Canvas Pixel Manipulation

JavaScript performance comparison

Revision 75 of this test case created by

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>

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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;

        data[index]   = 123;    // red
        data[++index] = 0;    // green
        data[++index] = 0;    // blue
        data[++index] = 0;      // alpha
    }
}
pending…
32-bit Pixel Manipulation
var i = 0;
for (var y = 0; y < canvasHeight; ++y) {
    for (var x = 0; x < canvasWidth; ++x) {
        data32[i++] = 123;
    }
}

imageData.data.set(buf8);
pending…

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