Hi,
Am Donnerstag, den 28.05.2009, 11:13 -0400 schrieb Caroline Kierstead:
> Sorry to bother you again, but I hit another bizarre stumbling block.
>
> > const Glib::RefPtr<Gdk::Pixbuf>
> > pixbuf = Gdk::Pixbuf::create_from_file("filename");
> > // ...
> >
>
> I managed to get this to work if I initialized the pixel buffers by
> hard-coding
> the calls as you described. Do you know why, if I switch to trying to use a
> class that returns the pixel buffers, I would get the error:
>
> (process:4209): GLib-GObject-CRITICAL **: gtype.c:2458: initialization
> assertion
> failed, use g_type_init() prior to this function
That's because of the static class data here:
> const Glib::RefPtr<Gdk::Pixbuf> DeckGUI::deck[ACE+1][SPADE+1] =
> { // Set up NINE of {DIAMOND,CLUB,HEART,SPADE}
> {Gdk::Pixbuf::create_from_file("pixmaps/card_0_0.xpm"),
> Gdk::Pixbuf::create_from_file("pixmaps/card_0_1.xpm"),
[...]
> Gdk::Pixbuf::create_from_file("pixmaps/card_5_2.xpm"),
> Gdk::Pixbuf::create_from_file("pixmaps/card_5_3.xpm") }
> };
The initialization is guaranteed to have been completed by the time
main() is entered. That implies it is also guaranteed to execute before
the Gtk::Main initialization. :-)
You need to create the pixbufs at some point after Gtk::Main has been
instantiated.
A couple of comments:
> // Holds 2-D array of pixmaps so can easily index by Faces and Suit.
> const static Glib::RefPtr<Gdk::Pixbuf> deck[ACE+1][SPADE+1];
> const static Glib::RefPtr<Gdk::Pixbuf> nullCard;
> //
Yuck. Putting objects of non-POD type into plain C arrays is almost
always a bad idea. It should work in this case, but the static
initialization won't. You may want to look at pixbuf-demo in gtkmm for
an example that creates pixbufs from a static array of filenames.
> const Glib::RefPtr<Gdk::Pixbuf> getCardImage( Faces f, Suits s );
It isn't wrong to return a const value, but pointless in most cases.
> // Initialize 4 empty cards and place them in the box.
> for (int i = 0; i < 4; i++ ) {
> card[i] = new Gtk::Image( nullCardPixbuf );
> hbox.add( *card[i] );
> } // for
[...]
> OtherWorld::~OtherWorld() {
> for (int i = 0; i < 5; i++ ) delete card[i];
> } // OtherWorld::~OtherWorld()
You can avoid the manual (and unsafe) memory management by taking
advantage of container ownership:
hbox.add(*Gtk::manage(new Gtk::Image(pixbuf)));
This works for all non-toplevel widgets.
> const Glib::RefPtr<Gdk::Pixbuf> DeckGUI::nullCard =
> Gdk::Pixbuf::create_from_file("pixmaps/cardback2.xpm");
Any particular reason why you're using the obsolete XPM format? It
isn't a big deal, but I suspect you might be using XPM only because it
used to be the standard image format for X applications, ages ago.
Oh, and please always carbon-copy to the mailing list when you're
replying.
Cheers,
--Daniel
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