wimagemagick

A feature-complete ImageMagick build with all modern dependencies, compiled for WASM so it can be easily run in a modern browser.

Install

npm install @wasmedia/wimagemagick

import { initWImageMagick } from '@wasmedia/wimagemagick';

const wim = await initWImageMagick();
const img = wim.Image.fromBuffer(bytes);
const jpeg = img.fit(1600, 1600).quality(85).toBuffer('JPEG');
img.dispose();

The package ships the .wasm (about 15 MB, 5 MB gzipped) next to its JS, and loads it relative to the module, so a bundler that copies assets referenced by new URL(..., import.meta.url) needs no configuration. docs/api.md has the full API, including the Web Worker entry (@wasmedia/wimagemagick/worker). The WASM statically links ImageMagick and several LGPL libraries; their licences are in dist/licenses/.

Try it without installing at magick.wasmedia.org.

File mode

executeFiles() runs a command over files instead of buffers: OPFS file handles in a Web Worker, host paths under Node. The files are mounted through wopfs rather than copied into memory, which halves peak memory on a large image (640 → 315 MiB on a 24-megapixel TIFF):

const r = await wim.executeFiles('shot.cr2 -resize 50% shot.jpg',
  [{ name: 'shot.cr2', file: fileHandle }], { outputDir: dirHandle });

See File mode. wopfs (MIT) is loaded only when file mode is first used.

Format & Feature Scope

• Excluded: Ghostscript-based features (PDF rendering), FFmpeg-based features (video)
• Included: As many image formats as practical, specifically:
  • Common raster, read and write: JPEG, PNG, WebP, TIFF, GIF, BMP, AVIF, JXL, JP2/J2K
  • HEIC/HEIF (via libheif) — decode only; encoding would need x265
  • RAW camera formats (via LibRaw) — decode only; the common ones are detected from their headers, see Reading RAW files
  • Other formats as practical to cross-compile

docs/building.md has the verified format matrix and the list of delegates that are deliberately absent.

Technical Requirements

• ImageMagick version: Always target the current stable release (currently v7)
• API surface: Both CLI-style interface (pass command strings) and C API (MagickWand/MagickCore)
• JS wrapper: High-level JS wrapper on top of the C bindings, plus CLI-style command execution
• Toolchain: Open to any practical WASM toolchain (Emscripten is the likely choice)
• Output: Both a single .wasm + JS glue bundle and an npm-distributable package
• Bundle size: Large binaries are acceptable if necessary to support the full format set
• File I/O: Support both Emscripten virtual filesystem (MEMFS) and direct ArrayBuffer/Blob passing
• Web Workers: Should support running off the main thread
• Distribution: Open source, published to npm as @wasmedia/wimagemagick
• Browser support: Chrome and Safari at minimum
• Build: Single-threaded + SIMD — works on any site without special headers

Prior Art

| Project | Status | IM Version | Delegates | Threading/SIMD | API Style | |---------|--------|------------|-----------|----------------|-----------| | @imagemagick/magick-wasm | Active, ~853 stars | v7 (current) | Rich (HEIF, WebP, RAW, JXL, EXR) | None | OOP TypeScript only | | WASM-ImageMagick | Abandoned (2023) | v7 (~2019 era) | Minimal (JPEG, PNG, TIFF, GIF) | None | CLI strings only | | magickwand.js | Active, ~91 stars | v7 (current) | Rich (HEIF, WebP, EXR) | Partial async workers | Full Magick++ OOP |

Gaps wimagemagick fills:

• No project offers both CLI-style and programmatic API
• AVIF support is absent from all

Build-on opportunity: dlemstra's Magick.Native already cross-compiles ImageMagick v7 + rich delegates to WASM via Emscripten. It could serve as a foundation for the native build, with wimagemagick adding threading/SIMD builds, CLI interface, and the JS wrapper layer on top.