Implement xdg-desktop-portal accent-color spec

[affederaffe]

What does the pull request do?

Use the standardized xdg-desktop-portal setting to get the accent color
flatpak/xdg-desktop-portal#815

Currently, no DE actually implements it as it just got merged, hence WIP

What is the current behavior?

Accent colors only work on KDE

What is the updated/expected behavior with this PR?

Accent colors should work on every DE that provides them via the settings portal

How was the solution implemented (if it's not obvious)?

Checklist

• Added unit tests (if possible)?
• Added XML documentation to any related classes?
• Consider submitting a PR to https://github.com/AvaloniaUI/Documentation with user documentation

Breaking changes

Obsoletions / Deprecations

Fixed issues

[avaloniaui-team]

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[orowith2os]

It's fine if you remove the WIP tag, if the only reason is DEs implementing the key; the only actual requirement should be a stable xdg-desktop-portal release with the key. And even then, you can implement it without a stable release, or any release at all.

[maxkatz6]

@jmacato @kekekeks should we merge this PR now? Before actual distros support this feature. Since it's considered as a part of the standard now.

[jmacato]

PR/Concept looks good to me, although i'll wait what @kekekeks has to say

[kekekeks]

The support for the spec seems to be merged into KDE yesterday, so I'd like to wait for the next KDE Neon build to test.

Not strictly required though.

[avaloniaui-team]

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[affederaffe]

Testing it on KDE Neon, it doesn't work.
Though I think actually KDE isn't following the spec here: When changing the accent color, the SettingChanged signal is invoked with the value

   string "org.freedesktop.appearance"
   string "accent-color"
   variant       array [
         variant             double 0.0313726
         variant             double 0.611765
         variant             double 0.541176
      ]

but as per spec:

In the case that an accent color is requested, the underlying value would be a struct containing three doubles, each being an RGB value in the range of [0,1].

[jmacato]

@affederaffe could we handle that without straying out of spec? perhaps a special case for KDE? (although ik that would suck...)

[orowith2os]

@jmacato KDE should fix their portal if it's not following the spec, you shouldn't be working around their bug.

[affederaffe]

@jmacato I've asked in the KDE Plasma Matrix room to see if this is actually a spec violation or just me not reading said spec correctly. For now, I'd just wait since no DE has officially released any version that supports it anyway.

[avaloniaui-team]

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[avaloniaui-team]

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[jmacato]

@affederaffe which KDE version is the spec implemented? could i use Debian Sid for testing?

[easyteacher]

On 2023/9/16 13:14, Jumar Macato wrote: @affederaffe <https://github.com/affederaffe> which KDE version is the spec implemented? could i use Debian Sid for testing?Message ID: ***@***.***>

Plasma 5.27.8

[avaloniaui-team]

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[avaloniaui-team]

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[affederaffe]

Confirmed to work on Plasma 5.27.8 and 6, GNOME still hasn't merged the relevant PRs...
Additionally, the current solution breaks on Plasma 6, probably due to a bug on their side as far as I can tell.

[easyteacher]

Confirmed to work on Plasma 5.27.8 and 6, GNOME still hasn't merged the relevant PRs... Additionally, the current solution breaks on Plasma 6, probably due to a bug on their side as far as I can tell.

https://invent.kde.org/plasma/xdg-desktop-portal-kde/-/merge_requests/244