BinaryFrontend gains a Threshold enum: Fixed(u8) (now tunable, was
hardcoded to 128) and Adaptive { window, t } — Bradley–Roth adaptive
thresholding computed via visioncortex's SummedAreaTable, O(pixels)
regardless of window size, for images with uneven lighting. Both use a
shared (r+g+b)/3 intensity so they agree on "dark"; the grayscale
checker_bw golden is unaffected.
Exposed through Config and all bindings: CLI (--threshold, --adaptive,
--adaptive-window, --adaptive-t), Python (constructor kwargs + getters/
setters), and the Node package (binaryThreshold, adaptive, adaptiveWindow,
adaptiveT). Adds tests covering fixed tunability and adaptive recovering
locally-dark marks under a brightness gradient that a global cutoff can't.
New nodejs/ package: a wasm-bindgen crate (vtracer-wasm) built with wasm-pack
that wraps the vtracer framework, plus a thin JS layer for file I/O. Image
decoding (png/jpeg/gif/bmp via the image crate) runs in wasm too, so the
package has zero native dependencies — no sharp, no node-gyp.
No separate general-purpose wasm crate: the Node package directly owns and
wraps the wasm. Excluded from the cargo workspace (wasm-bindgen cdylib), built
with wasm-pack.
JS API (camelCase options): convertBuffer, convertPixels, convertFile,
convertFileSync — each taking an Options object (preset, colorMode,
hierarchical/cutout mosaic, mode, palette, maxColors, optimize, ...). Ships
index.d.ts types and a node smoke test. README updated.
Verified: builds to wasm32-unknown-unknown; `node test.js` passes; output
matches the CLI/Python bindings (253 paths on the tank sample).
Chris Tsang