Re: Displaying simple HTML in gtkmm app

[Murray Cumming <murrayc murrayc com>]

On Fri, 2005-03-25 at 10:45 +0000, Chris Vine wrote:
> On Friday 25 March 2005 06:03, John Taber wrote:
> > Chris,
> >
> > On Thursday 24 March 2005 16:01, you wrote:
> > > What more do you want to know?
> >
> > Please realize some of us are application developers coming from other non
> > programming disciplines so for me, a couple of code lines are worth a
> > thousand words - here is the example of where I was working from
> >
> > > > > gtkhtml *cview;
> > > > > Gtk::Frame *mmview = new Gtk::Frame();
> > > > > mmview->wrap(cview);
> > > > > mmview->...... // whatever gtkhtml method
> > >
> > > Pass a pointer to the GTK+ object to be wrapped as the argument to
> > > Glib::wrap(), and Glib::wrap() returns a pointer to the resulting wrapped
> > > gtkmm object.
> >
> > so trying to apply what you indicate here I come up with this:
> > gtkhtml *cview;
> > Gtk::Frame *mmview = Glib::wrap(cview);
> > mmview->...... // whatever gtkhtml method
> >
> > does this look right ? I just picked out Frame - not sure how to pick a
> > gtkmm object to wrap into.  Also, I wonder if I first have to instantiate
> > the gtkmm object like:
> > Gtk::Frame *mmview = new Gtk::Frame();
> > mmview = Glib::wrap(cview);
> >
> > thks John
> 
> John,
> 
> This will not work.  You can only wrap a GTK+ object to provide the 
> corresponding gtkmm object.  Thus a GtkFrame object wraps to a Gtk::Frame 
> object, a GtkLable object wraps to a Gtk::Label object, and so on, so your 
> code above won't work (it should fail to compile).

It would compile, but it would obviously forget the first mmview
instance. That should be obvious C++.

> An example is this:
> #include <gtk/gtkframe.h>
> #include <gtkmm/frame.h>
> GtkWidget* frame = gtk_frame_new(0);
> Gtk::Frame* wrapped_frame = Glib::wrap(GTK_FRAME(frame));
> 
> wrapped_frame is now pointing to a standard Gtk::Frame object.  You can get 
> back to the underlying C object from it (as with any other gtkmm object) with 
> wrapped_frame->gobj();
> 
> I do not really know anything about gtkhtml, but I do not think there is a 
> corresponding gtkmm-compatible C++ class wrapping it, so your approach will 
> not work. 

It will create the most-derived base class that it knows about, and
you'll have to use GTK+ C function calls, with gobj(), for the rest. Or
wrap it using gmmproc.
 
>  If you need to put a gtkhtml object in a gtkmm container, the best 
> bet would probably be to put it in the equivalent GTK+ container first 
> (assuming that that is possible with gtkhtml and GTK+), and wrap the GTK+ 
> container to form the equivalent gtkmm container.  You can put the gtkmm 
> container anywhere in gtkmm which excepts that container type.
> 
> The disadvantage is that you will have to learn some GTK+ coding to do it (but 
> that will come in handy anyway).

-- 
Murray Cumming
murrayc murrayc com
www.murrayc.com
www.openismus.com