rogerwang/node-webkit — pull request #436 by zhchbin (2013-02-10 06:17:47+00:00)
Title: [API] Support api in the window to capture the visible page. 

Fix #81.

simple usage:
index.html, In the `popup.html` there is an image element whose id is `image`.
```javascript
var gui = require('nw.gui');
var win = gui.Window.get();
function takeSnapshot() {
win.capturePage(function(img) {
var popWindow = gui.Window.open('popup.html');
popWindow.on('loaded', function() {
var image = popWindow.window.document.getElementById('image');
image.src = img;
});
}, 'png');
}
```

A big patch maybe, had tested in windows and linux.