* fix(theme): complete Linux System appearance tracking
Follow up on #881 for #446 with the standard numeric appearance portal setting
and event-driven updates that wake idle windows. Keep manual modes independent,
cache their desktop updates without repainting, and cancel the worker on close.
Retain inherited native window appearance and populate both egui style branches
with the chosen palette. Preserve saved System, the Light default and unknown
source fallback, and avoid desktop session access in headless UI contexts.
Assisted-by: Codex (gpt-6.1-sol)
* Desktop theme: keep the GNOME colour-scheme fallback XFCE needs
The portal tracker read only org.freedesktop.appearance, which XFCE's portal
doesn't answer (it proxies the GSettings schemas). It now also reads and
subscribes to org.gnome.desktop.interface color-scheme and uses it when the
freedesktop setting states no preference, as main's reader did. KDE answers
only the freedesktop one, which wins when it states a preference.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---------
Co-authored-by: Brandon Thomas <echelon@gmail.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
winit reports no system theme on Linux — `ActiveEventLoop::system_theme` is
`None` there on every desktop — so `ThemePreference::System` never saw the
desktop's choice and silently fell back to whatever was on screen: PdfCraft
came up light on a dark desktop, and picking "Use system setting" after Dark
kept it dark. The default setting did not follow the system.
`pdfcraft-platform` now reads the XDG Desktop Portal's Settings interface off
the UI thread and the app follows the answer, including a change made while it
runs. The colour scheme is asked for under its GNOME schema name first, which
GNOME's and XFCE's portals both answer, then under the older freedesktop one,
which KDE answers. A desktop that answers neither leaves the user's own choice
alone, exactly as before.
Co-authored-by: GyuriX <gyurix@users.noreply.github.com>
