将方形UIImage裁剪为圆角矩形

Question

I have tried at least 5 different ways that I've found on here, but nothing has worked. All are at least 1-2 years old minimum. Has Apple changed something in the rules since then?

I take a screenshot, crop it to a square, and then I am trying to crop its corners to a radius of 15.

Maybe there is a more serious and certain way to do this with OpenGL?

Trying this solution currently, but the corners still refuse to crop:

-(UIImage*) cropImage:(UIImage*)image withPath:(UIBezierPath*)path { // where the UIBezierPath is defined in the UIKit coordinate system (0,0) is top left

    CGRect r = CGPathGetBoundingBox(path.CGPath); // the rect to draw our image in (minimum rect that the path occupies).

    UIGraphicsBeginImageContextWithOptions(r.size, NO, 0.0); // begin image context, with transparency & the scale of the image.
    CGContextRef ctx = UIGraphicsGetCurrentContext();

    CGContextTranslateCTM(ctx, -r.origin.x, -r.origin.y); // translate context so that when we add the path, it starts at (0,0).

    CGContextAddPath(ctx, path.CGPath); // add path.
    CGContextClip(ctx); // clip any future drawing to the path region.

    [image drawInRect:(CGRect){CGPointZero, image.size}]; // draw image

    UIImage* i = UIGraphicsGetImageFromCurrentImageContext(); // get image from context
    UIGraphicsEndImageContext(); // clean up and finish context

    return i; // return image
}

Just to clarify, I'm trying to actually delete the pixels I crop

And I'm passing in...

[self cropImage:myImage withPath:[UIBezierPath bezierPathWithRoundedRect:CGRectMake(0, 0, screenImage.size.width, screenImage.size.height) cornerRadius:15.0]]

Even if I try greatly increases the corner radius, still nothing happens.

Answer 1

At this point you have probably found some solution out there, but for the next ones that will arrive here this solution here might help. It a bit of a workaround, since it uses a UIImageView to do the drawing job, but it works pretty well.

extension UIImage {

    var circle: UIImage? {
        let length = min(size.width, size.height)
        let imageView = UIImageView(frame: CGRect(origin: .zero, size: CGSize(width: length, height: length)))
        imageView.contentMode = .scaleAspectFill
        imageView.image = self
        imageView.layer.cornerRadius = length/2
        imageView.layer.masksToBounds = true
        UIGraphicsBeginImageContextWithOptions(imageView.bounds.size, false, scale)
        guard let context = UIGraphicsGetCurrentContext() else { return nil }
        imageView.layer.render(in: context)
        let result = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return result
    }
}

If you want a more robust solution, this one here might help: https://github.com/giacgbj/UIImageSwiftExtensions/