Image round corner

// UIImage+RoundedCorner.h
// Created by Trevor Harmon on 9/20/09.
// Free for personal or commercial use, with or without modification.
// No warranty is expressed or implied.

// Extends the UIImage class to support making rounded corners
@interface UIImage (RoundedCorner)
- (UIImage *)roundedCornerImage:(NSInteger)cornerSize borderSize:(NSInteger)borderSize;
- (UIImage *) normalize;
@end



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// UIImage+RoundedCorner.m
// Created by Trevor Harmon on 9/20/09.
// Free for personal or commercial use, with or without modification.
// No warranty is expressed or implied.

#import "UIImage+RoundedCorner.h"
#import "UIImage+Alpha.h"

// Private helper methods
@interface UIImage ()
- (void)addRoundedRect2Path:(CGRect)rect context:(CGContextRef)context ovalWidth:(CGFloat)ovalWidth ovalHeight:(CGFloat)ovalHeight;
@end

@implementation UIImage (RoundedCorner)

// Creates a copy of this image with rounded corners
// If borderSize is non-zero, a transparent border of the given size will also be added
// Original author: Björn Sållarp. Used with permission. See: http://blog.sallarp.com/iphone-uiimage-round-corners/
- (UIImage *)roundedCornerImage:(NSInteger)cornerSize borderSize:(NSInteger)borderSize {
    // If the image does not have an alpha layer, add one
    UIImage *image = [self imageWithAlpha];
   
    // Build a context that's the same dimensions as the new size
    CGContextRef context = CGBitmapContextCreate(NULL,
                                                 image.size.width,
                                                 image.size.height,
                                                 CGImageGetBitsPerComponent(image.CGImage),
                                                 0,
                                                 CGImageGetColorSpace(image.CGImage),
                                                 CGImageGetBitmapInfo(image.CGImage));

    // Create a clipping path with rounded corners
    CGContextBeginPath(context);
    [self addRoundedRect2Path:CGRectMake(borderSize, borderSize, image.size.width - borderSize * 2, image.size.height - borderSize * 2)
                       context:context
                     ovalWidth:cornerSize
                    ovalHeight:cornerSize];
    CGContextClosePath(context);
    CGContextClip(context);

    // Draw the image to the context; the clipping path will make anything outside the rounded rect transparent
    CGContextDrawImage(context, CGRectMake(0, 0, image.size.width, image.size.height), image.CGImage);
   
    // Create a CGImage from the context
    CGImageRef clippedImage = CGBitmapContextCreateImage(context);
    CGContextRelease(context);
   
    // Create a UIImage from the CGImage
    UIImage *roundedImage = [UIImage imageWithCGImage:clippedImage];
    CGImageRelease(clippedImage);
   
    return roundedImage;
}

- (UIImage *) normalize {
   
    CGColorSpaceRef genericColorSpace = CGColorSpaceCreateDeviceRGB();
    CGContextRef thumbBitmapCtxt = CGBitmapContextCreate(NULL,
                                                         self.size.width,
                                                         self.size.height,
                                                         8, (4 * self.size.width),
                                                         genericColorSpace,
                                                         kCGImageAlphaPremultipliedFirst);
    CGColorSpaceRelease(genericColorSpace);
    CGContextSetInterpolationQuality(thumbBitmapCtxt, kCGInterpolationDefault);
    CGRect destRect = CGRectMake(0, 0, self.size.width, self.size.height);
    CGContextDrawImage(thumbBitmapCtxt, destRect, self.CGImage);
    CGImageRef tmpThumbImage = CGBitmapContextCreateImage(thumbBitmapCtxt);
    CGContextRelease(thumbBitmapCtxt);   
    UIImage *result = [UIImage imageWithCGImage:tmpThumbImage];
    CGImageRelease(tmpThumbImage);
   
    return result;   
}


#pragma mark -
#pragma mark Private helper methods

// Adds a rectangular path to the given context and rounds its corners by the given extents
// Original author: Björn Sållarp. Used with permission. See: http://blog.sallarp.com/iphone-uiimage-round-corners/
- (void)addRoundedRect2Path:(CGRect)rect context:(CGContextRef)context ovalWidth:(CGFloat)ovalWidth ovalHeight:(CGFloat)ovalHeight {
    if (ovalWidth == 0 || ovalHeight == 0) {
        CGContextAddRect(context, rect);
        return;
    }
    CGContextSaveGState(context);
    CGContextTranslateCTM(context, CGRectGetMinX(rect), CGRectGetMinY(rect));
    CGContextScaleCTM(context, ovalWidth, ovalHeight);
    CGFloat fw = CGRectGetWidth(rect) / ovalWidth;
    CGFloat fh = CGRectGetHeight(rect) / ovalHeight;
    CGContextMoveToPoint(context, fw, fh/2);
    CGContextAddArcToPoint(context, fw, fh, fw/2, fh, 1);
    CGContextAddArcToPoint(context, 0, fh, 0, fh/2, 1);
    CGContextAddArcToPoint(context, 0, 0, fw/2, 0, 1);
    CGContextAddArcToPoint(context, fw, 0, fw, fh/2, 1);
    CGContextClosePath(context);
    CGContextRestoreGState(context);
}

@end
---------------------------------------------
// UIImage+Alpha.h
// Created by Trevor Harmon on 9/20/09.
// Free for personal or commercial use, with or without modification.
// No warranty is expressed or implied.

