Do not use color properties directly

[tintou]

They are being copied when retrieving as they are simple structs.
Closes #1243

[JoseExposito]

Is the same change required in Background.load_pattern ()?

By the way, tested with latest Mutter 👍

[davidmhewitt]

To be honest, this binding felt a lot better when Clutter.Color.from_string just returned a Clutter.Color, even if it did hide the boolean (that we don't use anyway). It felt like a "constructor", like all the other from_x methods that exist across GLib libraries.

What I don't understand is how these bindings are being generated because of this:

gala/vapi/Clutter-9.metadata

Line 119 in 837fb56

color_from_* skip

If those symbols are skipped and I can't find anywhere they're manually re-added, why are they in the bindings at all?

Edit: Additionally, this is still bound in the old way in Clutter vapi that's not part of the Mutter tree:
https://valadoc.org/clutter-1.0/Clutter.Color.Color.from_string.html

And, in GJS they have it bound so that from_string returns a Clutter.Color (as well as the boolean, which we can't do in Vala):
https://gitlab.gnome.org/GNOME/gnome-shell/-/blob/main/js/ui/background.js#L342

But this just me saying I'm in favour keeping it as it was before the bindings change, just so we can keep it as a one liner in Gala.

[tintou]

@davidmhewitt I've changed the .metadata and -custom.vapi to reflect the API you wanted here, makes things easier

fixed

[JoseExposito]

I was experimenting crashes when changing the wallpaper and I though it was because of this change, but no, this code is fine.

After bisecting it looks like the problem was introduced in 4aec79a

Merging this branch, as it works as expected both with elementary's Mutter and Fedora's Mutter, and I'll try to fix the crash.