UIImage with transparent rounded corners

Question

I\'m using following code to add rounded corners to my UIImage, but the problem is that the rounded corners are showing \"white\" area instead of transparent or \"clear\". W

Answer 1

https://github.com/detroit-labs/AmazeKit

sounds like a job for a library

Answer 2

Here's a simpler formulation using UIKit calls:

- (UIImage*) roundCorneredImage: (UIImage*) orig radius:(CGFloat) r {
    UIGraphicsBeginImageContextWithOptions(orig.size, NO, 0);
    [[UIBezierPath bezierPathWithRoundedRect:(CGRect){CGPointZero, orig.size} 
                                cornerRadius:r] addClip];
    [orig drawInRect:(CGRect){CGPointZero, orig.size}];
    UIImage* result = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return result;
}

Notice the NO parameter - this makes the image context transparent, so the clipped-out region is transparent.

Answer 3

profileImageView.layer.cornerRadius = profileImageView.frame.size.height/2;
profileImageView.clipsToBounds = YES;

Answer 4

Right after creating the bitmap context clear it with:

CGContextClearRect (context, CGRectMake(0, 0, w, h));

Answer 5

lukya's comment below your question is what you probably want to do.

Make sure you import QuartzCore:

#import <QuartzCore/QuartzCore.h>

Then, if you have a UIImageView of your image that you want to have rounded corners, just call (assuming imageView is a property and cornerRadius is the desired corner radius):

self.imageView.layer.cornerRadius = cornerRadius;
self.imageView.clipsToBounds = YES;

Since you already have self.CGImage, you could do this to create a UIImageView:

UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageWithCGImage:self.CGImage]];

Just make sure to release the imageView after you add it as a subview.