Drawing a circular image on top of another image - UIGraphicsBeginImageContextWithOptions

Question

I've been struggling with this method for a while. I am drawing an avatar on top of another image. The user picture I want to be a circle, however I can't seem to figure out how. The user picture is a UIImage and not a UIImageView. I am aware of how to make a circle if it is an imageview. Below is the code. There might be a better approach.

-(UIImage *)drawImage:(UIImage*)pinImage withBadge:(UIImage *)user{



    UIGraphicsBeginImageContextWithOptions(pinImage.size, NO, 0.0f);
    [pinImage drawInRect:CGRectMake(0, 0, pinImage.size.width, pinImage.size.height)];
    [user drawInRect:CGRectMake(20.0, 10.0, user.size.width/2, user.size.height/2)];
    UIImage *resultImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return resultImage;

}

The result is good, but the user image is still square, it is not circle. I have tried making the add the User image to a UIImageView, transform it to a circle, and then use it in the method by calling yourImageView.image, but no luck. I also tried numerous other ways. My logic is more than likely incorrect.

The desired outcome is a rounded image place on top of a pin/annotation. Where the black dot would be an image (a bigger circle than this).

Answer 1

You can clip the image context to the path of an image

// Start the image context
UIGraphicsBeginImageContextWithOptions(pinImage.size, NO, 0.0);
UIImage *resultImage = nil;

// Get the graphics context
CGContextRef context = UIGraphicsGetCurrentContext();

// Draw the first image
[pinImage drawInRect:CGRectMake(0, 0, pinImage.size.width, pinImage.size.height)];

// Get the frame of the second image
CGRect rect = CGRectMake(20.0, 10.0, user.size.width/2, user.size.height/2)

// Add the path of an ellipse to the context
// If the rect is a square the shape will be a circle
CGContextAddEllipseInRect(context, rect);
// Clip the context to that path
CGContextClip(context);

// Do the second image which will be clipped to that circle
[user drawInRect:rect];

// Get the result
UIImage *resultImage = UIGraphicsGetImageFromCurrentImageContext(); 

// End the image context
UIGraphicsEndImageContext();