Re: Columns vs fields in GtkTreeView

[Dave Malcolm <david davemalcolm demon co uk>]

On Sat, 2004-02-14 at 01:04, Murray Cumming wrote:
> On Wed, 2004-02-11 at 02:30, Dave Malcolm wrote:
> > I couldn't see this in the archives, so here goes:
> > 
> > I believe that the current tree/list API is unnecessarily hard to
> > understand because of the potential for confusion between columns in the
> > view and columns in the model.
> 
> This is a bit easier in gtkmm, because we have Gtk::TreeModel::Column
> objects that store the type and index.

Ah - that would make things easier.

>  
> I also try to always write "model column" and "view column" in the docs,
> and never just "column" to avoid confusion.
> 
> > So I propose that the "columns" in the model (and the various store
> > classes) get renamed to "field".
> 
> I think that would just make things more difficult, personally.

Especially for maintainers of language bindings :-)

Oh well, it sounds like other people aren't too interested.  Looking at
things, I suspect that "column" does make better sense when writing
arbitrary GtkTreeModel subclasses, rather than reusing the Store
classes.

> >   That way "columns" only refers to
> > columns in the view.  I've been using this in my own code, and it
> > clarifies things when you have more than one column in the model per
> > column in the view, and when you have "hidden columns" - it's suddenly a
> > lot clearer that these two concepts called "column" aren't the same
> > thing.
> > 
> > Obviously this would be a pain of an API change (maybe for GTK 3?).  So,
> > as a simpler change, we could merely update the docs and sample code to
> > use this terminology.
> > 
> > Here's the sample code from the docs adapted to use the proposed new
> > terminology:
> > 
> > enum
> > {
> >    TITLE_FIELD,
> >    AUTHOR_FIELD,
> >    CHECKED_FIELD,
> >    N_FIELDS
> > };
> > 
> > void
> > populate_tree_model (GtkTreeStore *store)
> > {
> > 	GtkTreeIter iter1;  /* Parent iter */
> > 	GtkTreeIter iter2;  /* Child iter  */
> > 
> > 	gtk_tree_store_append (store, &iter1, NULL);  /* Acquire a top-level iterator */
> > 	gtk_tree_store_set (store, &iter1,
> >         	            TITLE_FIELD, "The Art of Computer Programming",
> >         	            AUTHOR_FIELD, "Donald E. Knuth",
> >         	            CHECKED_FIELD, FALSE,
> >         	            -1);
> > 
> > 	gtk_tree_store_append (store, &iter2, &iter1);  /* Acquire a child iterator */
> > 	gtk_tree_store_set (store, &iter2,
> >         	            TITLE_FIELD, "Volume 1: Fundamental Algorithms",
> > 	                    -1);
> > 
> > 	gtk_tree_store_append (store, &iter2, &iter1);
> > 	gtk_tree_store_set (store, &iter2,
> >         	            TITLE_FIELD, "Volume 2: Seminumerical Algorithms",
> > 	                    -1);
> > 
> > 	gtk_tree_store_append (store, &iter2, &iter1);
> > 	gtk_tree_store_set (store, &iter2,
> >         	            TITLE_FIELD, "Volume 3: Sorting and Searching",
> > 	                    -1);
> > }
> > 
> > void
> > setup_tree (void)
> > {
> >    GtkTreeStore *store;
> >    GtkWidget *tree;
> >    GtkTreeViewColumn *column;
> >    GtkCellRenderer *renderer;
> > 
> >    /* Create a model.  We are using the store model for now, though we
> >     * could use any other GtkTreeModel */
> >    store = gtk_tree_store_new (N_FIELDS,
> >                                G_TYPE_STRING,
> >                                G_TYPE_STRING,
> >                                G_TYPE_BOOLEAN);
> > 
> >    /* custom function to fill the model with data */
> >    populate_tree_model (store);
> > 
> >    /* Create a view */
> >    tree = gtk_tree_view_new_with_model (GTK_TREE_MODEL (store));
> > 
> >    /* The view now holds a reference.  We can get rid of our own
> >     * reference */
> >    g_object_unref (G_OBJECT (store));
> > 
> >    /* Create a cell render and arbitrarily make it red for demonstration
> >     * purposes */
> >    renderer = gtk_cell_renderer_text_new ();
> >    g_object_set (G_OBJECT (renderer),
> >                  "foreground", "red",
> >                  NULL);
> > 
> >    /* Create a column, associating the "text" attribute of the
> >     * cell_renderer to the first field of the model */
> >    column = gtk_tree_view_column_new_with_attributes ("Author", renderer,
> >                                                       "text", AUTHOR_FIELD,
> >                                                       NULL);
> > 
> >    /* Add the column to the view. */
> >    gtk_tree_view_append_column (GTK_TREE_VIEW (tree), column);
> > 
> >    /* Second column.. title of the book. */
> >    renderer = gtk_cell_renderer_text_new ();
> >    column = gtk_tree_view_column_new_with_attributes ("Title",
> >                                                       renderer,
> >                                                       "text", TITLE_FIELD,
> >                                                       NULL);
> >    gtk_tree_view_append_column (GTK_TREE_VIEW (tree), column);
> > 
> >    /* Last column.. whether a book is checked out. */
> >    renderer = gtk_cell_renderer_toggle_new ();
> >    column = gtk_tree_view_column_new_with_attributes ("Checked out",
> >                                                       renderer,
> >                                                       "active", CHECKED_FIELD,
> >                                                       NULL);
> >    gtk_tree_view_append_column (GTK_TREE_VIEW (tree), column);
> > 
> >    /* Now we can manipulate the view just like any other GTK widget */
> >    ...
> > }
> > 
> > Thoughts?  Do other people think this is better?  Should I make a patch for the docs and samples?  
> > 
> > 
> > 
> > _______________________________________________
> > gtk-devel-list mailing list
> > gtk-devel-list gnome org
> > http://mail.gnome.org/mailman/listinfo/gtk-devel-list