Re: Adding a child widget to a custom widget

[Tristan Van Berkom <tvb gnome org>]

Alexandre wrote:
>   Hi
>
>   I'm creating a widget, a plotting widget, and I have done a scale widget too. So, I want that the plotting 
> widget has a child, the scale widget, to be it's axis.
>   So, I fill the "allocation" structure of the scale widget to the position I want, and then I call 
> gtk_widget_set_parent           (scale, plot). But It doesn't works, the expose function of the scale widget is never 
> called (neither the realize, configure.. and the others I think).
>
> I don't know if it's the right procedure to add a child widget..
>
> If someone could help me, I would be glad.

Hi Alexandre,
    Parenting a widget is not a simple matter of setting the values
of a childs allocation struct, you should never man-handle widget structures
like this - your container widget must properly implement the GtkContainer
interface (which, for your added confusion - is actually implemented as
an abstract class and not an interface, but thats besides the point...).

Your best bet is to look at the gtk+ code for a container that works
similar to how your container will work and then borrow the groundworks,
for example - you must implement ->forall(), ->add(), ->remove() etc...
you must gtk_widget_size_allocate() some screen realestate for your children
when your container widget is resized etc.

Cheers,
                      -Tristan