Draw selected areas of a UIImage - iphone

Question

I have a UIImage containing an image with a whole bunch of smaller pictures on the image (essentially an image strip containing sprites). I'd like to draw a single sprite onto an area of my UIView.
I can't seem to find a way draw only part of the UIImage onto the view. Is there a method that does this?

Answer 1

I think you may be looking for CGImageCreateWithImageInRect(). You can get a CGImage from a UIImage with the property of the same name.
EDIT: another option that exists in 2014, that did not in 2009, is SpriteKit. Depending on what you might be doing that needs a sprite sheet, that might be useful.

Answer 2

I wrote a UIImage category for handling sprite sheets. Check this out, it may be helpful http://reecon.wordpress.com/2011/11/19/uiimage-sprite-additions-objective-c/
As noted earlier, this category bases on CGImageCreateWithImageInRect() but makes the process of extracting sprites from a single sprite sheet far more convenient and faster.
Link to git hub page:
https://github.com/r3econ/UIImage-Sprite-Additions
You can also install using cocoa pods.

Answer 3

Yep, you sure can with Quartz.
There is a tutorial here that shows you how to take a UIImage and mask a part of it.
http://iosdevelopertips.com/cocoa/how-to-mask-an-image.html
Here is the code from that page (incase it goes down for some reason)
- (UIImage*) maskImage:(UIImage *)image withMask:(UIImage *)maskImage {
CGImageRef maskRef = maskImage.CGImage;
CGImageRef mask = CGImageMaskCreate(CGImageGetWidth(maskRef),
CGImageGetHeight(maskRef),
CGImageGetBitsPerComponent(maskRef),
CGImageGetBitsPerPixel(maskRef),
CGImageGetBytesPerRow(maskRef),
CGImageGetDataProvider(maskRef), NULL, false);
CGImageRef masked = CGImageCreateWithMask([image CGImage], mask);
return [UIImage imageWithCGImage:masked];
}