How to crop an image in swift

Question

I want to crop an image from camera. There should be a rectangle border in the camera preview and the result will be the cropped image, like this example:

Answer 1

extension UIImage {  
    // Crops an input image (self) to a specified rect
    func cropToRect(rect: CGRect!) -> UIImage? {
        // Correct rect size based on the device screen scale
        let scaledRect = CGRectMake(rect.origin.x * self.scale, rect.origin.y * self.scale, rect.size.width * self.scale, rect.size.height * self.scale);
        // New CGImage reference based on the input image (self) and the specified rect
        let imageRef = CGImageCreateWithImageInRect(self.CGImage, scaledRect);
        // Gets an UIImage from the CGImage
        let result = UIImage(CGImage: imageRef, scale: self.scale, orientation: self.imageOrientation)
        // Returns the final image, or NULL on error
        return result;
    }    
}

// Crops an image to 100x100 pixels, 150px from left and 200px from top
let exampleImage = UIImage(named: "yourImageFile")
let croppedImage = exampleImage?.cropToRect(CGRectMake(150.0, 200.0, 100.0, 100.0))
if croppedImage != nil {
    // Your image was cropped
} else {
    // Something went wrong
}