wgpu-scry

System-webview frame adapter for wgpu hosts. The scrying library embeds the platform webview (WebView2, WKWebView, WebKitGTK, WPE), produces frames the host renderer can consume as GPU textures or CPU snapshots, and forwards navigation, input, and browser-surface APIs back to the page.

Extracted from wgpu-graft on 2026-05-05.

Status (2026-10-05 source audit)

scrying 0.7.1 is the published callback-order release. The retained registry-only triplet receipt covers WebView2/DX12, WKWebView/Metal on M4 and Intel, and WPE/Vulkan on RADV; it does not establish identical browser capabilities across all five backends. See wgpu-graft/design_docs/2026-09-03_wgpu_triplet_release_plan.md. Native frame resources have move-only, RAII custody, and the primary WebView2, WKWebView, and WPE producers expose correlated asynchronous script results through one ordered event queue. It carries feature-selected wgpu 28/29/30, defaults to wgpu 30, and requires at least wgpu 30.0.1 on that row.

• Frame transports are proven per platform: Windows WebView2 capture into a shared D3D11 texture imported by wgpu D3D12 (the reference implementation); macOS WKWebView via ScreenCaptureKit and IOSurface into Metal (macOS 14+); Linux WebKitGTK 4.1 and 6.0 via CPU snapshot; Linux WPE via DMABUF into Vulkan.
• Beyond frames, the WebSurfaceProducer trait covers navigation, history, input, ordered events, correlated script results, and cookies. Concrete producers additionally expose backend-specific custom schemes, downloads, profiles, popups, find, and PDF APIs. These are not all methods on the portable trait or reachable through downstream adapters. Per-backend caveats live in docs/parity-matrix.md.
• DX12, Metal, and Vulkan/DMABUF imports delegate to published grafting 0.6.0; Scry keeps webview and sync policy.
• CI runs the macOS suite, the WebKitGTK 4.1 Linux suite, and a required Fedora 44 WPE producer/demo build on every push.

main includes September 11 macOS capture-status diagnostics beyond the published September 4 receipt. Its manifest still reads 0.7.1; that source reconciliation was not published. The October 4 headed run on that exact source passed M4 and Windows; Intel failed the base capture cadence assertion, and RADV failed its session preflight before WPE tests ran. Native diagnostic output now exists, but the counter unit test and complete affected-platform acceptance remain open. See the diagnostics record and next-release gates.

Open items are a native GTK4 input path for webkit6 (current input is JS-synthesized), crash recovery for webkit6/WPE, broader IME parity, and webkit6 zero-copy import. WPE Vulkan DCC sampling is now a hard green gate on AMD Renoir/RADV; the headed hardware command and receipt are documented in docs/wpe-deployment.md.

Use

For wgpu hosts that want a system webview rendered inside their own pipeline:

[dependencies]
scrying = "0.7"

# Hosts on an adjacent wgpu major select it explicitly.
scrying = { version = "0.7", default-features = false, features = ["wgpu-29"] }

The default wgpu row is 30. wgpu-28, wgpu-29, and wgpu-30 are carried; disable default features when selecting 28 or 29. On Linux, combine that row with one of webkitgtk-fallback, webkit6, or wpe. Omitting all three keeps the WPE producer type available as a compile-only shell; wpe enables its WPEPlatform FFI and live DMABUF production.

Each backend has a runnable demo probe with flagged assertion modes. The cross-platform probe intentionally pins wgpu 30 and selects scrying's wgpu-30 feature, so it is a compiled host-side type-identity receipt rather than merely another library check:

cargo run -p demo-scrying-winit   # cross-platform backend-selection smoke
cargo run -p demo-win             # Windows; ~18 --*-test assertion flags
cargo run -p demo-mac             # macOS; bash scripts/test-mac.sh runs the suite
cargo run -p demo-linux           # WebKitGTK 4.1; bash scripts/test-linux.sh
cargo run -p demo-linux6          # WebKitGTK 6.0
cargo run -p demo-wpe             # WPE (see docs/wpe-deployment.md)

Deeper documentation: scrying/README.md (producer contract and GPU sync), docs/parity-matrix.md, and docs/wpe-deployment.md.

Siblings

The family splits engine embedding by target: wgpu-graft (Servo, plus the shared grafting interop core), wgpu-scry (system webviews), and wgpu-weld (CEF/Chromium).

License

MPL-2.0. The scrying::native_frame module is structurally derived from Slint's MIT-licensed Servo embedding example; see NOTICE.