cec/demo-web/canvas.html at master · hongru/cec · GitHub

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<!DOCTYPE html>
<canvas id="canvas" width="200" height="200"></canvas>
<img id="img" src="http://gtms01.alicdn.com/tps/i1/T1TicJFgVcXXab91rk-461-457.png" />

<script>
    var canvas = document.getElementById('canvas'),
        ctx = canvas.getContext('2d'),
        img = document.getElementById('img'),
        tmp = document.createElement('canvas'),
        _ctx = tmp.getContext('2d');


    onload = function () {

        tmp.width = img.width;
        tmp.height = img.height;
        _ctx.drawImage(img, 0, 0);
console.time('cvs')
        for(var i = 0;i < 1000; i ++) {
            ctx.drawImage(tmp, 0, 0);
        }
        console.timeEnd('cvs')
        console.time('img')
        for(var i = 0;i < 1000; i ++) {
            ctx.drawImage(img, 0, 0);
        }
        console.timeEnd('img')


    }
</script>