Re: How to add a custom cell renderer to a Gtk::IconView

[Todor Todorov <ttodorov gmx net>]

Thanks again for the reply.

It is not a problem to implement the renderer in gtkmm - as a matter of 
fact that's the first thing I did. As you know though, I can't add it to 
a Gtk::IconView, because it does not implement the CellLayout interface. 
That bit of info was in your first reply.

I guess I will have to look into subclassing Gtk::IconView itself ... Do 
you know of any examples for that? I suspect deriving from Gtk::ListView 
will be easier, and I'll find more code I could look up and take a note 
from, but I have no idea how to make the new class order the items in 
multiple columns.

Best regads,

Todor

On 11/22/2009 05:20 AM, Jos Alburquerque wrote:
> On Fri, 2009-11-20 at 23:59 -0500, Todor Todorov wrote:
>    
> > Thanks for the reply. I only recently subscribed to the list and need
> > yet to find a searchable archive online, with somewhat usable
> > interface... Anyway, I really appreciate your time in helping me solve
> > this problem.
> >      
>    
> > > From the main gtkmm page[1], select the Mailing Lists link.  The "List
> >      
> Archives" section provides links to searchable archives.
>
> [1] http://www.gtkmm.org/index.shtml
>
>    
> > The only thing I don't know how to do is how to adapt the C/gtk+
> > renderer to the gtkmm/sigc signal-slot mechanism. My custom renderer has
> > a vfunc declared in the (gtk+ _class) struct as:
> >
> > void ( *toggled )( GtkCellRendererThumb* renderer, gchar* path, gpointer
> > data );
> >
> > I obviously need it in order to tell the model when a thumbnail in my
> > icon view has been permanently selected via its checkbox.
> >      
> It should be possible to wrap the renderer object in a Gtk::CellRenderer
> casting it to a GtkCellRenderer and using Glib::wrap().  Using the
> standard Gtk::Renderer signals would then be possible.  On the other
> hand, you could also implement your renderer in C++.  There are two good
> good examples of how to do that here:
>
> http://git.gnome.org/cgit/gtkmm-documentation/tree/examples/others/cellrenderercustom
>
>    
> > I tried the
> > following:
> >       ...
> >       Gtk::IconView *browser = 0;
> >       builder->get_widget( "browser", browser );
> >       {
> >           GtkIconView *view = browser->gobj();
> >           GtkCellRenderer *cell = gtk_cell_renderer_thumb_new();
> >           gtk_cell_layout_pack_start( GTK_CELL_LAYOUT( view ), cell, FALSE );
> >           g_object_set( cell, "thumb-checkable", TRUE, "xpad", 2, "ypad",
> > 2, NULL );
> >           gtk_cell_layout_set_attributes( GTK_CELL_LAYOUT( view ), cell,
> >                                           "thumb-name", 0, "thumb-date", 1,
> >                                           "thumb-image", 2,
> > "thumb-checked", 3,
> >                                           "thumb-duplicate", 4, NULL );
> >           g_signal_connect( G_OBJECT( cell ), "toggled", G_CALLBACK(
> > &MainWindow::on_thumbnail_checked ), NULL );
> >       }
> >       browser->set_model( thumblist );
> >       ...
> >
> > The callback is a member function declared as
> >
> > void on_thumbnail_checked( GtkCellRendererThumb* renderer, gchar* path,
> > gpointer data )
> > {
> >       std::cout<<  "test, path is "<<  path<<  std::endl;
> > }
> >
> > Everything works up to the call of the function. It is called once, the
> > first time one of the thumbnails is activated, and it prints out "test,
> > path is".
> > Any subsequent click on a thumbnail does not trigger the callback,
> > although the activate function of the renderer itself is called every
> > time - verified thorugh g_print statements, which print out the tree
> > path as well....
> >      
> Maybe the signal emission implementation in you renderer class is a
> little off.  If the callback function is called once then it seems that
> the mechanism does work, just not exactly as desired.  The logic may
> need a little consideration.  For example, does the logic of the
> renderer class dictate that the signal be emitted when the checkbox is
> toggled? only selected?  Is the class designed so that the signal is
> emitted when the icon is clicked? etc.  It's hard to know for certain
> but these are just ideas to possibly help get your own ideas working.
>
>