Horizontal flip in CGontextRef.

If you want to do the mirror image of the CGContext, then you want to do the horizontal flip. Use following 2 lines of code:

CGAffineTransform transform = CGAffineTransformMake(-1.0, 0.0, 0.0, 1.0, widthOfScreen, 0.0);

CGContextConcatCTM(context,transform);

For vertical flip, follow this article: LINK