLayout)
|
|
header += ' NEEDS-LAYOUT';
|
|
if (!attached)
|
|
header += ' DETACHED';
|
|
return header;
|
|
}
|
|
|
|
/// Returns a description of the tree rooted at this node.
|
|
/// If the prefix argument is provided, then every line in the output
|
|
/// will be prefixed by that string.
|
|
String toStringDeep([String prefixLineOne = '', String prefixOtherLines = '']) {
|
|
RenderObject debugPreviousActiveLayout = _debugActiveLayout;
|
|
_debugActiveLayout = null;
|
|
String result = '$prefixLineOne$this\n';
|
|
final String childrenDescription = debugDescribeChildren(prefixOtherLines);
|
|
final String settingsPrefix = childrenDescription != '' ? '$prefixOtherLines \u2502 ' : '$prefixOtherLines ';
|
|
List<String> settings = <String>[];
|
|
debugDescribeSettings(settings);
|
|
result += settings.map((String setting) => "$settingsPrefix$setting\n").join();
|
|
if (childrenDescription == '')
|
|
result += '$prefixOtherLines\n';
|
|
result += childrenDescription;
|
|
_debugActiveLayout = debugPreviousActiveLayout;
|
|
return result;
|
|
}
|
|
|
|
/// Returns a list of strings describing the current node's fields, one field
|
|
/// per string. Subclasses should override this to have their information
|
|
/// included in toStringDeep().
|
|
void debugDescribeSettings(List<String> settings) {
|
|
if (debugOwner != null)
|
|
settings.add('owner: $debugOwner');
|
|
settings.add('parentData: $parentData');
|
|
settings.add('constraints: $constraints');
|
|
}
|
|
|
|
/// Returns a string describing the current node's descendants. Each line of
|
|
/// the subtree in the output should be indented by the prefix argument.
|
|
String debugDescribeChildren(String prefix) => '';
|
|
|
|
}
|
|
|
|
/// Obsolete function that will be removed eventually.
|
|
double clamp({ double min: 0.0, double value: 0.0, double max: double.INFINITY }) {
|
|
assert(min != null);
|
|
assert(value != null);
|
|
assert(max != null);
|
|
return math.max(min, math.min(max, value));
|
|
}
|
|
|
|
|
|
/// Generic mixin for render objects with one child.
|
|
///
|
|
/// Provides a child model for a render object subclass that has a unique child.
|
|
abstract class RenderObjectWithChildMixin<ChildType extends RenderObject> implements RenderObject {
|
|
ChildType _child;
|
|
/// The render object's unique child
|
|
ChildType get child => _child;
|
|
void set child (ChildType value) {
|
|
if (_child != null)
|
|
dropChild(_child);
|
|
_child = value;
|
|
if (_child != null)
|
|
adoptChild(_child);
|
|
}
|
|
void attach() {
|
|
super.attach();
|
|
if (_child != null)
|
|
_child.attach();
|
|
}
|
|
void detach() {
|
|
super.detach();
|
|
if (_child != null)
|
|
_child.detach();
|
|
}
|
|
void visitChildren(RenderObjectVisitor visitor) {
|
|
if (_child != null)
|
|
visitor(_child);
|
|
}
|
|
String debugDescribeChildren(String prefix) {
|
|
if (child != null)
|
|
return '$prefix \u2502\n${child.toStringDeep('$prefix \u2514\u2500child: ', '$prefix ')}';
|
|
return '';
|
|
}
|
|
}
|
|
|
|
/// Parent data to support a doubly-linked list of children.
|
|
abstract class ContainerParentDataMixin<ChildType extends RenderObject> implements ParentData {
|
|
/// The previous sibling in the parent's child list.
|
|
ChildType previousSibling;
|
|
/// The next sibling in the parent's child list.
|
|
ChildType nextSibling;
|
|
|
|
/// Clear the sibling pointers.
|
|
void detach() {
|
|
super.detach();
|
|
if (previousSibling != null) {
|
|
final ContainerParentDataMixin<ChildType> previousSiblingParentData = previousSibling.parentData;
|
|
assert(previousSibling != this);
|
|
assert(previousSiblingParentData.nextSibling == this);
|
|
previousSiblingParentData.nextSibling = nextSibling;
|
|
}
|
|
if (nextSibling != null) {
|
|
final ContainerParentDataMixin<ChildType> nextSiblingParentData = nextSibling.parentData;
|
|
assert(nextSibling != this);
|
|
assert(nextSiblingParentData.previousSibling == this);
|
|
nextSiblingParentData.previousSibling = previousSibling;
|
|
}
|
|
previousSibling = null;
|
|
nextSibling = null;
|
|
}
|
|
}
|
|
|
|
/// Generic mixin for render objects with a list of children.
