Record: single-window handler and its icon

Outcome

The handler is now a single window with one large output area, it has its own AppImage icon, and the AppImage MIME types use that same icon.

Is There an Icon for the AppImage Standard?

There is no icon defined by the AppImage file-format specification. The specification defines magic bytes, a payload, and an AppDir; it says nothing about an icon for the file type.

Three related icons do exist:

• The AppImage project has a project logo, shipped with AppImageKit, AppImageLauncher, and the runtime; it identifies the project rather than the file type.
• The shared MIME database gives the AppImage types a generic icon; the definition this host had used <generic-icon name="application-x-executable"/>, which is why an AppImage looked like any other executable.
• Every AppImage carries its own application icon for the application it contains, which is unrelated to the file type.

Decision: the handler now ships an original mark of its own, sources/tools/icons/appimage-handler.svg. It is a self-contained package with a run control, so it reads as “an AppImage you can run”, and it avoids reusing the AppImage project’s logo.

The Icon Is Wired In Three Places

The MIME rewrite is reversible: the original file is copied to the tool’s backup/ directory before the edit and restored by handler uninstall, which also removes the installed icon. Re-registering our own handler no longer overwrites the real previous defaults it recorded; the manifest keeps the original appimagelauncher.desktop values.

The Single Window

• Header: the application name, then version and GenericName, then Comment.
• Details: File, Size, and Will install as. Type, Payload, and Embedded entry were removed as requested.
• Buttons: Run once, Integrate, Inspect, Close, directly below the details block.
• Output: one large monospaced text area below the buttons, taking the remaining height, empty at first.
• Inspect writes the full AppImage report into that area.
• Integrate writes the conflict list there first, then switches the buttons to Back, Add alongside, and Replace existing, and writes the install result there.
• Run once now reports the start line in the text area instead of only a desktop notification.
• The old separate Inspect, conflict, and result windows are gone.

Centring

The window is centred where the platform allows it. center_window computes the centre of the monitor work area and applies it with xdotool on X11. Wayland does not let a client choose its position, so there the call is a no-op and the compositor places the window; GNOME centres a new toplevel window by default.

Verification

Verified 2026-09-22 with make test; all fifteen test scripts passed.

• tests/95-handler-ui.sh now also registers the handler in an isolated XDG home and asserts: the entry contains Icon=appimage-handler, the icon is installed into the theme, the MIME generic icon is rewritten, and handler uninstall removes the entry and icon and restores the original MIME icon.
• On the real desktop, verified after make install and handler install: the entry carries Icon=appimage-handler, the icon is present and mode 644, both AppImage MIME types name appimage-handler, and the manifest still records the original appimagelauncher.desktop defaults.
• The GTK layout and centring could not be exercised headlessly; they are verified by compilation, import, and dispatch.

Commits

• cda59a3 feat: single-window handler with an AppImage icon, tied to the AppImage MIME types