Ios zoom and crop image
I am working on an image scaling and cropping feature (similar to camara app) for iOS, the code below works great, just the resulting image came down and I would like to understand why.
thank
- (UIImage*)imageByCropping:(UIImageView *)imageViewToCrop toRect:(CGRect)rect
{
//create a context to do our clipping in
CGRect newRect = CGRectApplyAffineTransform(rect, imageViewToCrop.transform);
UIImage *imageToCrop = imageViewToCrop.image;
UIGraphicsBeginImageContext(newRect.size);
CGContextRef currentContext = UIGraphicsGetCurrentContext();
//create a rect with the size we want to crop the image to
//the X and Y here are zero so we start at the beginning of our
//newly created context
CGRect clippedRect = CGRectMake(0, 0, rect.size.width, rect.size.height);
CGContextClipToRect( currentContext, clippedRect);
//draw the image to our clipped context using our offset rect
CGContextDrawImage(currentContext, newRect, imageToCrop.CGImage);
//pull the image from our cropped context
UIImage *cropped = UIGraphicsGetImageFromCurrentImageContext();
//pop the context to get back to the default
UIGraphicsEndImageContext();
return cropped;
}
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1 answer
I also ran into this problem with no explanation. But found a workaround that solves this problem. Just put the next two lines in your code and try again. This works for me.
CGContextTranslateCTM(context, 0.0, newRect.size.height);
CGContextScaleCTM(context, 1.0, -1.0);//flip context
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