requestanimationframe

Paul Irish has a post called requestAnimationFrame for Smart Animating . Now Paul is a smart guy - and I'm just trying to understand the scope of the application of this idea. He says to do HTML5 animation - you should use a requestAnimationFrame shim like this: // shim layer with setTimeout fallback window.requestAnimFrame = (function(){ return window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || function( callback ){ window.setTimeout(callback, 1000 / 60); }; })(); // usage: // instead of setInterval(render, 16) .... (function animloop(){

I've been experimenting with jank-free rendering of complex scenes on HTML5 canvas. The idea is to split rendering into multiple batches with each batch taking a maximum of, say 12 ms, so that the concurrently running animations (very cheap to execute) are not interrupted. Conceptually, batch-rendering is implemented like this: function draw(ctx) { var deadline = window.performance.now() + 12; // inaccurate, but enough for the example var i = 0; requestAnimationFrame(function drawWithDeadline() { for (; i < itemsToRender.length; i++) { if (window.performance.now() >= deadline) {

While watching Google IO17, I learnt about the double requestAnimationFrame method but i can't really wrap my head around it maybe because i hardly involve myself in animation on the web. However, i think it would nice to know how it works and when to double things up as in the case of Twitter's tab example laid out by Addy Osmani. Thanks! Because of the bug introduced in Chrome and some others, we have to use double requestAnimationFrame whenever we find ourselves toggling classes or performing other CSS animations that requires RAF to fire after an action is performed. It's kinda like an

Identification: I'm looking at all possible solutions for detecting when the FPS drop or the repaints/reflows stop happening in a browser due to the browser optimizing performance because an area of the document is out of view. Observation: So far most native HTML/JS solutions I have researched do not take into account the portion of the DOM, which has been obscured by other pieces of the page, or DOM which is below the fold. While sometimes content will be directly embedded in the parent document, other times it may be in a frame or iframe. Test results: mozPaintCount is an accurate

Browser reads and runs a JavaScript file, the synchronous tasks written in the file immediately become in-mid-execution task, setTimeout callbacks become macrotasks, and promise callbacks become microtasks. Everything is good. I thought I mastered the JavaScript Event Loop until I met requestAnimationFrame . @T.J. Crowder provided me with the following code snippet. const messages = []; setTimeout(() => { // Schedule a microtask Promise.resolve().then(() => { log("microtask"); }); // Schedule animation frame callback requestAnimationFrame(() => { log("requestAnimationFrame"); }); // Schedule a

I start the loop function gameLoop(){ update(); draw(); requestAnimFrame(gameLoop); } var requestAnimFrame = window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.oRequestAnimationFrame || window.msRequestAnimationFrame || function(callback) { window.setTimeout(callback, 1000 / 1); }; I can't adjust the frame rate. It is always really fast. Why can't I change it to 1 frame a second. I want to do this just for testing purposes. Do I have to clear the canvas each time? It seems to work good without clearing it. Thanks. Here is a link to a

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I know this is probably painfully basic, but i am having a tough time wrapping my head around it. class Main { constructor() { requestAnimationFrame(this.update); //fine } update(): void { requestAnimationFrame(this.update); //error, because this is window } } It appears to be the case that I need a proxy, so lets say using Jquery class Main { constructor() { this.updateProxy = $.proxy(this.update, this); requestAnimationFrame(this.updateProxy); //fine } updateProxy: () => void update(): void { requestAnimationFrame(this.updateProxy); //fine

前言 在实际工作中，我们很少会遇到一次性需要向页面中插入大量数据的情况，但是为了丰富我们的知识体系，我们有必要了解并清楚当遇到大量数据时，如何才能在不卡主页面的情况下渲染数据，以及其中背后的原理。 对于一次性插入大量数据的情况，一般有两种做法： 时间分片 虚拟列表 本文作为开篇，着重来介绍如何使用时间分片的方式来渲染大量数据，虚拟列表相关的内容，日后会持续整理。 最粗暴的做法（一次性渲染） 我们先来看看最粗暴的做法，一次性将大量数据插入到页面中： <ul id="container"></ul> 复制代码 // 记录任务开始时间 let now = Date.now(); // 插入十万条数据 const total = 100000; // 获取容器 let ul = document.getElementById('container'); // 将数据插入容器中 for (let i = 0; i < total; i++) { let li = document.createElement('li'); li.innerText = ~~(Math.random() * total) ul.appendChild(li); } console.log('JS运行时间：',Date.now() - now); setTimeout(()=>{ console.log(

使用 requestAnimationFrame 　　 与 setTimeout 相比， requestAnimationFrame 最大的优势是由系统来决定回调函数的执行时机。 如果屏幕刷新率是60Hz,那么回调函数就每16.7ms被执行一次，如果刷新率是75Hz，那么这个时间间隔就变成了1000/75=13.3ms，换句话说就是， requestAnimationFrame 的步伐跟着系统的刷新步伐走。它能保证回调函数在屏幕每一次的刷新间隔中只被执行一次，这样就不会引起丢帧现象。 我们使用 requestAnimationFrame 来进行分批渲染： //需要插入的容器 let ul = document.getElementById('container'); // 插入十万条数据 let total = 100000; // 一次插入 20 条 let once = 20; //总页数 let page = total/once //每条记录的索引 let index = 0; //循环加载数据 function loop(curTotal,curIndex){ if(curTotal <= 0){ return false; } //每页多少条 let pageCount = Math.min(curTotal , once); window