如果元素设置为culling在切换页面时会出现不渲染的情况

[xiaotusi]

问题描述

前置条件

• 使用了Angular页面缓存
• 使用了ResizeObserver监听zrender宿主dom尺寸，如果尺寸发生变化则调用zrenderIns.resize()
• 元素设置了culling: true
• 路由A: zrender绘制页面，路由B: 常规配置页面

复现步骤

2024-10-01.08.12.31.mov

1. 第一次页面加载路由A，渲染没有问题
2. 切换至路由B
3. 切回路由A
4. 绘制元素消失

问题分析

refresh执行中会判断元素如果设置为culling则会判断是否在可视区域中，不在则不会渲染。而之前切换页面时会导致zrender宿主dom的尺寸变为长宽为0, 所以无论如何判断元素都不会渲染
而调用resize函数后, 源码确实会计算当前视窗尺寸但是没有设置_width 和 _height 这两个私有属性

zrender/src/canvas/Painter.ts

Lines 870 to 884 in 247e119

	if (this._width !== width || height !== this._height) {
	domRoot.style.width = width + 'px';
	domRoot.style.height = height + 'px';
	for (let id in this._layers) {
	if (this._layers.hasOwnProperty(id)) {
	this._layers[id].resize(width, height);
	}
	}
	this.refresh(true);
	}
	this._width = width;
	this._height = height;

这段代码会使用_width和_height

zrender/src/canvas/Painter.ts

Lines 413 to 440 in 247e119

	const repaint = (repaintRect?: BoundingRect) => {
	const scope: BrushScope = {
	inHover: false,
	allClipped: false,
	prevEl: null,
	viewWidth: this._width,
	viewHeight: this._height
	};
	for (i = start; i < layer.__endIndex; i++) {
	const el = list[i];
	if (el.__inHover) {
	needsRefreshHover = true;
	}
	this._doPaintEl(el, layer, useDirtyRect, repaintRect, scope, i === layer.__endIndex - 1);
	if (useTimer) {
	// Date.now can be executed in 13,025,305 ops/second.
	const dTime = Date.now() - startTime;
	// Give 15 millisecond to draw.
	// The rest elements will be drawn in the next frame.
	if (dTime > 15) {
	break;
	}
	}
	}

Line 215 永真

zrender/src/graphic/Displayable.ts

Lines 208 to 223 in 247e119

	if (
	this.ignore
	// Ignore invisible element
	|| this.invisible
	// Ignore transparent element
	|| this.style.opacity === 0
	// Ignore culled element
	|| (this.culling
	&& isDisplayableCulled(this, viewWidth, viewHeight)
	)
	// Ignore scale 0 element, in some environment like node-canvas
	// Draw a scale 0 element can cause all following draw wrong
	// And setTransform with scale 0 will cause set back transform failed.
	|| (m && !m[0] && !m[3])
	) {
	return false;

可能方案

前置

zrender/src/canvas/Painter.ts

Lines 883 to 884 in 247e119

	this._width = width;
	this._height = height;

临时方案

再调用一遍refrsh(true)进行全部刷新 😭
(this.zrenderIns.painter.refresh as EtSafeAny)(true); Ts 语法还报错 可以的话这玩意也修复下

[Ovilia]

切换页面应该要 dispose 掉的，回到该页面重新初始化