Draw portion of image in CGBitmapContext

Question

I have created a CGBitmapContext of 256 x 256 and I have a CGImageRef that I want to draw into this context. My goal is to crop the image (and ultimately create tiles of an image), but if I use CGContextDrawImage, Core Graphics scales the image to fit the context.

So the question is, how do I make sure that only a portion of the CGImageRef is drawn into the CGBitmapContext (no scaling)?

Answer 1

CGContextDrawImage takes a CGRect parameter. It sounds like you are passing the bounds of your context. Instead, try passing the bounds of the image, offset appropriately to draw the desired part of it.