How set the scale of a TControl?

Question

In XE2, I simply used the Scale property to set a control's x- and y-axis scales. In subsequent versions, apparently, the Scale property has become protected in TControl and is published in descended controls.

I have quite a few functions that take a TControl reference and manipulate its scale.

What is the preferred method to set a TControl's scale in 10.2?

Answer 1

You can use the protected hack to overcome this:

TYPE
  TControlHack = CLASS(TControl);

PROCEDURE SetScale(C : TControl ; NewScale : TPosition);
  BEGIN
    TControlHack(C).Scale:=NewScale
  END;

By declaring a new class inheriting from the original class, you are in effect "dragging" the protected definitions into view when you hard cast the instance to this new class.

You could also implement it as a class helper:

TYPE
  TControlHelper = CLASS HELPER FOR TControl
                   STRICT PRIVATE
                     PROCEDURE SetScale(Value : TPosition); INLINE;
                     FUNCTION GetScale : TPosition; INLINE;
                   PUBLIC
                     PROPERTY Scale : TPosition Read GetScale Write SetScale;
                   END;

FUNCTION TControlHelper.GetScale : TPosition;
  BEGIN
    Result:=INHERITED Scale
  END;

PROCEDURE TControlHelper.SetScale(Value : TPosition);
  BEGIN
    INHERITED Scale:=Value
  END;