kymostudio-core (Rust)

Pure-Rust SVG → PNG rasterizer core for kymostudio, built on resvg. No browser, no headless Chrome, no C/Cairo/Skia system dependencies.

One core crate, compiled to four targets from a single source via feature flags — so the Rust CLI, the Python package, and the JS/browser playground all share the exact same resvg engine (resvg is CSS-class-aware, the reason the project avoids cairosvg):

svg_to_png(svg: &[u8], scale: f32) -> Result<Vec<u8>, RenderError> is the one core function; each binding (src/python.rs, src/wasm.rs) is a thin façade.

CLI — kymo

kymo -i in.svg out.png          # rasterize at intrinsic size
kymo -i diagram.svg             # output defaults to diagram.png
kymo -i diagram.svg -s 2 hi.png # 2× resolution

Build each target

# Native (CLI + lib + tests)
cargo test
cargo build --release --bin kymo          # -> target/release/kymo

# Python wheel (abi3, one wheel for CPython ≥ 3.10)
maturin build --release --out dist        # -> dist/kymostudio_core-*-abi3-*.whl
#   import _kymostudio_core; _kymostudio_core.svg_to_png(svg_bytes, scale)

# wasm (browser + Node) — system-fonts OFF (no fs/mmap on wasm)
wasm-pack build --target web --out-dir pkg --out-name kymostudio_core \
  -- --no-default-features --features wasm
#   import { svgToPng } from './pkg/kymostudio_core.js'

CI builds and smoke-tests all of the above across Linux/macOS/Windows — see .github/workflows/rust.yml.

Library use (Rust)

let svg = std::fs::read("in.svg")?;
let png: Vec<u8> = kymostudio_core::svg_to_png(&svg, 1.0)?;
std::fs::write("out.png", png)?;

The version is kept in lockstep with the rest of the monorepo (Cargo.toml → version).