How to tint a transparent PNG image in iPhone?

Question

I know it's possible to tint a rectangular image by drawing a CGContextFillRect over it and setting the blend mode. However, I can't figure out how to do a tint on a transparent image such as an icon. It must be possible since the SDK does it itself on tab-bars in such. Would anyone be able to provide a snippet?

Answer 1

UIImageView (or any view for that matter) has a background color which is RGBA. The alpha in the color may do what you need without inventing something new.

Answer 2

After searching around, the best solution I've come to thus far is to use a combination of blend mode and the clipping mask to achieve colorizing/tinting a transparent PNG:

CGContextSetBlendMode (context, kCGBlendModeMultiply);

CGContextDrawImage(context, rect, myIconImage.CGImage);

CGContextClipToMask(context, rect, myIconImage.CGImage);

CGContextSetFillColorWithColor(context, tintColor);

CGContextFillRect(context, rect);