Native Platform Matrix

Native Platform Matrix

Feature support per backend and operating system. ✓ = functional, ✗ = stub/unavailable.

Consolidated Feature Matrix

Feature	macOS (Metal)	Linux (GL)	Windows (GL)	Web (WASM)	Android	iOS
Open file	✓	✓	✓	✓	✗	✗
Save file	✓	✓	✓	✓¹	✗	✗
Folder dialog	✓	✓	✓	✓²	✗	✗
Message dialog	✓	✓	✓	✓	✗	✗
Confirm dialog	✓	✓	✓	✓	✗	✗
Save/discard	✓	✓	✓	✗	✗	✗
Print dialog	✓	✓⁴	✓⁵	✓⁶	✗	✗
Notifications	✓⁷	✓⁸	✓⁹	✓¹⁰	✓	✗
A11y tree sync	✓¹¹	✓¹²	✗	✓¹³	✓	✗
IME input	✓	✓	✓	✓	✓	✗
Native menubar	✓¹⁴	✗	✗	✗	✗	✗
System tray	✓¹⁵	✓¹⁶	✓¹⁶	✗	✗	✗
Spell check	✓¹⁷	✓¹⁸	✗	✗	✗	✗
Open URI	✓	✓	✓	✓	✓	✗¹⁹
Dark titlebar	✗	✗	✗	✗	✗	✗
Bookmarks	✗	✗	✗	✗	✗	✗

¹ Web save uses File System Access API (showSaveFilePicker); falls back to suggested filename.
² Web folder uses showDirectoryPicker.
⁴ Linux: PDF rendered to temp file, opened via lpr or xdg-open.
⁵ Windows: PDF rendered to temp file, opened via ShellExecuteW "print".
⁶ Web: renders canvas to PNG in hidden iframe, calls window.print().
⁷ macOS: osascript display notification.
⁸ Linux: notify-send via D-Bus.
⁹ Windows: PowerShell System.Windows.Forms.NotifyIcon balloon tip.
¹⁰ Web: Notification API with permission request.
¹¹ macOS: NSAccessibility protocol via C bridge (VoiceOver).
¹² Linux: AT-SPI D-Bus via atspi bridge.
¹³ Web: DOM ARIA attributes on canvas-adjacent elements. Windows lacks both UIA and AT-SPI bridges.
¹⁴ macOS: NSMenu/NSMenuItem via C bridge. Native menubar is an AppKit-only concept.
¹⁵ macOS: NSStatusBar via C bridge.
¹⁶ Linux: StatusNotifierItem D-Bus (sni package). Windows: Shell_NotifyIconW (sni package).
¹⁷ macOS: NSSpellChecker via C bridge.
¹⁸ Linux requires hunspell build tag and libhunspell-dev at build time.
¹⁹ iOS validates URI scheme but returns "not implemented".

Dialogs

Feature	macOS (Metal)	Linux (GL)	Windows (GL)	Web (WASM)	Android	iOS
Open file	✓	✓	✓	✓	✗	✗
Save file	✓	✓	✓	✓¹	✗	✗
Open folder	✓	✓	✓	✓²	✗	✗
Message (alert)	✓	✓	✓	✓	✗	✗
Confirm (OK/Cancel)	✓	✓	✓	✓	✗	✗
Save/Discard/Cancel	✓	✓	✓	✗	✗	✗

¹ Web save uses File System Access API (showSaveFilePicker); falls back to suggested filename.
² Web folder uses showDirectoryPicker.

Printing

Feature	macOS (Metal)	Linux (GL)	Windows (GL)	Web (WASM)	Android	iOS
Print dialog	✓	✓¹	✓²	✓³	✗	✗

¹ Linux: PDF rendered to temp file, opened via lpr or xdg-open.
² Windows: PDF rendered to temp file, opened via ShellExecuteW "print".
³ Web: renders canvas to PNG in hidden iframe, calls window.print().

