Canvas Pixel Manipulation

JavaScript performance comparison

Revision 72 of this test case created by orwellophile

Preparation code

<canvas id="canvas" height="800" width="256"></canvas>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>
<script>
var canvas = document.getElementById('canvas');
var canvasWidth = canvas.width = $('.user-output').width()
var canvasHeight = canvas.height = $('.user-output').height()
var ctx = canvas.getContext('2d');
var imageData = ctx.getImageData(0, 0, canvasWidth, canvasHeight);

var data = imageData.data;

var counter = 0;



var buf = new ArrayBuffer(imageData.data.length);
var buf8 = new Uint8ClampedArray(buf);
var data32 = new Uint32Array(buf);
</script>
      
<script>
Benchmark.prototype.teardown = function() {
  counter++;

};
</script>

Preparation code output

<canvas id="canvas" height="800" width="256"></canvas>

Test runner

Warning! For accurate results, please disable Firebug before running the tests. (Why?)

Java applet disabled.

Testing in CCBot 2.0.0 / Other 0.0.0
Test Ops/sec
8-bit Pixel Manipulation
for (var y = 0; y < canvasHeight; ++y) {
    for (var x = 0; x < canvasWidth; ++x) {
        var index = (y * canvasWidth + x) * 4;

        var value = counter + (x * y) & 0xff;

        data[index]   = value;    // red
        data[++index] = value;    // green
        data[++index] = value;    // blue
        data[++index] = 255;      // alpha
    }
}

ctx.putImageData(imageData, 0, 0);
pending…
32-bit Pixel Manipulation
for (var y = 0; y < canvasHeight; ++y) {
    for (var x = 0; x < canvasWidth; ++x) {
        var value = counter + (x * y) & 0xff;

        data32[y * canvasWidth + x] =
            (255   << 24) |    // alpha
            (value << 16) |    // blue
            (value <<  8) |    // green
             value;            // red
    }
}

imageData.data.set(buf8);
ctx.putImageData(imageData, 0, 0);
pending…

Compare results of other browsers

Revisions

You can edit these tests or add even more tests to this page by appending /edit to the URL.

0 Comments