+\func{bool}{Union}{\param{const wxBitmap\&}{ bmp},
+ \param{const wxColour\&}{ transColour = wxNullColour},
+ \param{int}{ tolerance = 0}}
+
+Finds the union of this region and the the non-transparent pixels of a
+bitmap. If the bitmap has a mask then it will be used, otherwise the
+colour to be treated as transparent may be specified, along with an
+optional colour tolerance value.
+