圆角图片怎么画?

static void addRoundedRectToPath(CGContextRef context, 
                                 CGRect rect, 
                                 float ovalWidth,
                                 float ovalHeight) {
    
    float fw, fh;
    if (ovalWidth == 0 || ovalHeight == 0) {
        CGContextAddRect(context, rect);
        return;
    }
    
    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);  // Start at lower right corner
#pragma mark change the corner size below...
    CGContextAddArcToPoint(context, fw, fh, fw/2, fh, 1);  // Top right corner
    CGContextAddArcToPoint(context, 0, fh, 0, fh/2, 1); // Top left corner
    CGContextAddArcToPoint(context, 0, 0, fw/2, 0, 1); // Lower left corner
    CGContextAddArcToPoint(context, fw, 0, fw, fh/2, 1); // Back to lower right
    
    CGContextClosePath(context);
    CGContextRestoreGState(context);
}


+ (id) createRoundedRectImage:(UIImage*)image size:(CGSize)size {
    // the size of CGContextRef
    int w = size.width;
    int h = size.height;
    
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    CGContextRef context = CGBitmapContextCreate(NULL, w, h, 8, 4 * w, colorSpace, kCGImageAlphaPremultipliedFirst);
    CGRect rect = CGRectMake(0, 0, w, h);
    
    CGContextBeginPath(context);
    addRoundedRectToPath(context, rect, 10, 10);
    CGContextClosePath(context);
    CGContextClip(context);
    CGContextDrawImage(context, CGRectMake(0, 0, w, h), image.CGImage);
    CGImageRef imageMasked = CGBitmapContextCreateImage(context);
    CGContextRelease(context);
    CGColorSpaceRelease(colorSpace);
    return [UIImage imageWithCGImage:imageMasked];
}

 

 

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// Import QuartzCore.h at the top of the file #import <QuartzCore/QuartzCore.h> // Uncomment viewDidLoad and add the following lines self.view.layer.backgroundColor =[UIColor orangeColor].CGColor; self.view.layer.cornerRadius =20.0; self.view.layer.frame = CGRectInset(self.view.layer.frame, 20, 20);