CGRect + resize keeping aspect

CGRect.swift

extension CGRect {
    func resized(size: CGSize, aspectFill: Bool) -> CGRect {
        var resizedRect = CGRect.zero;

        let aspectWidth = size.width / self.size.width
        let aspectHeight = size.height / self.size.height
        let aspectRatio = aspectFill ? max(aspectWidth, aspectHeight) : min(aspectWidth, aspectHeight)

        resizedRect.size.width = self.size.width * aspectRatio
        resizedRect.size.height = self.size.height * aspectRatio
        resizedRect.origin.x = (size.width - resizedRect.size.width) / 2
        resizedRect.origin.y = (size.height - resizedRect.size.height) / 2

        return resizedRect
    }
}