Resize UIImage Keep Image Quality in Swift - swift

Question

I have created an image from UIView using UIGraphicsGetCurrentContext. It's work fine but when I resized that image to larger size its be blurred with bad quality. Can it possibility to keep quality when resize? I have tried many ways but not work.
- code image:
func image(with view: UIView) -> UIImage? {
UIGraphicsBeginImageContextWithOptions(view.bounds.size, view.isOpaque, 0.0)
defer { UIGraphicsEndImageContext() }
if let context = UIGraphicsGetCurrentContext() {
view.drawHierarchy(in: view.bounds, afterScreenUpdates: true)
context.setAllowsAntialiasing(true)
context.setShouldAntialias(true)
let image = UIGraphicsGetImageFromCurrentImageContext()
return image
}
return nil
}
code I have used to resize, this extension of UIImage
func resizedImage(newSize: CGSize) -> UIImage {
// Guard newSize is different
guard self.size != newSize else { return self }
let aspect_ratio = self.size.width / self.size.height
var image_w = newSize.height * aspect_ratio
let finalSize = CGSize(width: image_w, height: newSize.height)
UIGraphicsBeginImageContextWithOptions(finalSize, false, 0.0)
self.draw(in: CGRect(x: 0, y: 0, width: (CGFloat)(finalSize.width), height: (CGFloat)(newSize.height)))
let newImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
return newImage
}
and the example image:image
Thanks

Answer 1

Try this:
extension UIImage {
func resizeImage(targetSize: CGSize) -> UIImage {
let size = self.size
let widthRatio = targetSize.width / size.width
let heightRatio = targetSize.height / size.height
let newSize = widthRatio > heightRatio ? CGSize(width: size.width * heightRatio, height: size.height * heightRatio) : CGSize(width: size.width * widthRatio, height: size.height * widthRatio)
let rect = CGRect(x: 0, y: 0, width: newSize.width, height: newSize.height)
UIGraphicsBeginImageContextWithOptions(newSize, false, 1.0)
self.draw(in: rect)
let newImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return newImage!
}
}