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Delete white background of images

Replace white pixels of all images with transparent. Requires Canvas support.

  1. // ==UserScript==
  2. // @name        Delete white background of images
  3. // @description Replace white pixels of all images with transparent. Requires Canvas support.
  4. // @include http://devdb.ru/*
  5. // @grant none
  6. // @version 0.0.1.20140630035011
  7. // @namespace https://greatest.deepsurf.us/scripts/68
  8. // ==/UserScript==
  9.   
  10. // History
  11. // 2013-10-23 : Created first version 
  12.  
  13. var imgs = document.getElementsByTagName('img');
  14.  
  15. for (var i = 0;i<imgs.length;) {
  16.     var node = imgs[i], newNode = document.createElement("canvas");
  17.     node.parentNode.replaceChild(newNode, node);
  18.     newNode.id = node.id;
  19.     newNode.class = node.class;
  20.     var width = node.width || node.clientWidth;
  21.     var height = node.height || node.clientHeight;
  22.     newNode.setAttribute('width', width);
  23.     newNode.setAttribute('height', height);
  24.  
  25.     var canvas = newNode.getContext("2d");
  26.     canvas.drawImage(node, 0, 0);
  27.     imageData = canvas.getImageData(0,0,width,height);
  28.     index = 0;
  29.     for (y = 0; y < height; y++) {
  30.         for (x = 0; x < width; x++) {
  31.             if (imageData.data[index] > 247 &&
  32.                 imageData.data[index+1] > 247 &&
  33.                 imageData.data[index+2] > 247)
  34.                     imageData.data[index+3] = 0;
  35.             index += 4;
  36.         }
  37.     }
  38.  
  39.     canvas.putImageData(imageData, 0, 0); 
  40. }