(rect.x >= 0) && (rect.y >= 0) &&
(rect.x+rect.width <= GetWidth()) &&
(rect.y+rect.height <= GetHeight()),
wxNullBitmap, wxT("Invalid bitmap or bitmap region") );
wxBitmap ret( rect.width, rect.height, GetDepth() );
(rect.x >= 0) && (rect.y >= 0) &&
(rect.x+rect.width <= GetWidth()) &&
(rect.y+rect.height <= GetHeight()),
wxNullBitmap, wxT("Invalid bitmap or bitmap region") );
wxBitmap ret( rect.width, rect.height, GetDepth() );