UIImageView rounded corners

Works for any UIView, not just images.

1. Add QuartzCore.framework to the list of frameworks.
2. #import <QuartzCore/QuartzCore.h> in the header file.
3. Set the corner radius of view's layer:

// Rounded corners
CALayer *layer = [myView layer];
[layer setMasksToBounds:YES];
[layer setCornerRadius:3.0];

Please note that this method is relatively slow so using it for UITableView icons might feel a little sluggish.

• "Rounded UIView using CALayers - only some corners - How?" on stackoverflow.com

1. Add CoreGraphics.framework to the list of frameworks.
2. Create a category subclass of UIImage class:

UIImageHelloAdditions.h:

@interface UIImage (Hello)
 
// Rounded corners
- (UIImage *)roundCornerImageWithWidth:(NSUInteger)ovalWidth height:(NSUInteger)ovalHeight;
 
@end

UIImageHelloAdditions.m:

#import "UIImageHelloAdditions.h"
 
@implementation UIImage (Hello)
 
 
- (UIImage *)roundCornerImageWithWidth:(NSUInteger)ovalWidth height:(NSUInteger)ovalHeight {
 
	UIImage *newImage = nil;
 
	// Initialize
	NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
	int w = self.size.width;
	int h = self.size.height;
 
	CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
	CGContextRef context = CGBitmapContextCreate(NULL, w, h, 8, 4 * w, colorSpace, kCGImageAlphaPremultipliedFirst);
 
	CGContextBeginPath(context);
	CGRect rect = CGRectMake(0, 0, self.size.width, self.size.height);
 
	// Add rounded rect
	float fw, fh;
	if (ovalWidth == 0 || ovalHeight == 0) {
		CGContextAddRect(context, rect);
		return nil;
	}
	CGContextSaveGState(context);
	CGContextTranslateCTM (context, CGRectGetMinX(rect), CGRectGetMinY(rect));
	CGContextScaleCTM (context, ovalWidth, ovalHeight);
	fw = CGRectGetWidth (rect) / ovalWidth;
	fh = CGRectGetHeight (rect) / ovalHeight;
	CGContextMoveToPoint(context, fw, fh/2);
	CGContextAddArcToPoint(context, fw, fh, fw/2, fh, 1);
	CGContextAddArcToPoint(context, 0, fh, 0, fh/2, 1);
	CGContextAddArcToPoint(context, 0, 0, fw/2, 0, 1);
	CGContextAddArcToPoint(context, fw, 0, fw, fh/2, 1);
	CGContextClosePath(context);
	CGContextRestoreGState(context);
 
	// Clean up
	CGContextClosePath(context);
	CGContextClip(context);
 
	CGContextDrawImage(context, CGRectMake(0, 0, w, h), self.CGImage);
 
	CGImageRef imageMasked = CGBitmapContextCreateImage(context);
	CGContextRelease(context);
	CGColorSpaceRelease(colorSpace);
 
	newImage = [[UIImage imageWithCGImage:imageMasked] retain];
	CGImageRelease(imageMasked);
 
	[pool release];
 
	return newImage;	
}
 
@end

Now, #import "UIImageHelloAdditions.h" wherever you want to get rounded corners and use the

- (UIImage *)roundCornerImageWithWidth:(NSUInteger)ovalWidth height:(NSUInteger)ovalHeight

method to get those.

• "iPhone development – UIImage with round corners" at Björn Sållarp's blog