The optimizer is best-effort: any image it cannot process is left
unchanged in the output, which remains valid. Previously, an extraction
failure (e.g. an exotic colorspace pikepdf cannot transcode) was logged
with log.exception, printing a full traceback at ERROR level that alarmed
users even though nothing was wrong with the output (issue #846).
Trap such failures with a concise warning that the image was left
unchanged and the output is still valid, and demote the traceback to
debug verbosity for diagnosis.
The 2024 guard against runaway recursion in _find_image_xrefs_container
only deduplicated image xrefs, but Form XObject xrefs are never added to
include_xrefs/exclude_xrefs, so a self-referential or DAG-shaped Form
graph re-entered every branch until the depth limit fired -- producing
the reported flood of warnings (and minutes-long hangs) on PowerPoint
exports.
Thread a visited_forms set through the recursion so each Form XObject is
descended into at most once per document. With memoization in place the
depth limit is no longer a cycle defense, so demote its log to debug.
Add a regression test that synthesises a circular-Form PDF from the
existing formxobject.pdf fixture (no new binary fixture, no license
issues) and asserts zero "Recursion depth exceeded" warnings.
The jpg_quality and png_quality options default to None in the pydantic
model, but the fallback check only handled == 0. This caused a TypeError
when calling ocrmypdf.ocr() with optimize >= 2 without explicitly
setting quality values. Fixes#1641.
Images with [FlateDecode, DCTDecode] filter chain were incorrectly
being marked for additional FlateDecode compression, resulting in
double-compressed data and invalid output PDFs.
Add _already_flate_encoded() helper to check if an image already has
FlateDecode in its filter chain, and skip such images in
_find_deflatable_jpeg().
Lossy JBIG2 has been removed due to well-documented risks of character
substitution errors (e.g., 6/8 confusion). The --jbig2-lossy and
--jbig2-page-group-size arguments are now deprecated and ignored with
a warning.
Changes:
- Remove jbig2_lossy and jbig2_page_group_size from OCROptions
- Simplify optimize.py to use single-image JBIG2 encoding only
(no symbol dictionaries/JBIG2Globals)
- Remove convert_group() from jbig2enc.py
- Deprecate CLI args with warnings for backward compatibility
- Update documentation to explain lossless-only JBIG2
The executor system was built around passing only a single
argument to workers, which was
always PageContext. For other tasks, all actual arguments were packed in
a tuple, which meant we needed intermediate functions to unpack the
tuple.
The situation is now rationlized and resembles how Python handles
argument passing to familiar multiprocessing tools.
James R. Barlow
