Freeciv

As far as I can tell, these handles are just GtkToggleButtons, without anything particularly special for theming engines to select on. (In Gtk2 and Gtk3.)

On my system, I can get them a bit smaller by hacking with the CSS: if I start
GTK_DEBUG=interactive inst/bin/freeciv-gtk3
and then enter this hack on the "CSS" tab of the debug window:
button.toggle { padding: 0px 0px 0px 0px; }
I can get them down from 36px to 18px wide. Reducing "margin" (space outside control) to 0px makes no difference. Reducing "border-width" to 0px only saves a couple of pixels. "Objects" tab doesn't show any interesting objects inside the GtkToggleButton.

I notice that data/themes/gui-gtk-3.0/Freeciv/gtk-3.0/gtk.css is setting these:

-GtkButton-default-border: 1;
-GtkButton-default-outside-border: 2;

But the Gtk3 docs say they

...been deprecated since version 3.14 and should not be used in newly-written code.
Use CSS margins and padding instead; the value of this style property is ignored.

And indeed with my Gtk3.24.5 I get these runtime warnings (among many others):

(freeciv-gtk3:12531): Gtk-WARNING **: 15:59:37.988: Theme parsing error: gtk.css:5:29: The style property GtkButton:default-border is deprecated and shouldn't be used anymore. It will be removed in a future version

(freeciv-gtk3:12531): Gtk-WARNING **: 15:59:37.988: Theme parsing error: gtk.css:6:37: The style property GtkButton:default-outside-border is deprecated and shouldn't be used anymore. It will be removed in a future version

I wonder if this has anything to do with the behaviour difference between old and new Gtk libraries -- perhaps we were somehow relying on these properties and they are no longer doing anything?

Modifying my CSS hackery to

button.toggle { padding: 0px 0px 0px 0px; min-width:6px; }

gets me controls that are 8px wide, including the border.

I think the way to productionise this is probably to put some special selectable property on the button created by detached_widget_fill(), and attach the above style to it in gtk.css.

I no longer have any direct ability to build and test against old Gtk3, so I guess the way to find out how it affects that will be to commit it and test the next msys1 build.

and attach the above style to it in gtk.css

That doesn't work for people who want to use a system theme. (Also, I can't figure out how to make it work.)

I suspect instead I should add it with some gtk_style_context_add_provider_for_screen() faff, like gui_update_font(). (Hopefully that will be overrideable with themes if anyone cares to.)

With this patch and GTK_DEBUG=interactive, entering this in the debugger CSS tab:

.detach_button {
  min-width: 10px;
}

did cause the detach handles to grow wider again, so I'm reasonably confident that a custom theme could override the embedded CSS if it tried hard enough.

There's a bunch of stuff in our Gtk3 gtk.css that I can't square with the docs (like .button selector syntax), so I don't know what it's meant to do; and with Gtk 3.24.5 I get a bunch of deprecation warnings about stuff in gtk.css. Perhaps that stuff is being ignored on my system, and not on older systems, and interacts with my new styling in some bad way.

...if this drags on, perhaps I'll need to split out the Gtk3.22 patch? That should be safe, right?

Jacob Nevins wrote:

...if this drags on, perhaps I'll need to split out the Gtk3.22 patch? That should be safe, right?

At least it's promising that Ubuntu Bionic (gtk+-3.22.30) gtk3.22-client works with the patch, though it didn't have the original issue without. So broken "before" state is not a prerequisite for the patched version to work. It seems the patch can be used with both gtk+-3.22 and gtk+-3.24 that are the only versions that gtk3.22-client may use.

This causes gtk3x-client compile error.

../../../../src/client/gui-gtk-4.0/gui_main.c: In function ‘detached_widget_fill’:
../../../../src/client/gui-gtk-4.0/gui_main.c:878:5: error: too many arguments to function ‘gtk_css_provider_load_from_data’
878 | gtk_css_provider_load_from_data(detach_button_provider, | ^_~~~~~~~~~~~~~~~~~~~~~~~~~~~~

While it's not going to completely resolve this ticket, I got an idea that maybe our configure should informa a user who has gtk+-3.22 / 3.24, but does --enable-client=gtk3 anyway that gtk3.22-client might be better suited for them.