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Img2Num JS/WASM Bindings

The Img2Num JS/WASM Bindings allow the core Img2Num image processing library to be used in JavaScript environments via WebAssembly. These bindings expose high-performance image processing, clustering, filtering, and SVG conversion functions to web and Node.js projects.

Overview​

The bindings wrap the C++ functions in a WASM module using Emscripten. Key image processing operations are exposed as EMSCRIPTEN_KEEPALIVE functions and operate on Uint8Array buffers in JavaScript.

Key Functions​

  • gaussian_blur_fft — Apply FFT-based Gaussian blur
  • invert_image — Invert pixel values in an image
  • threshold_image — Apply thresholding to an image
  • black_threshold_image — Apply black-thresholding
  • kmeans — Perform k-means clustering on image pixels
  • bilateral_filter — Apply bilateral filtering
  • labels_to_svg — Convert labeled image to SVG

Each function is documented with Doxygen and mirrors the functionality of the corresponding C++ function.

Building the WASM Module​

Run this in the root of the project
emcmake cmake -B build-wasm .
cmake --build build-wasm
  • The module outputs index.js and index.wasm in packages/js/build-wasm.
  • Core library object files (core_obj) must be available and linked.
  • SIMD support (-msimd128) is enabled for performance.
Using JavaScript

Interfacing with raw WASM in JavaScript is dangerous. As a result, we have built a safety wrapper around it to avoid manual memory management.

See packages/js.

Documentation​

Detailed Doxygen documentation is available for each function, describing parameters, expected input types, and usage examples. Refer to the generated docs for guidance on integrating the WASM bindings into internal projects.