I’m trying to implement a painting app with brush texture and blending, similar to that of an oil painting. I’m finding that even though Quartz 2D has been relatively simple to pick up, I’ve found it hard to implement the ideas of stroke texture/blending. Naively I tried hacking the shadow, and it looks “okay,” but the performance sucks. I have a feeling that if I try to use a bitmap image for drawing I will have similar performance issues, but I do not know that to be the case. Meanwhile, the only alternative I see around is OpenGL, which feels like overkill and also is pretty intimidating. I’ve looked at GLPaint and I can’t claim to understand some parts of it. Further working against me is that my knowledge of C is extremely limited and it really feels like if I understood C better I might understand OpenGL ES for iOS better as well.
Basically, I am wondering: given my requirement of producing an “oil painting” type effect for iOS painting, am I relegated to either the poor performance of Quartz 2D or learning the gigantic and honestly scary OpenGL framework? Are there any frameworks that “wrap” OpenGL functionality for mere mortals like myself?
Or, is there some other way of achieving stroke texture and blending that I am not aware of in Quartz?
iOS 5’s GLKit will wrap a lot of OpenGL functionality for you, but it’s going to be difficult to find an “oil painting library” because it is quite specific. If you want to work with graphics, sooner or later you are going to have to deal with OpenGL I imagine. It seems intimidating, but if you read a good book on it you will start to understand it better.
However, make sure you exhaust your possibilties on Quartz first. Perhaps you can find the function that is taking the most time and ask another question about how to improve its efficiency.
To answer the main question though, “yes”.