Canvas Pixel Manipulation (v53)

Revision 53 of this benchmark created by Russell Chapman on

Description

Tests manipulating pixels in canvas with and without y*canvasWidth stored in a lookup table

Preparation HTML

<canvas id="canvas" height="600" width="600">
</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);
    
    var indexLookup = [];
    for (var y = 0; y < canvasHeight; y++) {
      indexLookup[y] = y * canvasWidth;
    }

Teardown


    ctx.putImageData(imageData, 0, 0);

Test runner

Ready to run.

Testing in
TestOps/sec
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);
ready
32-bit Pixel Manipulation w/index lookup
for (var y = 0; y < canvasHeight; ++y) {
  for (var x = 0; x < canvasWidth; ++x) {
    var value = x * y & 0xff,
        index = indexLookup[y] + x;

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

imageData.data.set(buf8);
ready

Revisions

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