coordinates which makes it possible to reuse the same code to draw a figure and
its mirror -- i.e. reflection related to the diagonal line $x == y$.
-wxMirrorDC has been added in wxWindows version 2.5.0.
+wxMirrorDC has been added in wxWidgets version 2.5.0.
\wxheading{Derived from}
\arg{mirror} specifies if we do mirror (if it is \true) or not (if it is
\false).
-