I'm porting old app and replacing old QuickDraw drawing with Quartz one. There are a lot of "hilites" in old code that typically replaces background color with selection color inside cell/rectangle. How to make same with Quartz?
What I tried is:
1) Use cache CGBitmapContextRef. It works but now app took ~300Mb of RAM (vs 50 before). From what I read I've figured out - it's conceptual mistake, triple-buffer.
2) Ok, so I've switched to Quatz "blend modes". There are a lot of them, but no one does what I need. If I change background, so text's and other colors are changed too.
I can't find a way to replace a color selectively.