question: public void transform ( AffineTransform Tx ) { mGraphics . transform ( Tx ) ; }
target:  Composes a Transform object with the transform in this Graphics2D according to the rule last-specified-first-applied. If the currrent transform is Cx, the result of composition with Tx is a new transform Cx'.  Cx' becomes the current transform for this Graphics2D. Transforming a point p by the updated transform Cx' is equivalent to first transforming p by Tx and then transforming the result by the original transform Cx.  In other words, Cx'(p) = Cx(Tx(p)). A copy of the Tx is made, if necessary, so further modifications to Tx do not affect rendering.