I have a view (testView) that is 400x320 and I need to take a screenshot of part of this view (say rect = (50, 50, 200, 200)). I am playing around with the drawViewHierarchy me
After getting the whole snapshot, you could draw it in a smaller Graphic Context in a way that you get the part you want:
UIGraphicsBeginImageContextWithOptions(CGSizeMake(200, 200), YES, [UIScreen mainScreen].scale);
[image drawInRect:CGRectMake(-50, -50, image.size.width, image.size.height)];
UIImage *finalImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
EDIT: Better yet, draw the hierarchy directly in that smaller context:
UIGraphicsBeginImageContextWithOptions(CGSizeMake(200, 200), NO, [UIScreen mainScreen].scale);
[self.testView drawViewHierarchyInRect:CGRectMake(-50, -50, self.testView.bounds.size.width, self.testView.bounds.size.height) afterScreenUpdates:YES];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();