Notifications

Feature	macOS (Metal)	Linux (GL)	Windows (GL)	Web (WASM)	Android	iOS
OS notification	✓¹	✓²	✓³	✓⁴	✓	✗

¹ macOS: osascript display notification.
² Linux: notify-send via D-Bus.
³ Windows: PowerShell System.Windows.Forms.NotifyIcon balloon tip.
⁴ Web: Notification API with permission request.

Accessibility

Feature	macOS (Metal)	Linux (GL)	Windows (GL)	Web (WASM)	Android	iOS
Init/Sync	✓¹	✓²	✗	✓³	✓	✗
Announce	✓	✓	✗	✓	✓	✗
Full tree sync	✓	✓	✗	✓	✓	✗

¹ macOS: NSAccessibility protocol via C bridge (VoiceOver).
² Linux: AT-SPI D-Bus via atspi bridge.
³ Web: DOM ARIA attributes on canvas-adjacent elements.
Windows lacks both UIA and AT-SPI bridges — a11y is not functional there.

IME / Text Input

Feature	macOS (Metal)	Linux (GL)	Windows (GL)	Web (WASM)	Android	iOS
Start/Stop	✓	✓	✓	✓	✓	✗
Cursor rect	✓	✓	✓	✓	✓	✗

macOS: native IME via AppKit. Linux/Windows: native IME via platform input APIs. Android: native Kotlin bridge. Web: hidden <input> element.

Native Menubar

Feature	macOS (Metal)	Linux (GL)	Windows (GL)	Web (WASM)	Android	iOS
Set/Clear menubar	✓¹	✗	✗	✗	✗	✗

¹ macOS: NSMenu/NSMenuItem via C bridge. Native menubar is an AppKit-only concept.

System Tray

Feature	macOS (Metal)	Linux (GL)	Windows (GL)	Web (WASM)	Android	iOS
Create/Update/Remove	✓¹	✓²	✓²	✗	✗	✗

¹ macOS: NSStatusBar via C bridge.
² Linux: StatusNotifierItem D-Bus (sni package). Windows: Shell_NotifyIconW (sni package).

Spell Check

Feature	macOS (Metal)	Linux (GL)¹	Windows (GL)	Web (WASM)	Android	iOS
Check/Suggest	✓	✓	✗	✗²	✗	✗
Learn word	✓	✓	✗	✗	✗	✗

¹ Linux requires hunspell build tag and libhunspell-dev at build time. Without the tag, falls to spellcheck_other.go stub.
² Web: "no browser JS API exposes spell results" — upstream limitation.

Security-Scoped Bookmarks

Feature	All platforms
Load/Persist/Stop	✗

Bookmark support (macOS security-scoped URLs for sandboxed file access) is unimplemented on all backends. The macOS C dialog layer parses bookmarkData from NSOpenPanel, but the Go side does not consume it.

Titlebar Dark

Feature	All platforms
Dark titlebar	✗

No-op on all backends. Requires platform-specific window manager calls (macOS NSWindow.appearance, Windows DwmSetWindowAttribute, Linux GTK_CSD).

URI Opening

Feature	macOS (Metal)	Linux (GL)	Windows (GL)	Web (WASM)	Android	iOS
OpenURI	✓¹	✓²	✓²	✓³	✓	✗⁴

¹ macOS: open command with scheme validation (http, https, mailto).
² Linux: xdg-open. Windows: rundll32 url.dll,FileProtocolHandler.
³ Web: window.open(uri, '_blank').
⁴ iOS validates URI scheme but returns "not implemented".

Backend Selection Summary

OS	Default Backend	Alt Backend	Build Tag
macOS	Metal	—	darwin && !ios
Linux	GL	—	linux && !js && !android && !gl
Windows	GL	—	windows && !js && !android && !gl
Web	Web (WASM)	—	js && wasm
Android	Android	—	android
iOS	iOS	—	ios

The GL backend can be forced on non-Apple desktop platforms with -tags gl (build tag !darwin && !js && !android && gl). macOS always uses Metal — run_darwin.go matches darwin && !ios unconditionally.