firefox addon sdk 1.17 take screenshot

Question

I'm developing a Firefox add-on using sdk 1.17. It contains a panel with a button inside (Developed using ExtJs), I want to take the screen shot of the current page when user clicks the button. In Google chrome there is an API (chrome.page-capture) is there. But I could not find the similar one in Firefox. In firefox how to do this task from the main.js.

Answer 1

O.k I have found the answer. This code can be used to take the full page screen shot.

In your main.js add this code.

  var window = require('sdk/window/utils').getMostRecentBrowserWindow();
  var tab = require('sdk/tabs/utils').getActiveTab(window);
  var myData;
  tabs.activeTab.attach({
    contentScript: "self.postMessage(document.body.scrollHeight);",//recieves the total scroll height of tab
    onMessage: function(data)
    {
      console.log("Tab data received: " + data);
      myData = data;
      var thumbnail = window.document.createElementNS("http://www.w3.org/1999/xhtml", "canvas");
      window = tab.linkedBrowser.contentWindow;
      thumbnail.width = window.screen.availWidth ;
      thumbnail.height = window.screen.availHeight ;
      var ctx = thumbnail.getContext("2d");
      var snippetWidth = window.outerWidth ;
      var snippetHeight = window.outerHeight ;
      ctx.canvas.left  = 0;
      ctx.canvas.top = 0;
      ctx.canvas.width  = window.innerWidth;
      ctx.canvas.height = myData;//canvas height is made equal to the scroll height of window
      ctx.drawWindow(window, 0, 0, snippetWidth, snippetHeight+myData, "rgb(255,255,255)");//

      var imageDataUri=thumbnail.toDataURL('image/png');
      imageDataUri = imageDataUri.replace("image/png", "image/octet-stream");        
      tabs.open(imageDataUri);
    }
  });

This is done with addon sdk 1.17. Works cool.