Canvas Pixel Manipulation (v3)

Revision 3 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 data16 = new Uint16Array(buf);

Teardown


    ctx.putImageData(imageData, 0, 0);

Test runner

Ready to run.

Testing in
TestOps/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 = x * y & 0xff;

        data[index]   = value;    // red
        data[++index] = value;    // green
        data[++index] = value;    // blue
        data[++index] = 255;      // alpha
    }
}
ready
16-bit Pixel Manipulation
for (var y = 0; y < canvasHeight; ++y) {
    for (var x = 0; x < canvasWidth; ++x) {
        var index = (y * canvasWidth + x) * 2;
        var value = x * y & 0xff;

        data16[index] =
            (255   << 8) |    // alpha
            (value);
        data16[index++] =
            (value <<  8) |    // green
             value;            // red
    }
}

imageData.data.set(data16 );
ready

Revisions

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