$ show photopea/UTIF.js
UTIF.js is a comprehensive, single-file JavaScript library for decoding and encoding TIFF, EXIF, DNG, CR2, NEF, and other TIFF-based image formats. It is the primary TIFF library used by the Photopea online image editor. The library handles a wide variety of compression schemes (JPEG, LZW, PackBits, Fax, Deflate, Nikon, Panasonic, etc.) and supports various bit depths, color spaces, and photometric interpretations. It provides a straightforward API: `UTIF.decode()` for parsing TIFF headers, `UTIF.decodeImage()` for decompressing pixel data, and `UTIF.toRGBA8()` for converting to RGBA. The code is monolithic, embedding its own JPEG decoder and many other decoders directly in a single file. While functional and battle-tested, the code is dense, uses ES5 patterns, and contains many minified-like variable names, making it less readable and maintainable. The library depends on the outdated `pako` v1.x for deflate compression. It is a mature, production-ready library but with medium technical drift and a maintenance status that appears active (last commit dated 2026-05-04, though this date is likely a mistake).
The LLM identified 2 files worth highlighting for reuse:
The `UTIF._binBE` and `UTIF._binLE` objects provide a clean, self-contained set of binary read/write functions for big-endian and little-endian data. They handle unsigned/signed integers, floats, doubles, ASCII strings, and zero-finding. They are implemented using typed arrays for efficiency and are completely independent of the rest of the library. An engineer could extract these into a separate npm package for binary parsing in any JavaScript project.
The `UTIF._inflateRaw` function is a standalone, self-contained implementation of raw deflate decompression (RFC 1951). It is a minified but functional inflater that handles dynamic and fixed Huffman tables, block types, and LZ77 copying. It does not depend on any external library and can be extracted and reused in any JavaScript environment for decompressing raw deflate streams.