Writing the output PDF to stdout (ocrmypdf in.pdf -) previously relied on
an honor system: no in-process code -- third-party libraries, plugins, or
stray print() calls -- was supposed to write to stdout, enforced only
indirectly. A single accidental write to fd 1 would silently corrupt the
output PDF.
Enforce this at the OS level. At CLI startup, before plugins load or any
worker process/thread starts, save the real stdout via os.dup() and point
fd 1 at stderr, so stray writes are diverted to stderr while only the final
"produce the PDF" step writes to the preserved descriptor. Exposed as the
opt-in public API function configure_stdout_protection(), mirroring
configure_logging(); it is not enabled inside ocr() so in-process library
users keep their own stdout.
Also fix check_requested_output_file() to test the preserved real stdout
for tty-ness, since after the redirect sys.stdout reports stderr's status.
Fold unreleased v17.7.2 notes into v17.8.0.
Allow users to bypass the TaggedPDFError when processing Tagged PDFs
by setting --tagged-pdf-mode=ignore. This is useful when users know
they want to OCR a Tagged PDF despite the warning.
- 'default': Error if --mode is default, otherwise warn (current behavior)
- 'ignore': Always warn but continue processing (never error)
Allow passing an OcrOptions object directly to ocr() as the first
positional argument, providing a cleaner API for programmatic use.
The old-style API with individual parameters remains fully supported.
Introduce --ocr-engine option to select between OCR engines:
- 'auto' (default): Uses Tesseract
- 'tesseract': Explicit Tesseract selection
- 'none': Skip OCR entirely (for PDF processing only)
Key changes:
- Extend OcrEngine ABC with generate_ocr() and supports_generate_ocr()
for direct OcrElement tree output (bypasses hOCR)
- Add get_ocr_engine(options) hook parameter for engine selection
- Implement NullOcrEngine for --ocr-engine none
- Export OcrElement, OcrClass, BoundingBox from ocrmypdf package
- Add ocr_tree support to grafting pipeline
This prepares the foundation for pluggable OCR engines while maintaining
full backward compatibility with existing Tesseract-based workflows.
James R. Barlow
James R. Barlow
Martin Wind
Martin Wind