PHP advanced graphics library

I'm developing a graphic manipulation web service in PHP, I want to accept images, apply filters and output them instantly. Is there any library out there to accomplish this task?

(think of filters like the ones used开发者_如何学编程 in this app http://www.toon-fx.com/toonpaint/)

this link contains examples how to create and apply filters. It uses GD library. How To Create and Apply Image Filters in PHP

Supporting Gordon's comment, you should check out PaintbrushJS.

http://mezzoblue.github.com/PaintbrushJS/demo/