Particular shape image on uiimageview

Question

Can we set below shape on image with UIImageView.

Any idea!

Thanks

Answer 1

Mask UIImageView

You can use mask property of imageView's CALayer:

CALayer *mask = [CALayer layer];
mask.contents = (id)[[UIImage imageNamed:@"mask.png"] CGImage];
mask.frame = CGRectMake(0, 0, imageView.image.size.width, imageView.image.size.height);
imageView.layer.mask = mask;
imageView.layer.masksToBounds = YES;

Apply Core Graphics mask to UIImage

This will apply to ImageView only, so if you want to change UIImage directly - you should use Core Graphics mask:

- (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 maskedImageRef = CGImageCreateWithMask([image CGImage], mask);
    UIImage *maskedImage = [UIImage imageWithCGImage:maskedImageRef];

    CGImageRelease(mask);
    CGImageRelease(maskedImageRef);

    // returns new image with mask applied
    return maskedImage;
}

Core Graphics image composition with blending

Swift 5.

let image = UIImage(named: "Lenna.png")!
let mask = UIImage(named: "mask-image.png")! // background is transparent
let size = image.size

let renderer = UIGraphicsImageRenderer(size: size)
let newImage = renderer.image { context in
    image.draw(in: CGRect(origin: .zero, size: size), blendMode: .normal, alpha: 1)
    mask.draw(in: CGRect(origin: .zero, size: size), blendMode: .destinationIn, alpha: 1)
}

Playground: