gavinsharp

tabs.on('ready', function(tab) {
  reportError("tab activated");
  let gBrowser = Svc.Services.wm.getMostRecentWindow("navigator:browser").gBrowser;
  let doc = gBrowser.contentDocument;
  let browser = gBrowser.getBrowserForDocument(doc);
  if (browser.engines) {
    reportError(Object.keys(browser.engines[0]));
    browser.engines.forEach(function({uri, title, icon}) {
      let type = (/xml$/).test(uri) ? Ci.nsISearchEngine.DATA_XML : Ci.nsISearchEngine.DATA_TEXT;
      let e = Svc.Services.search.currentEngine;

gavinsharp

function getDominantColor(aImg) {
  let canvas = document.createElement("canvas");
  canvas.height = aImg.height;
  canvas.width = aImg.width;

  let context = canvas.getContext("2d");
  context.drawImage(aImg, 0, 0);

  // keep track of how many times a color appears in the image
  let colorCount = {};