|
|
///
|
|
/// Provides a child model for a render object subclass that has a doubly-linked
|
|
/// list of children.
|
|
abstract class ContainerRenderObjectMixin<ChildType extends RenderObject, ParentDataType extends ContainerParentDataMixin<ChildType>> implements RenderObject {
|
|
|
|
bool _debugUltimatePreviousSiblingOf(ChildType child, { ChildType equals }) {
|
|
ParentDataType childParentData = child.parentData;
|
|
while (childParentData.previousSibling != null) {
|
|
assert(childParentData.previousSibling != child);
|
|
child = childParentData.previousSibling;
|
|
childParentData = child.parentData;
|
|
}
|
|
return child == equals;
|
|
}
|
|
bool _debugUltimateNextSiblingOf(ChildType child, { ChildType equals }) {
|
|
ParentDataType childParentData = child.parentData;
|
|
while (childParentData.nextSibling != null) {
|
|
assert(childParentData.nextSibling != child);
|
|
child = childParentData.nextSibling;
|
|
childParentData = child.parentData;
|
|
}
|
|
return child == equals;
|
|
}
|
|
|
|
int _childCount = 0;
|
|
/// The number of children.
|
|
int get childCount => _childCount;
|
|
|
|
ChildType _firstChild;
|
|
ChildType _lastChild;
|
|
void _addToChildList(ChildType child, { ChildType before }) {
|
|
final ParentDataType childParentData = child.parentData;
|
|
assert(childParentData.nextSibling == null);
|
|
assert(childParentData.previousSibling == null);
|
|
_childCount += 1;
|
|
assert(_childCount > 0);
|
|
if (before == null) {
|
|
// append at the end (_lastChild)
|
|
childParentData.previousSibling = _lastChild;
|
|
if (_lastChild != null) {
|
|
final ParentDataType _lastChildParentData = _lastChild.parentData;
|
|
_lastChildParentData.nextSibling = child;
|
|
}
|
|
_lastChild = child;
|
|
if (_firstChild == null)
|
|
_firstChild = child;
|
|
} else {
|
|
assert(_firstChild != null);
|
|
assert(_lastChild != null);
|
|
assert(_debugUltimatePreviousSiblingOf(before, equals: _firstChild));
|
|
assert(_debugUltimateNextSiblingOf(before, equals: _lastChild));
|
|
final ParentDataType beforeParentData = before.parentData;
|
|
if (beforeParentData.previousSibling == null) {
|
|
// insert at the start (_firstChild); we'll end up with two or more children
|
|
assert(before == _firstChild);
|
|
childParentData.nextSibling = before;
|
|
beforeParentData.previousSibling = child;
|
|
_firstChild = child;
|
|
} else {
|
|
// insert in the middle; we'll end up with three or more children
|
|
// set up links from child to siblings
|
|
childParentData.previousSibling = beforeParentData.previousSibling;
|
|
childParentData.nextSibling = before;
|
|
// set up links from siblings to child
|
|
final ParentDataType childPreviousSiblingParentData = childParentData.previousSibling.parentData;
|
|
final ParentDataType childNextSiblingParentData = childParentData.nextSibling.parentData;
|
|
childPreviousSiblingParentData.nextSibling = child;
|
|
childNextSiblingParentData.previousSibling = child;
|
|
assert(beforeParentData.previousSibling == child);
|
|
}
|
|
}
|
|
}
|
|
/// Insert child into this render object's child list before the given child.
|
|
///
|
|
/// To insert a child at the end of the child list, omit the before parameter.
|
|
void add(ChildType child, { ChildType before }) {
|
|
assert(child != this);
|
|
assert(before != this);
|
|
assert(child != before);
|
|
assert(child != _firstChild);
|
|
assert(child != _lastChild);
|
|
adoptChild(child);
|
|
_addToChildList(child, before: before);
|
|
}
|
|
|
|
/// Add all the children to the end of this render object's child list.
