I am extremely annoyed to realize that it is IMPOSSIBLE to find the basic colors of the #Gnome interface in #GTK v4.

@metal3d the default GTK4 theme does not provide any source of stability for the colors, mostly because it never did, not even in GTK2 or GTK3; libadwaita, on the other hand, does: https://gnome.pages.gitlab.gnome.org/libadwaita/doc/1-latest/named-colors.html

@metal3d but if you want to *draw* with CSS colors, then you need to use the gtk_render_* API in GTK3, and the GtkSnapshot API in GTK4. That has been the case since GTK 3.0. The old "ask the style machinery for a color" made sense in GTK2, where you only had colors. With the introduction of CSS, you can have gradients, textures, blended layers, or (most likely) a transparent value. There is no "color" to be queried in many cases.

@metal3d It's not a case of being "better" or "worse" (though CSS allows us to do better rendering without loading shared modules that literally put pixels inside widgets, like GTK2 engines did); it's a case of being an entirely different API.

@ebassi that's not to draw on GTK. That's to get the theme generic colors (background and foreground) to color an app using another library (fyne.io).
There is no dark/light information on gnome and nothing to get the theme base colors.
Actually I call some gjs command to get a invisible one shot window color from get_context() method. Grk4 abandoned this.

@ebassi that's something that I don't understand... OK, css is cool to make whatever we want for themes. But there are at least 2 needed information, the "dakmrk/light" switch and "foreground/background" colors. That's anormal to have to call GJS (or python) from another language/lib to find this. And anormal that now it's impossible to get these information.

@ebassi sorry for my English and sorry if I'm a bit annoyed but I spent hours to read documentation about GTK 4 to finally realize that I will not be able to continue my idea...

@metal3d I understand the annoyance, but really: what you want to achieve was never supported in 20+ years, and it's not really supportable programmatically.

At most, you can emulate the appearances of libadwaita by looking at the generated CSS, and by using the documentation; for anything else, you'll have to use the good old Eyeball Mk 1, or the GTK inspector, and then emulate the result.

@ebassi the goal is to be able, from fyne app (in go) to get information about the current gnome theme colors. Not to get the Css file or attributes with inspector to create the theme by hand.

@ebassi as the fyne app is absolutely cross platform (even with android) and statically compiled, I need a way, even by command line, to get at least the 2 majors colors. GJS was enough (with get_context().get_background_color()) with a fake window. That was really enough even if it's not very efficient.

@metal3d at most you can use get_context().lookup_color("window_bg_color"), but that requires libadwaita.

Same if you want the light/dark information: you need libadwaita or libhandy, or you need to watch the system setting yourself—GTK by itself does not have a light/dark default theme.

@ebassi get_context isn't implemented in grk4. You said that I can use it with libawaita but... I don't find how at this time

@metal3d I have no idea what's "grk4", but in GTK4 you still have access to the GtkStyleContext of a GtkWidget: https://docs.gtk.org/gtk4/method.Widget.get_style_context.html

Then you can use GtkStyleContext.lookup_color() with a named color: https://docs.gtk.org/gtk4/method.StyleContext.lookup_color.html

The named colors are documented in libadwaita: https://gnome.pages.gitlab.gnome.org/libadwaita/doc/1-latest/named-colors.html

@ebassi that returns default colors, not the colors that are defined in the currently used theme.
That was OK with GTK3 - a pitty

@metal3d There's no such thing as a "default color". Those colors are the ones currently used by libadwaita, if you use the names defined by libadwaita. Otherwise you need to know the names defined by the Default theme; the Default GTK theme is not API. Of course, any other theme can define its own colors.

At this point, I have *no idea* what you're expecting. Instead of using Masto, you may want to use Discourse: https://discourse.gnome.org/tag/gtk

@ebassi i only expect to be able to get the default font color and whatever I can get for the background of a basic window (the Css would be OK. The Css as string is enough) from a basic GTK.window. This to automatically replicate enough of the style to an app style which is not built in gtk.