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Generate (Image) Noise with Canvas

/ Published in: JavaScript
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This allows you to add image noise to the body of your website. simply call generateNoise(), pass an optional opacity parameter, and then apply a background color to the body element in your stylesheet.

It's not ideal, and maybe isn't practical -- but it works. :)

Adapted from: http://mitchj.info/blog/2010/09/generate-background-noise-with-jquery/

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Copy this code and paste it in your HTML 
  1. function generateNoise(opacity) {
  2.    if ( !!!document.createElement('canvas').getContext ) {
  3.       return false;
  4.    }
  5.  
  6.    var canvas = document.createElement("canvas"),
  7.    ctx = canvas.getContext('2d'),
  8.    x, y,
  9.    number,
  10.    opacity = opacity || .2;
  11.  
  12.    canvas.width = 45;
  13.    canvas.height = 45;
  14.  
  15.    for ( x = 0; x < canvas.width; x++ ) {
  16.       for ( y = 0; y < canvas.height; y++ ) {
  17.          number = Math.floor( Math.random() * 60 );
  18.  
  19.          ctx.fillStyle = "rgba(" + number + "," + number + "," + number + "," + opacity + ")";
  20.          ctx.fillRect(x, y, 1, 1);
  21.       }
  22.    }
  23.  
  24.    document.body.style.backgroundImage = "url(" + canvas.toDataURL("image/png") + ")";
  25. }
  26. generateNoise(.1); // default opacity is .2

URL: http://nettuts.s3.amazonaws.com/854_noiseWithCanvas/noise.html

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