|
|
void addAll(List<ChildType> children) {
|
|
if (children != null)
|
|
for (ChildType child in children)
|
|
add(child);
|
|
}
|
|
|
|
void _removeFromChildList(ChildType child) {
|
|
final ParentDataType childParentData = child.parentData;
|
|
assert(_debugUltimatePreviousSiblingOf(child, equals: _firstChild));
|
|
assert(_debugUltimateNextSiblingOf(child, equals: _lastChild));
|
|
assert(_childCount >= 0);
|
|
if (childParentData.previousSibling == null) {
|
|
assert(_firstChild == child);
|
|
_firstChild = childParentData.nextSibling;
|
|
} else {
|
|
final ParentDataType childPreviousSiblingParentData = childParentData.previousSibling.parentData;
|
|
childPreviousSiblingParentData.nextSibling = childParentData.nextSibling;
|
|
}
|
|
if (childParentData.nextSibling == null) {
|
|
assert(_lastChild == child);
|
|
_lastChild = childParentData.previousSibling;
|
|
} else {
|
|
final ParentDataType childNextSiblingParentData = childParentData.nextSibling.parentData;
|
|
childNextSiblingParentData.previousSibling = childParentData.previousSibling;
|
|
}
|
|
childParentData.previousSibling = null;
|
|
childParentData.nextSibling = null;
|
|
_childCount -= 1;
|
|
}
|
|
|
|
/// Remove this child from the child list.
|
|
///
|
|
/// Requires the child to be present in the child list.
|
|
void remove(ChildType child) {
|
|
_removeFromChildList(child);
|
|
dropChild(child);
|
|
}
|
|
|
|
/// Remove all their children from this render object's child list.
|
|
///
|
|
/// More efficient than removing them individually.
|
|
void removeAll() {
|
|
ChildType child = _firstChild;
|
|
while (child != null) {
|
|
final ParentDataType childParentData = child.parentData;
|
|
ChildType next = childParentData.nextSibling;
|
|
childParentData.previousSibling = null;
|
|
childParentData.nextSibling = null;
|
|
dropChild(child);
|
|
child = next;
|
|
}
|
|
_firstChild = null;
|
|
_lastChild = null;
|
|
_childCount = 0;
|
|
}
|
|
|
|
/// Move this child in the child list to be before the given child.
|
|
///
|
|
/// More efficient than removing and re-adding the child. Requires the child
|
|
/// to already be in the child list at some position. Pass null for before to
|
|
/// move the child to the end of the child list.
|
|
void move(ChildType child, { ChildType before }) {
|
|
assert(child != this);
|
|
assert(before != this);
|
|
assert(child != before);
|
|
assert(child.parent == this);
|
|
final ParentDataType childParentData = child.parentData;
|
|
if (childParentData.nextSibling == before)
|
|
return;
|
|
_removeFromChildList(child);
|
|
_addToChildList(child, before: before);
|
|
}
|
|
|
|
void attach() {
|
|
super.attach();
|
|
ChildType child = _firstChild;
|
|
while (child != null) {
|
|
child.attach();
|
|
final ParentDataType childParentData = child.parentData;
|
|
child = childParentData.nextSibling;
|
|
}
|
|
}
|
|
|
|
void detach() {
|
|
super.detach();
|
|
ChildType child = _firstChild;
|
|
while (child != null) {
|
|
child.detach();
|
|
final ParentDataType childParentData = child.parentData;
|
|
child = childParentData.nextSibling;
|
|
}
|
|
}
|
|
|
|
void redepthChildren() {
|
|
ChildType child = _firstChild;
|
|
while (child != null) {
|
|
redepthChild(child);
|
|
final ParentDataType childParentData = child.parentData;
|
|
child = childParentData.nextSibling;
|
|
}
|
|
}
|
|
|
|
void visitChildren(RenderObjectVisitor visitor) {
|
|
ChildType child = _firstChild;
|
|
while (child != null) {
|
|
visitor(child);
|
|
final ParentDataType childParentData = child.parentData;
|
|
child = childParentData.nextSibling;
|
|
}
|
|
}
|
|
|
|
/// The first child in the child list.
|
|
ChildType get firstChild => _firstChild;
|
|
|
|
/// The last child in the child list.
|
|
ChildType get lastChild => _lastChild;
|
|
|
|
/// The next child after the given child in the child list.
|
|
ChildType childAfter(ChildType child) {
|
|
final ParentDataType childParentData = child.parentData;
|
|
return childParentData.nextSibling;
|
|
}
|
|
|
|
String debugDescribeChildren(String prefix) {
|
|
String result = '$prefix \u2502\n';
|
|
if (_firstChild != null) {
|
|
ChildType child = _firstChild;
|
|
int count = 1;
|
|
while (child != _lastChild) {
|
|
result += '${child.toStringDeep("$prefix \u251C\u2500child $count: ", "$prefix \u2502")}';
|
|
count += 1;
|
|
final ParentDataType childParentData = child.parentData;
|
|
child = childParentData.nextSibling;
|
|
}
|
|
if (child != null) {
|
|
assert(child == _lastChild);
|
|
result += '${child.toStringDeep("$prefix \u2514\u2500child $count: ", "$prefix ")}';
|
|
}
|
|
}
|
|
return result;
|
|
}
|
|
}
|