Draw circle and store in UIImage

How do I draw a filled circle with core graphics and return it as a UIImage?

I want to do something like the following:

+ (UIImage*) circleImageWithRadius:(CGFloat)radius fillColor:开发者_开发知识库(UIColor*)clr;

This should get you most of the way there: http://www.codza.com/creating-and-drawing-on-a-new-uiimage

Also look at CGContextFillEllipseInRect: http://developer.apple.com/library/mac/#documentation/GraphicsImaging/Reference/CGContext/Reference/reference.html