      - seealso:
      [Imgix API Reference](https://www.imgix.com/docs/reference/pixeldensity)
     */
-    public var scale: CGFloat?
+    public var scale: CGFloat? {
+        get { return storage[.scale] as? CGFloat }
+        set { storage[.scale] = newValue }
+    }
 
     /**
      Controls how the output image is fit to its target dimensions.

     [Imgix API Reference](https://www.imgix.com/docs/reference/adjustment#param-exp)
    */
    public var exposure: Int? {
        get { return _exposure }
        set { _exposure = newValue?.clamped(to: -100...100) }
    }
    private var _exposure: Int?

    /**
     Adjusts gamma/midtone brightness.

     - seealso:
     [Imgix API Reference](https://www.imgix.com/docs/reference/size#param-h)
    */
    public var height: CGFloat? {
        get { return storage[.height] as? CGFloat }
        set { storage[.height] = newValue }
    }

    /**
     The device pixel ratio to be used.
