iPhone custom camera overlay (plus image processing) : how-to [duplicate]

Answer 1

For image processing (regarding our discuss in the comments), you could take a look at this :

http://code.google.com/p/simple-iphone-image-processing/

http://sourceforge.net/projects/photoshopframew/

https://github.com/esilverberg/ios-image-filters

http://developer.apple.com/library/ios/#samplecode/QuartzDemo/Introduction/Intro.html

http://cocoawithlove.com/2011/01/advanced-drawing-using-appkit.html