how adding alpha in a region of the uiimageview - ios

Question

is it possible to add an alpha property on a region in the same image?
For example

Answer 1

The easiest solution would be to break the image apart and save the alpha as part of a png, then organize the imageviews to be flush against each other.
Otherwise, I wrote this quick code in a regular view that does the same with an image (I'm relatively new to Core Graphics so I'm sure there are better ways of doing this - also, my example the images are side by side):
-(void) drawRect {
// GET THE CONTEXT, THEN FLIP THE COORDS (my view is 189 ponts tall)
CGContextRef context = UIGraphicsGetCurrentContext();
CGAffineTransform flip = CGAffineTransformMake(1, 0, 0, -1, 0, 189);
CGContextConcatCTM(context, flip);
// GET THE IMAGE REF
UIImage *targetImage = [UIImage imageNamed:#"test.jpg"];
CGImageRef imageRef = targetImage.CGImage;
// SET THE COORDS
CGRect imageCoords = CGRectMake(0, 0, 116, 189);
CGRect imageCoordsTwo = CGRectMake(116, 0, 117, 189);
// CUT UP THE IMAGE INTO TWO IMAGES
CGImageRef firstImage = CGImageCreateWithImageInRect(imageRef, imageCoords);
CGImageRef secondImage = CGImageCreateWithImageInRect(imageRef, imageCoordsTwo);
// DRAW FIRST IMAGE, SAVE THE STATE, THEN SET THE TRANSPARENCY AMOUNT
CGContextDrawImage(context, imageCoords, firstImage);
CGContextSaveGState(context);
CGContextSetAlpha(context, .4f);
// DRAW SECOND IMAGE, RESTORE THE STATE
CGContextDrawImage(context, imageCoordsTwo, secondImage);
CGContextRestoreGState(context);
// TIDY UP
CGImageRelease(firstImage);
CGImageRelease(secondImage);
}