A Linux desktop at 125% or 150% tells X11 apps through Xft.dpi, but AWT only takes whole scales there, so the app drew at 100%: sharp but too small. That is also what JetBrains suggests for blurry fractional scaling on Wayland (JBR-10582): XWayland with KDE's "legacy apps apply scaling themselves", which only works if the app scales itself. DesktopUiScale reads Xft.dpi (XSETTINGS, then the X resource database via JNA; AMETHYST_SCALE overrides) and AppWindow and the crash dialog raise Compose's density by what AWT left out. Measured on Xvfb at Xft.dpi 120: a 1-px checkerboard stays pure black and white at the right size. LocalDensity no longer equals AWT's scale there, so the two places that converted AWT coordinates with it (fullscreen overlay origin, gutter wheel redispatch) now read the component's own AWT scale. The default window size cap scales with it. Native Wayland, macOS and Windows are unchanged. JNA (LGPL-2.1+ or Apache-2.0, used under Apache-2.0) was already shipped through nestsClient; desktopApp now declares it. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01YFyERkpgRiWgXWyc5Jg7Xa
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name: desktop-expert description: Desktop JVM shim in desktopApp/: AmethystDesktop window, DesktopMenuBar, platform ports, OS keyring; :desktopApp:run, packaging. Use when touching desktopApp, or to run/screenshot the shared UI headless (tools/desktop-run, Xvfb) to verify a UI change. NOT for writing shared screens.
Desktop (JVM shim)
desktopApp is a shim: it opens a window and renders the same AmethystApp Android renders.
Screens, the navigation shell (bottom bar / rail / drawer, chosen by ScreenLayoutSpec) and the
deck are shared UI in commonsUI — see AGENTS.md "Navigation Shell" and "Feature Workflow", and
compose-expert. Never add a desktop-only screen or a desktop-specific navigation layout.
Background: commons/plans/2026-09-27-one-ui-android-desktop.md,
commons/plans/2026-10-09-legacy-desktop-retirement.md (the legacy desktop app is gone).
Where things live (desktopApp/src/jvmMain/kotlin/com/vitorpamplona/amethyst/desktop/)
| File | Role |
|---|---|
app/AmethystDesktop.kt |
main(): macOS AWT properties, data dir, DesktopAppModules, the Window, the CompositionLocals (LocalAppPlatform, LocalNotePlatform, …) around AmethystApp. --publish-scheduled runs headless (OS timer publishing scheduled posts). |
app/DesktopAppModules.kt |
The desktop graph (Android's AppModules minus phone-only parts). |
app/DesktopAppRoot.kt |
AppRoot impl; jvmDestinations. |
app/DesktopAppPlatform.kt |
AppPlatform (commonsUI ui/platform/); unoverridden members keep the default, which hides the feature. |
app/DesktopNotePlatform.kt, DesktopRichTextPlatform.kt |
NotePlatform, RichTextPlatform (commonsUI). |
app/DesktopAccountViewModelHost.kt, DesktopLocalCacheHost.kt, DesktopAppServices.kt |
AccountViewModelHost, LocalCacheHost, AppServices (commons). |
app/DesktopMenuBar.kt |
DesktopNavigator, the Command enum, DesktopMenuBar, handleShortcut. |
app/Legacy*Import.kt |
One-time import of the retired legacy app's accounts, deck, feeds, privacy lock. |
platform/PlatformInfo.kt |
PlatformInfo.current / host, isMacOS, isWindows, isLinux, isGnome, isKde. |
platform/SavedWindowBounds.kt |
Window position/size persisted to window-bounds.properties. |
platform/WaylandDisplay.kt, platform/AppWindow.kt |
Native Wayland: WLToolkit picked in main() on a Wayland session (AMETHYST_X11=1 opts out); AppWindow is Compose's Window elsewhere and a Swing-drawn frame there. Open new top-level windows with AppWindow, never Window/ComposeDialog. |
platform/DesktopUiScale.kt |
X11 at a fractional scale (Xft.dpi 120 = 125%, AMETHYST_SCALE by hand): AWT draws whole scales only, so AppWindow raises Compose's density by the rest. LocalDensity is then not AWT's scale: convert AWT window/event coordinates with awtPixelScale(component), and size AWT windows in AWT units. |
account/, tor/, network/, service/, ui/media/ |
Account storage, Tor, HTTP, scheduled posts, video/audio players. |
A new shared feature that needs a desktop behaviour = a member on one of the ports above (default in the interface, override here), not a desktop branch in the shared screen.
