+ virtual void paintWindowDecoration(eWindow *wnd, gPainter &painter, const std::string &title) = 0;
+ virtual void paintBackground(gPainter &painter, const ePoint &offset, const eSize &size) = 0;
+ virtual void setForegroundStyle(gPainter &painter) = 0;
+ virtual void drawButtonFrame(gPainter &painter, const eRect &frame) = 0;
+ virtual ~eWindowStyle() = 0;