GPUI

A standalone extraction of Zed's GPU-accelerated UI framework.

GPUI is a hybrid immediate and retained mode, GPU accelerated, UI framework for Rust.

Getting Started

Add GPUI as a git dependency:

[dependencies]
gpui = { package = "bumpyclock-gpui", git = "https://github.com/BumpyClock/gpui", rev = "<full-40-character-commit-sha>" }

Replace the placeholder with an immutable commit containing the renamed bumpyclock-gpui package; do not depend on main.

See crates/gpui/examples/ for example applications.

Building

cargo check -p bumpyclock-gpui
cargo test -p bumpyclock-gpui --features test-support
cargo build --example hello_world

Application lifecycle

GPUI library code performs orderly shutdown and returns control to its host; it does not terminate the process. Executables remain responsible for choosing an exit code or restart policy after Application::run returns.

Host	Application::run ownership and return
Native and headless	Blocks in the platform loop, gives on_app_quit futures up to 100 ms, then returns normally. Native platform loops are one-shot.
Web	Returns after scheduling asynchronous launch. GPUI retains the application on the browser thread until shutdown; quit observers and the 100 ms timeout finish asynchronously because the browser event loop cannot be blocked.
Embedded	run_embedded returns an ApplicationHandle; the embedder owns that handle and drives the host run loop. Dropping it before an asynchronously scheduled launch cancels that launch.

A quit requested during launch or later through App::quit wakes a blocking native/headless loop. Cross-thread callers should submit the request through MainThreadPoster. The first quit closes poster admission, drops queued/deferred effects, invokes the platform quit callback and shutdown observers once, and starts the observer window. Repeated quit requests are no-ops, and posters obtained before or after shutdown reject new submissions.

QuitMode controls window-driven shutdown:

• Explicit remains alive with zero windows until App::quit or an implemented OS quit request.
• LastWindowClosed quits after the final window closes.
• Default is Explicit on macOS and LastWindowClosed elsewhere.
• On macOS, an AppKit termination request enters the same orderly quit path and cancels immediate process termination while GPUI stops and wakes its owned run loop. Windows session-end messages (WM_QUERYENDSESSION / WM_ENDSESSION) remain unsupported and do not enter GPUI's orderly shutdown path.

Headless Web construction is unsupported and is reported by the fallible gpui_platform::try_headless and try_current_platform APIs. The legacy infallible constructor wrappers remain for compatibility and panic when platform initialization fails.

Renderer and native evidence

RendererSelection::{Default, Software} controls adapter policy through GPUI_RENDERER=default|software. Software mode is strict: Windows selects D3D11 WARP; WGPU-backed Linux selects only a Vulkan CPU/software adapter; macOS returns an error because Metal has no software adapter. An exact lavapipe claim also requires a constrained Vulkan ICD and matching adapter-name evidence.

Window::renderer_info() reports structured selection, renderer, backend, adapter name, and adapter type. PresentationEvidence::ApiSubmitted means only that a presentation API call returned; WGPU uses it after SurfaceTexture::present(). PresentationEvidence::BackendAccepted means a backend accepted or scheduled work; DXGI Present and backend-specific Metal status still do not prove scanout. Software-GPU evidence is not hardware-GPU evidence.

Native conformance consumers should pair HasWindowHandle with HasDisplayHandle and serialize only pointer-free handle kinds. Matching window/display families prove native construction, not presentation. A real presentation claim requires separate renderer and first-presentation evidence.

Upstream Sync

GPUI is a selective semantic fork of Zed, not a contiguous merge. Exact provenance and maintained divergence clusters live in fork.toml, the machine-readable source of truth. See UPSTREAM.md for sync policy, invariants, exclusions, verification evidence, and the next-sync procedure.

Platform validation

The repository currently proves source builds and backend-focused tests. Native runtime behavior remains session- and hardware-dependent: backend tests are not full application/window conformance, Linux compile tests are not live X11 or Wayland compositor runs, and WebAssembly is compile-only. Downstream Stage 1 native jobs may add stronger retained evidence, but configured jobs are not passed runs. See CI and UPSTREAM.md before treating a platform as production-supported.

Target	CI evidence	Maturity
macOS	Native backend tests on macOS runner; no full app/window presentation claim	preview
Windows	Native backend tests plus shader compile on Windows runner; no full app/window presentation claim	preview
Linux X11	Backend compile and tests; no live X11 display/presentation	experimental
Linux Wayland	Backend compile and tests; no live Wayland compositor/presentation	experimental
WebAssembly	Nightly compile-only checks	compile-only

License

The extracted GPUI crates generally declare Apache-2.0; zlog, ztracing, and ztracing_macro declare GPL-3.0-or-later. See crate manifests and LICENSE-AUDIT.md for the unresolved combined-publication review.