longbridge / gpui-fast

# GPUI Fast
A performance-focused fork of Zed's GPUI with incremental rendering and native window composition. v0.1.0 is available on crates.io. The project remains experimental.
- **Retained Mode** reuses unchanged views, layout nodes and text measurements.
- **Scroll layers** reuse cached GPU tiles and list rows while scrolling, on macOS, Linux and Windows.
- **Window composition** embeds native content while keeping GPUI menus, popovers and dialogs above it.
## Retained Mode
GPUI Fast tracks rendering dependencies and rebuilds only what changed. Recorded Linux release-build CPU time per frame:
| Workload | Baseline | GPUI Fast |
| --- | --- | --- |
| Unchanged window | 3.31 ms | 0.19 ms (−94%) |
| Sidebar scrolling | 5.95 ms | 0.79 ms (−87%) |
| Streaming quotes | 5.06 ms | 1.35 ms (−73%) |
The unchanged-window baseline disables retention in the same build; the other rows compare against upstream `gpui-pre` 0.3.7. Results depend on the workload. See Retained Mode and Scroll layers for measurements and implementation details.
## Window composition
Opt-in composition supports macOS, Windows and Linux (Wayland and X11), based on zed#62379. GPUI menus, popovers and dialogs, including their shadows and translucent backdrops, render above the native content on all three:
| Platform | Native content | GPUI overlays |
| --- | --- | --- |
| macOS | AppKit view (WKWebView) | Overlay layer |
| Windows | WebView2 composition | Overlay layer |
| Linux (Wayland) | Subsurface | Overlay subsurfaces |
| Linux (X11) | Child window (WebKitGTK) | Overlay window blended by the compositing manager; cut out of the native content without one |
 [code] 
## Using it
Alias the published crates to GPUI's library names:
 [code] 
The platform features above select Linux backends; omit them on macOS and Windows. GPUI Kit applications should follow the compatibility setup to use the same GPUI core.
Changes to render state outside tracked entities, globals and list/scroll state need `cx.notify()`. See Retained Mode for details.
## Following upstream
v0.1.0 includes Zed's GPUI through `a1b71072e5`. UPSTREAM records the revision for the current checkout.
GPUI Fast keeps its implementation in `fast/` modules with small hooks into upstream code, making future syncs easier. See Architecture and Contributing for design, building and testing.
## License
Apache-2.0 — copyright Zed Industries, Inc. This is a modified fork; see LICENSE-APACHE.