[Tips] Show Circle in iOS app

show circle in iOS, in my old app https://itunes.apple.com/cn/app/jie-zhong-ri-ji/id513220773?mt=8

first get baby icon,and add a circle crop,after that ,Superposition it with background image 

Iike this:

code 

double radians (double degrees) {return degrees * M_PI/180;}





-(UIImage*)createIconWithImage:(UIImage*)src

{

    UIImage *circle=[UIImage imageNamed:@"Face@2x.png"];

    CGFloat width=circle.size.width;

    CGFloat height=circle.size.height;

   

    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();

    CGContextRef context = CGBitmapContextCreate(NULL, width, height, 8, 4 * width, colorSpace, kCGImageAlphaPremultipliedFirst);

    

    CGContextDrawImage(context, CGRectMake(0, 0, width, height), circle.CGImage);

    

    if (src.imageOrientation == UIImageOrientationLeft) {

        CGContextRotateCTM (context, radians(90));

        CGContextTranslateCTM (context, 0, -height);

        

    } else if (src.imageOrientation == UIImageOrientationRight||src.imageOrientation == UIImageOrientationRightMirrored) {

        CGContextRotateCTM (context, radians(-90));

        CGContextTranslateCTM (context, -width, 0);

        

    } else if (src.imageOrientation == UIImageOrientationUp) {

        // NOTHING

    } else if (src.imageOrientation == UIImageOrientationDown) {

        CGContextTranslateCTM (context, width, height);

        CGContextRotateCTM (context, radians(-180.));

    }

    CGContextBeginPath(context);

    

    CGContextTranslateCTM (context, 4, 4);

    CGRect rect = CGRectMake(0, 0, width-12, height-12);

    CGContextAddEllipseInRect(context, rect);

    CGContextClosePath(context);

    CGContextClip(context);

    CGContextDrawImage(context, rect , src.CGImage);

    

    CGImageRef imageMasked = CGBitmapContextCreateImage(context);

    CGContextRelease(context);

    CGColorSpaceRelease(colorSpace);

 UIImage *image = [UIImage imageWithCGImage:imageMasked];

 CGImageRelease(imageMasked);

    return image;

}

I thank there has a good way do this work, I use code do this like first picture in this article.

sample code : 

#import <QuartzCore/QuartzCore.h>        

        self.contentView.layer.cornerRadius = 35.0;

        self.contentView.layer.borderWidth = 1.0f;



        self.contentView.layer.borderColor = [UIColor blueColor].CGColor;

        self.contentView.layer.shadowColor = [UIColor blueColor].CGColor;

        self.contentView.layer.shadowOffset = CGSizeMake(2.0, 2.0);

        self.contentView.layer.shadowOpacity= 0.5;

        self.contentView.backgroundColor = [UIColor underPageBackgroundColor];

reference 

Apple CALayer Class Reference