How to draw a shape on top of a UIImage while respecting the image's alpha mask

Question

I need a UIImageView that can draw itself in color or b/w according to a flag:

  BOOL isGrey;

I\'m trying to do it by drawing a black rectangle

Answer 1

I'd take the easy way out and draw a black circle with the same size as the round image you have. Probably not what you are asking for.