requestanimationframe

window.requestAnimationFrame() 注意：若你想在浏览器下次重绘之前继续更新下一帧动画，那么回调函数自身必须再次调用 window.requestAnimationFrame() 当你准备更新动画时你应该调用此方法。这将使浏览器在下一次重绘之前调用你传入给该方法的动画函数(即你的回调函数)。回调函数执行次数通常是每秒60次，但在大多数遵循W3C建议的浏览器中，回调函数执行次数通常与浏览器屏幕刷新次数相匹配。为了提高性能和电池寿命，因此在大多数浏览器里，当 requestAnimationFrame() requestAnimationFrame() 回调函数会被传入参数， requestAnimationFrame() window.requestAnimationFrame(callback); callback 下一次重绘之前更新动画帧所调用的函数(即上面所说的回调函数)。该回调函数会被传入参数，该参数与的返回值相同，它表示 requestAnimationFrame() long window.cancelAnimationFrame() 范例 var start = null; var element = document.getElementById('SomeElementYouWantToAnimate'); element.style

/** ** 得到浏览器每秒帧数fps ** ** @Date Mar 13 2013 **/ var showFPS = (function(){ var requestAnimationFrame = window.requestAnimationFrame || //Chromium window.webkitRequestAnimationFrame || //Webkit window.mozRequestAnimationFrame || //Mozilla Geko window.oRequestAnimationFrame || //Opera Presto window.msRequestAnimationFrame || //IE Trident? function(callback) { //Fallback function window.setTimeout(callback, 1000/60); }; var e,pe,pid,fps,last,offset,step,appendFps; fps = 0; last = Date.now(); step = function(){ offset = Date.now() - last; fps += 1; if( offset >= 1000 ){ last += offset; appendFps

I am making a script that auto generates planets see codepen for example . But the problem I have is that i want to make it less pixelated and I am having some problems doing that if i make the tiles 70 * 70 and tile size to 10 * 10 pixels it works fine. But i want to have it set to something like tiles 360 * 360 and size to 1 or 2 pixels. But when I try to do that I get maximum call stack error. So I tried to use the requestAnimationFrame but then it take ages to load is there a way to speed up the process? var tileNum = 0; var tiles; var colorsLand; var colorsWater; var size = 360; var

本文转载于: 专业的前端网站 ➞ Touch开发必须知道的事儿 持续跟大家分享一些最新的前端技术进展、开发最佳实践，好了，不多说了，言归正传，今天跟大家分享Touch开发的一些细节问题，希望可以对相关开发人员有所帮助。 常见问题1：判断设备支持touch就只用touch 判断设备支持touch就只用touch会有问题，因为像Chrome pixel这样的设备同时支持触屏和鼠标,如果这样判断就会让Chrome pixel的鼠标失效，而仅仅是因为它同时支持触屏 解决方案：两个都监听，然后使用preventDefault来避免多次执行 element.addEventListener('touchstart', activate); element.addEventListener('mousedown', activate); function activate(event) { ... event.preventDefault(); } 常见问题2：Touch event Target的特殊性 MouseEvent的target始终指向cursor所指向的元素，TouchEvent的target只是指向touch start的时候所接触的元素，即使这个dom被删除掉，这样如果当你在touch move某些元素，而其中某个dom有可能在移动中被删除就会出现很诡异的问题 解决方案

I am using HTML canvas to draw multiple squares. I have 2 functions: 1) draw a square and 2) draw multiple squares inside a loop. Now I want to animate these squares using requestAnimationFrame to draw these square one at a time. How can I achieve this. Here is a jsFiddle var canvas = document.getElementById('canvas'), ctx = canvas.getContext('2d'); function rect(x, y, w, h) { ctx.beginPath(); ctx.rect(x, y, w, h); ctx.stroke(); } function drawRect(number, size) { for (var i = 0; i <= number; i++) { rect(i * size, i * size, (i * size) * 2, (i * size) * 2); } } drawRect(10, 5); You can do

方法1: 使用setTimeout(); function sayHi(){ alert("Hi."); } setTimeout(sayHi, 2000); 方法2: 使用window.requestAnimationFrame(); var element = document.getElementById('animate'); element.style.position = 'absolute'; var start = null; function step(timestamp) { if (!start) start = timestamp; var progress = timestamp - start; // 元素不断向左移，最大不超过200像素 element.style.left = Math.min(progress / 10, 200) + 'px'; // 如果距离第一次执行不超过 2000 毫秒， // 就继续执行动画 if (progress < 2000) { window.requestAnimationFrame(step); } } window.requestAnimationFrame(step); 两者区别: setTimeout()需要手动设置延迟时间, 而requestAnimationFrame(

The function to render my canvas is a prototyped method of a class, like this: Engine.prototype.renderCameras = function() { console.log('render ok'); } When I try to run this code directly, it works fine: engine.renderCameras() >>> render ok When I try to run it using requestAnimationFrame, in either Chrome or Firefox, I get this: window.requestAnimFrame(engine.renderCameras()) >>> render ok >>> Error: Component returned failure code: 0x80570009 (NS_ERROR_XPC_BAD_CONVERT_JS) [nsIDOMWindow.mozRequestAnimationFrame] It runs, but it always throws an error. That's not cool. When I try to run it