IOS 图片处理成圆形

#import <UIKit/UIKit.h>

@interface UIImage (Rounded)

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

@end

#import "UIImage+Rounded.h"

@implementation UIImage (Rounded)

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 radius:(NSInteger)r
{
// 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, r, r);
CGContextClosePath(context);
CGContextClip(context);
CGContextDrawImage(context, CGRectMake(0, 0, w, h), img.CGImage);
CGImageRef imageMasked = CGBitmapContextCreateImage(context);
img = [UIImage imageWithCGImage:imageMasked];

CGContextRelease(context);
CGColorSpaceRelease(colorSpace);
CGImageRelease(imageMasked);

return img;
}