#gpui.mbt

#What you can use today

• Application state — App, typed Entity[T], scoped updates, subscriptions, explicit notifications, deterministic queued work, and manually advanced timers.
• Layout and interaction — deterministic row/column flex layout, recursive layout trees, hit testing, capture/bubble pointer dispatch, stop-propagation, focus state, and portable scroll state and drag gestures.
• Scene data — ordered quads and bounded plain-text items, rectangle clip chains, affine transforms, opacity, and canonical SceneSnapshot data. The browser uses its system font; experimental Ubuntu, Windows, and macOS renderers draw documented grayscale subsets. macOS uses CoreText system sans for bounded single-line text; this does not add an editor or IME.
• Linux text — merged PR #27 provides copied PangoFT2 measurement, caret, and hit-test geometry; Ubuntu's GLES host now also presents supported plain-text items through grayscale masks. This is not text input, an editor, or a general Linux support claim; see the Linux text guide.
• Semantic capabilities — one typed operation can be bound to GUI actions, direct MoonBit calls, and optional MCP dispatch with shared domain validation. A checked JavaScript stdio fixture exercises the pinned stateless MCP wire adapter.
• macOS — an AppKit + Metal native host with windows, input, clipboard/cursors, scale/resize events, quad and bounded single-line grayscale text presentation, CoreText measurement, and an experimental renderer-recovery path.
• Ubuntu / Wayland — a Wayland + EGL/OpenGL ES 2 native host with window lifecycle, input, clipboard/cursor services, scale handling, quad presentation, and bounded grayscale text frames.
• Windows — an experimental one-window Win32/D3D11 hardware-or-WARP slice with basic input, quad presentation, bounded grayscale text, and a focused single-line text field. The private IMM32 text-session ingress is opt-in and default-off; real Japanese IME qualification remains open. Prior hosted Windows runs cover earlier slices and do not establish a Windows support tier or production claim; see the Windows native guide.
• Browser — Weekboard, a small website-launch task board using the shared MoonBit app/layout/event/scene model and a Canvas 2D host, plus the retained interaction lab for service and lifecycle proofs.
• Headless testing — portable model, layout, event, focus, and scene behavior can be exercised without a window system.

#Try it

#Headless MoonBit model

moon test examples/headless

#macOS

./script/build_and_run.sh

#Ubuntu / Wayland

sh scripts/prepare_ubuntu.sh
moon run examples/ubuntu --target native

#Headless Linux text geometry

sh scripts/test_linux_text.sh

#Browser

vp install --frozen-lockfile
vp dev

#MCP stdio adapter

sh scripts/run_mcp_stdio.sh
sh scripts/test_mcp_stdio.sh

#MoonBit programming model

pub fn increment(
  app : @core.App,
  entity : @core.Entity[Int],
) -> Result[Unit, @diagnostics.FrameworkError] {
  app.update(entity, context => {
    match context.get() {
      Err(error) => Err(error)
      Ok(value) =>
        match context.set(value + 1) {
          Err(error) => Err(error)
          Ok(_) => context.notify()
        }
    }
  })
}

#Packages

#Documentation

• Status, current limits, and roadmap
• Product model
• Architecture and dependency boundaries
• Portable text value model
• Linux text measurement and Ubuntu grayscale drawing
• GPUI compatibility matrix
• macOS native host
• Ubuntu / Wayland host
• Reproducible Debian cloud desktop
• Browser demos and interaction lab
• MCP adapter and stdio fixture
• Testing strategy and gates
• Open implementation packets

#Relationship to GPUI