A PDF text extraction library that gets the hard parts right.
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Infrastructure and parsing: - raster-ocr-pipeline: trigger detection, preprocessing, Tesseract integration, assisted OCR, HOCR alignment, multi-language, performance - image-and-figure-extraction: XObjects, inline images, filter decoding, color spaces, geometry, form XObjects, transparency, figure detection - form-fields-and-annotations: AcroForm types, XFA, widget appearance streams, rich text, annotation text, output schema - pdf-encryption-and-security: R2-R6 key derivation, object-level decryption, permission flags, RustCrypto implementation approach - page-geometry-and-document-structure: page tree, all five page boxes, rotation, coordinate inversion, page labels, outlines, named destinations - optional-content-groups: OCG/OCMD visibility, usage dictionary, default state resolution, content stream marking, multilingual layer patterns - invisible-and-hidden-text: all 8 Tr modes, PDF/A invisible layer pattern, white-on-white, zero-opacity, clipped text, color tracking - malformed-pdf-repair-and-recovery: xref recovery, stream length repair, syntax tolerance, partial extraction, structured warnings Quality and metadata: - xmp-and-document-metadata: /Info vs XMP, all namespaces, RDF/XML parsing, conflict resolution, encrypted metadata, thumbnails - embedded-files-and-portfolios: EmbeddedFile streams, Filespec, AF relationships, Portfolio detection, ZUGFeRD/Factur-X, security - performance-and-streaming-architecture: mmap, lazy loading, NDJSON streaming, rayon parallelism, font caching, axum HTTP server - benchmark-and-test-methodology: CER/WER/TEDS metrics, corpus categories, reading order scoring, regression CI, public datasets Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com> |
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pdftract
A PDF text extraction library that gets the hard parts right.
What it does
- Correct reading order — layout regions are segmented and sequenced before text is emitted, handling multi-column pages, sidebars, footnotes, and mixed-layout documents without relying on PDF operator order
- Font encoding recovery — when
ToUnicodeCMaps are absent, wrong, or incomplete, pdftract works through a layered recovery pipeline: glyph name lookup via the Adobe Glyph List, font fingerprinting against known metrics and embedded checksums, and glyph outline shape matching - Structure tree extraction — PDF/UA and PDF/A documents encode their logical structure (headings, paragraphs, lists, tables, reading order) in a
StructTree; pdftract reads this directly when present, producing accurate semantic output at no extra cost - Per-page hybrid routing — each page is independently classified and routed to the appropriate pipeline: vector text extraction, full OCR, or assisted OCR where vector hints improve raster accuracy
- Structured output with provenance — the primary output is JSON carrying per-span bounding boxes, font name, size, and confidence score alongside the extracted text, not a flat string dump
Output
{
"pages": [
{
"page": 1,
"blocks": [
{ "kind": "heading", "text": "Introduction", "bbox": [72, 680, 400, 700] },
{ "kind": "paragraph", "text": "...", "bbox": [72, 640, 540, 670] }
],
"spans": [
{ "text": "Introduction", "bbox": [72, 680, 400, 700], "font": "Times-Bold", "size": 14.0, "confidence": 0.99 }
]
}
],
"metadata": { "title": "...", "author": "...", "page_count": 10 }
}
Usage
pdftract extract invoice.pdf # structured JSON to stdout
pdftract extract invoice.pdf --text # plain text to stdout
pdftract extract invoice.pdf --output out.json
pdftract serve --port 8080 # HTTP service: POST /extract
Architecture
Rust core with PyO3 Python bindings and a CLI binary. The same binary runs as a command-line tool or as an HTTP microservice — the container deployment is just pdftract serve.
See docs/research/ for technical deep-dives into the PDF specification, font encoding, glyph Unicode recovery, and tagged PDF structure. See docs/notes/ for SDK invocation examples in Python, Node.js, Go, Ruby, Java, Rust, and Bash.
Status
Early development. See docs/plan/ for the implementation roadmap.