You used the term "Value Semantics" a lot in the last e-mail. What are value semantics?
Daniel Elstner wrote: > Am Mittwoch, den 06.05.2009, 13:42 -0400 schrieb Christopher Harvey: > >> I want to extend Gdk::Region. I noticed it didn't have a virtual >> destructor. I REALLY need to be able to extend it, otherwise I'll end up >> with random functions floating around all over the place. >> > > A virtual destructor probably won't be of much help, as Gdk::Region > implements value semantics so you can't really add any data to it and > use it polymorphically. > > If you only want encapsulation but don't like the idea of inheriting > from a class that doesn't have a virtual destructor, you could instead > make Gdk::Region a member of your custom class. > > >> Basically I want to create a region class that can build itself from >> complex input, then be used as a normal region. >> > > I don't know what you are working on; however, from your other mail it > sounds as though you are trying to reduce the amount of drawing done in > your expose handler. If so, it's probably a good to check whether > complicated regions will actually improve matters on average. With > Cairo clipping, it can easily happen that figuring out the clipping > region actually increases the overall processing time. It depends on > what and how much you are drawing, I guess. > > >> Can we make this class extendable? It seems like a nice feature for a >> widget library especially. >> > > Adding a virtual destructor probably wouldn't be a big deal here (but > not until the next ABI break!). However, I'm not sure it will be of any > use, given the value semantics. > > --Daniel > > > > _______________________________________________ gtkmm-list mailing list [email protected] http://mail.gnome.org/mailman/listinfo/gtkmm-list
