UIImage aspect fill - ios

Question

I'm trying to perform aspect fill on UIImage (with reusable extension), but I've only got this far:
extension UIImage {
func resizeToCircleImage(targetSize: CGSize, contentMode: UIViewContentMode) -> UIImage {
UIGraphicsBeginImageContextWithOptions(targetSize, true, 0.0)
let rect = CGRect(x: 0, y: 0, width: targetSize.width, height: targetSize.height)
self.draw(in: rect)
let newImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return newImage!
}
}
So, this is for an MKAnnotationView.
It end up looking like this:
But I wanted to aspect fit this image:
https://en.wikipedia.org/wiki/Panorama#/media/File:Panorama_of_the_courtyard_of_the_Great_Mosque_of_Kairouan.jpg

Answer 1

Considering a category of UIImage,
- (UIImage *)aspectFillToSize:(CGSize)size
{
CGFloat imgAspect = self.size.width / self.size.height;
CGFloat sizeAspect = size.width/size.height;
CGSize scaledSize;
if (sizeAspect > imgAspect) { // increase width, crop height
scaledSize = CGSizeMake(size.width, size.width / imgAspect);
} else { // increase height, crop width
scaledSize = CGSizeMake(size.height * imgAspect, size.height);
}
UIGraphicsBeginImageContextWithOptions(size, NO, 0.0f);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextClipToRect(context, CGRectMake(0, 0, size.width, size.height));
[self drawInRect:CGRectMake(0.0f, 0.0f, scaledSize.width, scaledSize.height)];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}

Answer 2

Swift extension version of code from "karim":
private extension UIImage {
func resize(to newSize: CGSize) -> UIImage? {
guard size != newSize else {
return self
}
let imgAspect = size.width/size.height
let sizeAspect = newSize.width/newSize.height
let scaledSize: CGSize
if sizeAspect > imgAspect {
scaledSize = CGSize(width: newSize.width, height: newSize.width/imgAspect)
} else {
scaledSize = CGSize(width: newSize.height * imgAspect, height: newSize.height)
}
UIGraphicsBeginImageContextWithOptions(newSize, true, 1.0)
defer { UIGraphicsEndImageContext() }
let context = UIGraphicsGetCurrentContext()
guard let context = context else {
return nil
}
context.clip(to: CGRect(origin: .zero, size: newSize))
draw(in: CGRect(origin: .zero, size: scaledSize))
return UIGraphicsGetImageFromCurrentImageContext()
}
}