nowrep/QupZilla — pull request #378 by ariya (2012-04-12 04:33:07+00:00)
Title: More memory efficient and faster preview generation.

There is no need to allocate a very large image buffer, just enough for
the thumbnail preview. For a little filtering, use the two-stage
scaling. See http://labs.qt.nokia.com/2009/01/26/creating-thumbnail-preview/
for the details.

This tecnique is adopted from my live preview implementation for Arora:
http://ariya.ofilabs.com/2008/07/be-my-mirror-my-sword-and-shield.html.