Shortcuts and menu bar
- One
Commandenum inDesktopMenuBar.ktdrives both.Command.shortcutis Cmd+key on macOS, Ctrl+key elsewhere (isMac = PlatformInfo.host == Platform.MACOS). - macOS: the system
MenuBarcarries the shortcuts. Linux/Windows get no menu bar (Swing draws it inside the window); shortcuts go throughhandleShortcutfrom the window'sonPreviewKeyEvent. - Deck commands are ignored unless
DeckCommandBus.active; held chords are de-duplicated (AUTO_REPEAT_WINDOW_MS). - Menu labels are
Res.string.*(commonsUI strings, per AGENTS.md "Strings").
OS detection
PlatformInfo.current honours an override (-Damethyst.platform=GNOME or AMETHYST_PLATFORM) to
preview another OS's theming; PlatformInfo.host is the real OS — use it for anything that touches
the actual system (menu bar, Cmd key, shell-outs).
Keys
Keys go to the OS keyring through SecureKeyStorage
(commons/src/jvmMain/.../commons/keystorage/SecureKeyStorage.kt, java-keyring). Without one they
go to a NIP-49 password file (PasswordKeyFile), and a login can opt out of keeping its key. The
status, prompts and Settings › Key storage are shared (KeyStorageController, provided by
DesktopAppRoot.keyStorage); see commons/plans/2026-10-12-desktop-key-storage.md.
The keyring breaks in release builds only, so test the packaged app: Amethyst --keyring-self-test
(CI runs it through keyring-self-test.sh in the repo's top-level scripts folder). ProGuard must keep jkeychain's native library and
dbus-java's ServiceLoader transport, and drop the signatures of jars it rewrites (hkdf):
desktopApp/compose-rules.pro, verifyJkeychainNativeSurvivesProguard,
verifyDbusTransportSurvivesProguard.
Run and package
./gradlew :desktopApp:run # JDK 21 toolchain (jvmToolchain(21))
./gradlew :desktopApp:run -Damethyst.dataDir=/tmp/amy-test # separate profile; -Damethyst.debug=true for DEBUG logs
./gradlew :desktopApp:packageDmg # macOS; packageMsi (Windows), packageDeb / packageRpm (Linux)
mainClass = "com.vitorpamplona.amethyst.desktop.app.AmethystDesktopKt". Data lives in~/.amethyst/appunlessamethyst.dataDiris set.- Packages land in
desktopApp/build/compose/binaries/main/(release variants inmain-release/). - Stop a running app before rebuilding shared modules. A build rewrites the jars the running
:desktopApp:runJVM loaded and it crashes withNoClassDefFoundError. Relaunch it afterwards. - Build fails? Check
java -version(21+), then that./gradlew :quartz:buildcompiles.
Verify a UI change by running it (headless too)
The window renders the shared UI, so this is how an agent checks a commonsUI/commons change for
real (AGENTS.md "Run the app before calling a UI change done"). tools/desktop-run/ does it without
a display or a window manager: run-headless.sh start runs Xvfb + :desktopApp:run on a scratch
profile (/tmp/amethyst-desktop-run/profile), waits for the first paint and saves shot.png;
Drive.java (pure JDK java.awt.Robot) clicks, types, presses keys, scrolls and takes screenshots.
Read the screenshots with the image-reading tool. Details: tools/desktop-run/README.md.
- Log in with a public
npubfor a read-only session. A throwaway Sign Up account is only for flows that must sign, and only when asked, because it publishes to real relays. - The screen size picks the shell:
AMETHYST_SCREEN=480x900x24gives the phone layout (bottom bar), the default 1600x1000 gives the permanent drawer + docked notifications. Use a newAMETHYST_DISPLAYper size. - Linux packages bundle the JetBrains Runtime (build on
jbrsdk21, see BUILDING.md "Wayland and X11 on Linux");scripts/wayland-smoke-test.sh <launcher>checks one on a sway with no Xwayland. - Under Xvfb: no GL (the script sets
SKIKO_RENDER_API=SOFTWARE), no keyring (password-file fallback), no native video player ("Can't play this video"). Those are the environment, not your change.run-headless.sh logslists exceptions first. - Never
pkill -f AmethystDesktopKtfrom a tool shell: it matches the shell itself. Usestop.
For a check that must keep passing, write a Compose UI test (createComposeRule(), see
desktopApp/src/jvmTest/.../desktop/ui/BlockInteractionsUiTest.kt); CI runs them under
xvfb-run --auto-servernum ./gradlew :desktopApp:test.
Tests: ./gradlew :desktopApp:test (a plain JVM module: sources sit in src/jvmTest but the task
is test); desktopApp/src/jvmTest/.../desktop/testrelay/ has an in-process relay fixture
(LaunchFixtureRelay).