// create a subimage from a native image representation
virtual wxGraphicsBitmap CreateSubBitmap( const wxGraphicsBitmap &bitmap, wxDouble x, wxDouble y, wxDouble w, wxDouble h );
// create a subimage from a native image representation
virtual wxGraphicsBitmap CreateSubBitmap( const wxGraphicsBitmap &bitmap, wxDouble x, wxDouble y, wxDouble w, wxDouble h );