Canvas Pixel Manipulation (v98)

Revision 98 of this benchmark created on

Description

Tests two different methods of manipulating pixels using the canvas.

Preparation HTML

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

Setup

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 buf8 = new Uint8ClampedArray(buf);
    var data32 = new Uint32Array(buf);

Teardown


    ctx.putImageData(imageData, 0, 0);

Test runner

Ready to run.

Testing in
TestOps/sec
8-bit Pixel Manipulation
var index = 0;
for (var y = 0; y < canvasHeight; ++y) {
  for (var x = 0; x < canvasWidth; ++x) {

    var value = x * y & 0xff;

    data[++index] = value; // red
    data[++index] = value; // green
    data[++index] = value; // blue
    data[++index] = 255; // alpha
  }
}
ready
32-bit Pixel Manipulation
var y = 0;
while (y < canvasHeight) {
  var x = 0;
  var w = y * canvasWidth;
  while (x < canvasWidth) {
    var value = x * y & 0xff;

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

imageData.data.set(buf8);
ready

Revisions

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