f171c147f5
Selecting text in a Japanese or Chinese layout now shows a menu above the selection: Ruby, Emphasis, and for Japanese, Warichu and Combine. Ruby opens an input to add, change or remove the reading; Emphasis opens a list of marks with icons; Warichu and Combine toggle on the selection. The renderer exports the selection bounds so the menu can centre on them, and new icons draw each emphasis mark. A reading had to cover a single span, so putting emphasis on part of a word blocked furigana on it. A reading can now cover adjacent spans of different styles: - Applying a reading gives the selected spans one new ruby-group id. Splitting a span keeps the id. Spans without one, as in every existing file, keep one base per span; matching readings alone never join, so per-character readings such as 天天 stay apart. - The span binary marks a span that joins the previous base with bit 2 of the ruby flags byte, so the format keeps its size. - Paragraph::ruby_groups defines a base for the renderer. Horizontal placement, long-reading spacing, paint, bounds, justification, overflow and line breaks use it, as do the vertical base units, ruby layout and column breaks. - The editor accepts a reading over any selection without readings or warichu, or over a whole base. Warichu still needs one span. - HTML and foreignObject draw one ruby per base, CSS code generation writes one set of rules per base, and SVG export draws one reading per line of a base through the new ruby-x and ruby-width keys. AI-assisted-by: claude-opus-5-5
Penpot WASM render
This is the canvas-based WebAssembly render engine for Penpot.
Rust & Emscripten
This project is a Rust crate that targets Emscripten (wasm32-unknown-emscripten).
We use wasm32-unknown-emscripten compilation target:
- It compiles Rust code into WASM
- It generates the JavaScript code (“glue”) to load and run the WASM code
Skia
We use Skia, an Open Source 2D graphics library. In particular, the render engine uses Skia via custom binaries of the rust-skia crate.
How to build
With the Penpot Development Environment running, create a new tab in the tmux.
cd penpot/render-wasm
./build
You can also use ./watch to run the build on every change.
The build script compiles the project and copies the .js and .wasm files to the app that uses each target.
Render targets
The same Rust source produces two artifacts, which differ only in compiler options:
| Target | Tuned for | Cargo profile | Consumed by |
|---|---|---|---|
frontend |
speed | release (-O3) |
frontend/resources/public/js |
export |
size | size (-Oz) |
exporter/resources/wasm |
./build # both targets, frontend first
./build frontend # workspace / viewer renderer
./build export # headless exporter renderer
./watch still follows a single target (frontend unless you pass one),
since watching both would rebuild twice on every keystroke.
Each target keeps its own CARGO_TARGET_DIR (target/<target>), so switching
between them does not invalidate the other's cache. Set BUILD_MODE=release
(or NODE_ENV=production) for an optimized build; the default is debug.
Set PENPOT_WASM_PREPARED=1 when the pinned Rust toolchain is selected, its
Emscripten target is installed, and this package's Node dependencies are
installed. ./build, ./test, ./lint and ./fmt then skip rustup setup
and pnpm install. Benchmark preparation sets this flag for each retained
build.
Serialize builds in one checkout
All targets in one checkout share one flock lock stored at
render-wasm/.render-wasm-build.lock. The lock covers dependency setup, the
Cargo build, artifact copy, and target cleanup. If another build or cleanup
already holds the lock, the new process prints a waiting message and starts
only after the first process exits.
The watch command takes the lock for each build, then releases it while it waits for source changes. The lock file stays in the checkout after a build, but the operating system releases its lock when the process exits, including after an error or signal.
The lock applies to one checkout and only to commands that use these scripts.
A manual Cargo build can still write to the same target without taking the
lock. Set RENDER_WASM_LOCK_FILE to the same path in each process when you
make different checkouts share a CARGO_TARGET_DIR. The supported Linux build
environment must provide flock from util-linux; flock --version checks this
dependency.
Use the target cleanup commands instead of running cargo clean on the shared
target/ directory:
./clean frontend # remove target/frontend only
./clean export # remove target/export only
Each target writes its own generated shared.js (the enum discriminants the
CLJS side compiles against) next to the code that imports it — respectively
frontend/src/app/render_wasm/api/shared.js and
exporter/src/app/wasm/shared.js. Neither build writes to the other's paths.
Edit your local frontend/resources/public/js/config.js to add the following flags:
enable-feature-render-wasmto enable this render engine.enable-render-wasm-dpr(optional), to enable using the device pixel ratio.
How to test
We currently have two types of tests:
- Unit tests
cd penpot/render-wasm
./test