ariya/phantomjs — pull request #11803 by DrMiaow (2013-12-03 04:13:18+00:00)
Title: Added onRepaint callback to webpage API.

Enables subscription to RepaintRequested events.
When the callback is invoked the time that the repaint was requested as well as the x,y and width,height of the repainted rectangle are provided as parameters.
Usage: page.onRepaint = function(time, x, y, width, height) { }

https://github.com/ariya/phantomjs/issues/11793