Fix OCR on Qubes: PyMuPDF required TESSDATA_PREFIX

PyMuPDF versions lower than 1.22.5 pass the tesseract data path as
an argument to `pixmap.pdfocr_tobytes()` [1], but lower versions require
setting instead the TESSDATA_PREFIX environment variable [2].

Because on Qubes the pixels to pdf conversion happens on the host and
Qubes has a lower PyMuPDF package version, we need to pass instead via
environment variable.

NOTE: the TESSDATA_PREFIX env. variable was set in dangerzone-cli
instead of closer to the calling method in `doc_to_pixels.py` since
PyMuPDF reads this variable as soon as the fitz module is imported
[3][4].

[1]: https://pymupdf.readthedocs.io/en/latest/pixmap.html#Pixmap.pdfocr_tobytes
[2]: https://pymupdf.readthedocs.io/en/latest/installation.html#enabling-integrated-ocr-support
[3]: https://github.com/pymupdf/PyMuPDF/discussions/2439
[4]: https://github.com/pymupdf/PyMuPDF/blob/5d6a7db/src/__init__.py#L159

Fixes #682
This commit is contained in:
deeplow 2024-01-24 13:50:22 +00:00
parent d1afe4c30a
commit 6006beeb03
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GPG key ID: 577982871529A52A
2 changed files with 18 additions and 6 deletions

View file

@ -57,11 +57,19 @@ class PixelsToPDF(DangerzoneConverter):
self.update_progress(
f"Converting page {page_num}/{num_pages} from pixels to searchable PDF"
)
page_pdf_bytes = pixmap.pdfocr_tobytes(
compress=True,
language=ocr_lang,
tessdata=get_tessdata_dir(),
)
if int(fitz.version[2]) >= 20230621000001:
page_pdf_bytes = pixmap.pdfocr_tobytes(
compress=True,
language=ocr_lang,
tessdata=get_tessdata_dir(),
)
else:
# XXX method signature changed in v1.22.5 to add tessdata arg
# TODO remove after oldest distro has PyMuPDF >= v1.22.5
page_pdf_bytes = pixmap.pdfocr_tobytes(
compress=True,
language=ocr_lang,
)
ocr_pdf = fitz.open("pdf", page_pdf_bytes)
else: # Don't OCR
self.update_progress(

View file

@ -1,10 +1,14 @@
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# Load dangerzone module and resources from the source code tree
import os
import sys
# XXX workaround lack of tessdata path arg for PyMuPDF < v1.22.5
# for context see https://github.com/freedomofpress/dangerzone/issues/682
os.environ["TESSDATA_PREFIX"] = os.environ.get("TESSDATA_PREFIX", "/usr/share/tesseract/tessdata")
# Load dangerzone module and resources from the source code tree
sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
sys.dangerzone_dev = True