Canvas Pixel Manipulation

JavaScript performance comparison

Revision 144 of this test case created by Carter

Preparation code

<canvas id="canvas" height="256" width="256"></canvas>
      
<script>
Benchmark.prototype.setup = function() {
  var canvas = document.getElementById('canvas');
  var canvasWidth = canvas.width;
  var canvasHeight = canvas.height;
  var ctx = canvas.getContext('2d');
  var imageData = ctx.getImageData(0, 0, canvasWidth, canvasHeight);
  
  var data = imageData.data;
  
  
  var buf = new ArrayBuffer(imageData.data.length);
  var d32=new Uint32Array(imageData.data.buffer);
  var buf8 = new Uint8ClampedArray(buf);
  var data32 = new Uint32Array(buf);
  var _x = 0;
  var _y = 0;
  var _v = 0;
  var _yd = 0;
  var totalDims = canvasWidth * canvasHeight;

};

Benchmark.prototype.teardown = function() {
  ctx.putImageData(imageData, 0, 0);

};
</script>

Preparation code output

<canvas id="canvas" height="256" 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
Test3
for (var i = 0; i < 65536; i++) {
  _x = i % 256;
  _y = ~~ (i / 256);
  _v = _x * _y & 0xff;
  data32[i] =
    (255 << 24) | // alpha
  (_v << 16) | // blue
  (_v << 8) | // green
  _v; // red

}

imageData.data.set(buf8);
pending…
Test4
for (_y = 0; _y < canvasHeight; _y++) {
  _yd = canvasWidth * _y;
  for (_x = 0; _x < canvasWidth; _x++) {
    _v = _x * _y & 0xff;

    data32[_yd + _x] =
      (255 << 24) | // alpha
    (_v << 16) | // blue
    (_v << 8) | // green
    _v; // red
  }
}

imageData.data.set(buf8);
pending…
8-bit Pixel Manipulation
for (var y = 0; y < canvasHeight; ++y) {
  for (var x = 0; x < canvasWidth; ++x) {
    var value = x * y & 0xff;

    d32[y * canvasWidth + x] =
      (255 << 24) | // alpha
    (value << 16) | // blue
    (value << 8) | // green
    value; // red
  }
}
pending…
32-bit Pixel Manipulation
for (var y = 0; y < canvasHeight; ++y) {
  for (var x = 0; x < canvasWidth; ++x) {
    var value = x * y & 0xff;

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

imageData.data.set(buf8);
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