Re: need pointers for working with custom Gtk widgets ...

[Lars Clausen <lars raeder dk>]

On Thu, 2007-02-01 at 17:44 +0530, Sameer Sahasrabuddhe wrote:
> Hello,
> 
> I have been working on bug 60331 ("Object properties should handle
> multiple objects")
> 
> http://bugzilla.gnome.org/show_bug.cgi?id=60331
> 
>  ... the basic idea is to make the properties dialog keep track of
> which properties have been changed by the user. In order for this to
> work, every widget in the dialog needs to register the default
> signal_handler for suitable signals.

Yay!  I'm happy to hear this.

> But the problem is lib/prop_attrs.c ... for custom widgets, it is
> difficult to decide which signals need to be connected. For example,
> linestyleprop_get_widget() creates a custom widget called
> DiaLineStyleSelector, using the function dia_line_style_creator_new().
> The pointer returned by this function is for a GtkWidget. Can this be
> cast back into DiaLineStyleSelector? Or even better, can a pointer to
> the custom widget be returned instead of a generic GtkWidget* ? How
> does one do this in Gtk?

The standard appears to be that the _new() functions return a GtkWidget
that you then cast back, see http://gtk.org/tutorial/x2202.html --
though not all standard Gtk widgets follow this, though there may be a
reason behind that.

-Lars