iOS : Cropping Image from Rotated ImageView - ios

Question

How to crop a rectangle(red square in screen shot) of UIImage which is rotated as well as zoomed using UIScrollView.
The edges of UIImageView are hidden because of rotation(UIImageView Transformation). Please help.

Answer 1

Well, you can do all the complicated core graphics things or do a simple UIView screenshot. I vote for the easy solution: What you have to do is create a new view with the frame same as where that small rect lies. Then add the whole image view to that small view converting its frame so it looks the same. Then take the screenshot of the small view. After you are done simply put the image view back the way it was and remove the small view.
As this is still easier said then done here is some code to chew on (I did NOT test this so please correct the bugs if any after you succeed).
- (UIImage *)getScreenshotInRect:(CGRect)frame {
UIImageView *theImageView; //your original image view
UIView *backupSuperView = theImageView.superview; //backup original superview
CGRect backupFrame = theImageView.frame; //backup original frame
UIView *frameView = [[UIView alloc] initWithFrame:frame]; //create new view where the image should be taken at
frameView.clipsToBounds = YES; //not really necessery but can be usefull for cases like using corner radius
[self addSubview:frameView];
theImageView.frame = [theImageView.superview convertRect:theImageView.frame toView:frameView]; //set the new frame for the image view
[frameView addSubview:theImageView];
UIImage *toReturn = [self imageFromView:frameView]; //get the screenshot
theImageView.frame = backupFrame; //reset the image view frame
[backupSuperView addSubview:theImageView]; //reset the image view's superview
[frameView removeFromSuperview];
frameView = nil;
return toReturn;
}
- (UIImage *)imageFromView:(UIView *)view {
UIGraphicsBeginImageContextWithOptions(view.bounds.size, view.opaque, .0f);
[view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage * img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return img;
}
I do hope this doesn't break because you have rotations. If that is the case I suggest you create another view on which the rotated image view lies and add this view to the small view.