New widget: adaptive view switcher

GtkStack children can have an icon-name property which doesn't have dedicated accessors, it can be set via gtk_container_child_set() or via the packing properties of a GtkBuilder file: https://developer.gnome.org/gtk3/stable/GtkStack.html#GtkStack--c-icon-name

This would allow to make these widgets as proper GtkStack switchers.

To whoever is going to take care of this, remember to also use the needs-attention child property: https://developer.gnome.org/gtk3/stable/GtkStack.html#GtkStack--c-needs-attention

mentioned in merge request !180 (merged)

closed via merge request !180 (merged)

closed via commit 8c497aec

reopened

Just some passing thoughts that may help someone:

Also remember to respect direction for horizontal SwitcherItem

@zbrown How is the switcher progressing? I tested your branch and it seems to work well already. I will need it pretty soon to finish the preferences window. :)

@zbrown If you don't have time to work on it please tell me so I take over your work as I will need this widget very soon for HdyPreferencesWindow. :)

@adrien.plazas Yes, sorry life has got busy for me recently

Pushed my latest changes if you can polish it off, will be nice to see it used

I really don't like how the custom css is loaded at the moment, not sure what the best solution is there

Hopefully my comments make some sense to explain what's happening

@adrien.plazas Yes, sorry life has got busy for me recently

No need to apologize, it's normal. :)

Pushed my latest changes if you can polish it off, will be nice to see it used

Great! I'll check that out. :D

I really don't like how the custom css is loaded at the moment, not sure what the best solution is there

I don't know what you talk about exactly, but regarding style changes the best is likely to submit thm to Adwaita, even if it means having to depend on a newer version of GTK.

On Matrix we discussed a widget that could contain the header bar's switcher and the window title to display when the action bar is visible. I think I found a nice way to implement that widget.

That widget would be a container able to contain any number of children. It would display only one of its children at a time, and potentially transitioning with a crossfade animation. The order of its children would matter as it would display the first of its children that fits into its available size. Its size request would be the one of its smallest child. If a child's size is larger than its previous sibbling's, it will simply be ignored and won't be displayed, regardless of the available size, as by definition there would always be a previous sibbling that fits in.

In practice, that means that if we put a switcher and a title label into such a widget and the title is larger than the switcher, the title label would simply never be shown.

The visible child would be RO-accessible, meaning that you can know when the switcher is visible and when the title is, allowing to trigger the visibility of the actionbar switcher accordingly.

Edit: I don't think such a widget could work for both orientation, so it likely should be a GtkOrientable.

Edit2: We may also want children to have arbitrary breakpoints to use in place of the minimum size to know which widget to show but which doesn't affect the size request, so the users don't have to work around this by manually setting a size request.