Runic.Platform.Linux 0.9.1

Runic.Platform.Linux (GTK 3)

The GTK 3 window services for Linux x64: portal file dialogs and file handoff with GTK 3 parenting, and the GTK 3 text clipboard. The package has no public API. Runic.Application.Views.Desktop selects it for GTK 3 windows from DesktopPlatformServices.ForWindow and services.AddRunicPlatformServices(), and never in a GTK 4 process, which Runic.Platform.Linux.Gtk4 serves. The package references the shared runtime and no Desktop, ASP.NET Core, Windows or macOS assemblies; creating its services does not initialize GTK or load native libraries.

The file dialogs are direct XDG portal dialogs with GTK 3 X11/Wayland parent export. The desktop chooses the portal backend, so Plasma can show KDE's picker. A failed parent export never opens an unparented window, and a missing portal never triggers an implicit toolkit fallback.

The portal dialogs also serve Flatpak and Snap applications. Saves are atomic, including through a Flatpak document view; see portal behavior. A session bus, GTK3, a display and the appropriate portal backend must be installed.

The clipboard serves UTF-8 text with GTK selection ownership. Read limits bound managed decoding and string allocation; GTK itself receives the native selection before reporting its byte length. No offered UTF8_STRING target returns null, while an offered empty target returns an empty string. A failed advertised transfer reports Other. GTK does not expose a separate permission code for transfer refusal. Concurrent access reports ResourceBusy. A successful write means GTK acquired ownership; it does not promise clipboard-manager persistence when the application exits. Write cancellation is checked before acquisition and cannot replace the actual result once acquisition starts.

Dispose the clipboard while the presentation dispatcher still runs. Disposal drains pending selection callbacks and releases only this instance's current ownership. Cancellation drains GTK's callback before completing; it does not revoke native callback memory. The embedding host must keep its GTK event loop alive until drain finishes. External clipboard owners can delay responses according to GTK's native selection timeout.

Xvfb tests cover X11 mechanics only. Actual selected-file, Wayland/portal, keyboard, Orca, IME, scaling and installed-app evidence is required separately; this package does not claim those gates passed from a headless test. Directory selection and persisted portal grants are outside the preview contract.