[HELP] Struggling to make custom widget implement Scrollable

[LittleHuba]

I have the following attempt to subclass a widget with some interfaces. One of those interfaces is Scrollable.

glib::wrapper! {
    pub struct CustomViewport(ObjectSubclass<imp::CustomViewport>)
    @extends Widget,
    @implements Accessible, Buildable, ConstraintTarget, Scrollable;
}

But if I check in the GTK Inspector what interfaces my widget implements, I only see Accessible, Buildable, ConstraintTarget but not Scrollable.

Is there something I'm doing wrong?

[bilelmoussaoui]

The @implements part of glib::wrapper! only implements the IsA traits. If you want your type to be a Scrollable, you have to write something like impl ScrollableImpl for CustomViewport {} in the imp module and providing the required vfuncs. You would also need to override certain properties, see https://gitlab.gnome.org/World/obfuscate/-/blob/master/src/widgets/drawing_area.rs?ref_type=heads#L54 for a full example