设置UIImage 圆角

 //设置UIImage圆角

@interface UIImage(UIRoundedRectImage)

+ (id) createRoundedRectImage:(UIImage*)image size:(CGSize)size;

@end

@implementation UIImage(UIRoundedRectImage)

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

    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;

    

    UIImage *img = image;

    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, 5, 5);

    CGContextClosePath(context);

    CGContextClip(context);

    CGContextDrawImage(context, CGRectMake(0, 0, w, h), img.CGImage);

    CGImageRef imageMasked = CGBitmapContextCreateImage(context);

    CGContextRelease(context);

    CGColorSpaceRelease(colorSpace);

    return [UIImage imageWithCGImage:imageMasked];

}

@end