Cropping an image - ios

Question

I use two different methods to crop the center square out of this image. One works, one doesn't. My question is why.
Here are the two results:
Clearly, the left is buggy and the right works.
The image you see on the left uses only CGImageCreateWithImageInRect to
select the region of the image, where the rect is scaled by the ratio of the
original image dimensions to those of the view's dimensions. Why doesn't this method work?
The image you see on the right translates the image and then selects the region
of interest with the origin at 0,0 using CGImageCreateWithImageInRect
Here's the code that draws both images:
- (UIImage *)cropImage:(UIImage *)original inRect:(CGRect)rect {
CGFloat heightScale = original.size.height / self.view.frame.size.height;
CGFloat widthScale = original.size.width / self.view.frame.size.width;
CGRect scaledRect = CGRectMake(rect.origin.x * widthScale, rect.origin.y * heightScale, rect.size.width * widthScale, rect.size.height * heightScale);
UIGraphicsBeginImageContextWithOptions(original.size, YES, 1.0);
[original drawAtPoint:CGPointMake(-scaledRect.origin.x, -scaledRect.origin.y)];
UIImage *translatedImage = UIGraphicsGetImageFromCurrentImageContext();
CGRect finalRect = CGRectMake(0, 0, scaledRect.size.width, scaledRect.size.height);
CGImageRef imageRefForRightImage = CGImageCreateWithImageInRect([translatedImage CGImage], finalRect);
CGImageRef imageRefForLeftImage = CGImageCreateWithImageInRect([original CGImage], scaledRect);
UIImage *croppedRightImage = [UIImage imageWithCGImage:imageRefForRightImage];
UIImage *croppedLeftImage = [UIImage imageWithCGImage:imageRefForLeftImage];
CGImageRelease(imageRefForRightImage);
CGImageRelease(imageRefForLeftImage);
UIImageView *colorImageView = [[UIImageView alloc] initWithFrame:self.view.frame];
colorImageView.backgroundColor = [UIColor purpleColor];
[self.view addSubview:colorImageView];
CGRect rectLeft = CGRectMake(0, 0, 160, 160);
CGRect rectRight = CGRectMake(160, 0, 160, 160);
UIImageView *croppedImageViewLeft = [[UIImageView alloc] initWithFrame:rectLeft];
UIImageView *croppedImageViewRight = [[UIImageView alloc] initWithFrame:rectRight];
croppedImageViewLeft.image = croppedLeftImage;
croppedImageViewRight.image = croppedRightImage;
croppedImageViewLeft.contentMode = UIViewContentModeScaleAspectFit;
croppedImageViewRight.contentMode = UIViewContentModeScaleAspectFit;
[self.view addSubview:croppedImageViewLeft];
[self.view addSubview:croppedImageViewRight];
croppedImageViewRight.image = croppedRightImage;
croppedImageViewLeft.image = croppedLeftImage;
return croppedRightImage;
}