// Helper methods for adding an alpha layer to an image
@interface UIImage (Alpha)
- (BOOL)hasAlpha;
- (UIImage *)imageWithAlpha;
- (UIImage *)transparentBorderImage:(NSUInteger)borderSize;
@end
 ---------------------------------------------
// UIImage+Alpha.m
// Created by Trevor Harmon on 9/20/09.
// Free for personal or commercial use, with or without modification.
// No warranty is expressed or implied.

#import "UIImage+Alpha.h"

// Private helper methods
@interface UIImage ()
- (CGImageRef)newBorderMask:(NSUInteger)borderSize size:(CGSize)size;
@end

@implementation UIImage (Alpha)

// Returns true if the image has an alpha layer
- (BOOL)hasAlpha {
    CGImageAlphaInfo alpha = CGImageGetAlphaInfo(self.CGImage);
    return (alpha == kCGImageAlphaFirst ||
            alpha == kCGImageAlphaLast ||
            alpha == kCGImageAlphaPremultipliedFirst ||
            alpha == kCGImageAlphaPremultipliedLast);
}

// Returns a copy of the given image, adding an alpha channel if it doesn't already have one
- (UIImage *)imageWithAlpha {
    if ([self hasAlpha]) {
        return self;
    }
   
    CGImageRef imageRef = self.CGImage;
    size_t width = CGImageGetWidth(imageRef);
    size_t height = CGImageGetHeight(imageRef);
   
    // The bitsPerComponent and bitmapInfo values are hard-coded to prevent an "unsupported parameter combination" error
    CGContextRef offscreenContext = CGBitmapContextCreate(NULL,
                                                          width,
                                                          height,
                                                          8,
                                                          0,
                                                          CGImageGetColorSpace(imageRef),
                                                          kCGBitmapByteOrderDefault | kCGImageAlphaPremultipliedFirst);
   
    // Draw the image into the context and retrieve the new image, which will now have an alpha layer
    CGContextDrawImage(offscreenContext, CGRectMake(0, 0, width, height), imageRef);
    CGImageRef imageRefWithAlpha = CGBitmapContextCreateImage(offscreenContext);
    UIImage *imageWithAlpha = [UIImage imageWithCGImage:imageRefWithAlpha];
   
    // Clean up
    CGContextRelease(offscreenContext);
    CGImageRelease(imageRefWithAlpha);
   
    return imageWithAlpha;
}

// Returns a copy of the image with a transparent border of the given size added around its edges.
// If the image has no alpha layer, one will be added to it.
- (UIImage *)transparentBorderImage:(NSUInteger)borderSize {
    // If the image does not have an alpha layer, add one
    UIImage *image = [self imageWithAlpha];
   
    CGRect newRect = CGRectMake(0, 0, image.size.width + borderSize * 2, image.size.height + borderSize * 2);
   
    // Build a context that's the same dimensions as the new size
    CGContextRef bitmap = CGBitmapContextCreate(NULL,
                                                newRect.size.width,
                                                newRect.size.height,
                                                CGImageGetBitsPerComponent(self.CGImage),
                                                0,
                                                CGImageGetColorSpace(self.CGImage),
                                                CGImageGetBitmapInfo(self.CGImage));
   
    // Draw the image in the center of the context, leaving a gap around the edges
    CGRect imageLocation = CGRectMake(borderSize, borderSize, image.size.width, image.size.height);
    CGContextDrawImage(bitmap, imageLocation, self.CGImage);
    CGImageRef borderImageRef = CGBitmapContextCreateImage(bitmap);
   
    // Create a mask to make the border transparent, and combine it with the image
    CGImageRef maskImageRef = [self newBorderMask:borderSize size:newRect.size];
    CGImageRef transparentBorderImageRef = CGImageCreateWithMask(borderImageRef, maskImageRef);
    UIImage *transparentBorderImage = [UIImage imageWithCGImage:transparentBorderImageRef];
   
    // Clean up
    CGContextRelease(bitmap);
    CGImageRelease(borderImageRef);
    CGImageRelease(maskImageRef);
    CGImageRelease(transparentBorderImageRef);
   
    return transparentBorderImage;
}

#pragma mark -
#pragma mark Private helper methods

// Creates a mask that makes the outer edges transparent and everything else opaque
// The size must include the entire mask (opaque part + transparent border)
// The caller is responsible for releasing the returned reference by calling CGImageRelease
- (CGImageRef)newBorderMask:(NSUInteger)borderSize size:(CGSize)size {
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceGray();
   
    // Build a context that's the same dimensions as the new size
    CGContextRef maskContext = CGBitmapContextCreate(NULL,
                                                     size.width,
                                                     size.height,
                                                     8, // 8-bit grayscale
                                                     0,
                                                     colorSpace,
                                                     kCGBitmapByteOrderDefault | kCGImageAlphaNone);
   
    // Start with a mask that's entirely transparent
    CGContextSetFillColorWithColor(maskContext, [UIColor blackColor].CGColor);
    CGContextFillRect(maskContext, CGRectMake(0, 0, size.width, size.height));
   
    // Make the inner part (within the border) opaque
    CGContextSetFillColorWithColor(maskContext, [UIColor whiteColor].CGColor);
    CGContextFillRect(maskContext, CGRectMake(borderSize, borderSize, size.width - borderSize * 2, size.height - borderSize * 2));
   
    // Get an image of the context
    CGImageRef maskImageRef = CGBitmapContextCreateImage(maskContext);
   
    // Clean up
    CGContextRelease(maskContext);
    CGColorSpaceRelease(colorSpace);
   
    return maskImageRef;
}

@end

---------------------------------------------
// import file 
#import "UIImage+RoundedCorner.h"

and call it as 

//calling method
[imageView setImage:[[UIImage imageWithData:data] roundedCornerImage:10 borderSize:1]];