poppler/pdftotext does not carry Tz (horizontal scaling) across
BT/ET boundaries, causing words to appear on separate lines.
Replace per-word BT blocks (via fpdf2's cell/set_stretching API)
with a single BT block per line using raw PDF operators. Each
non-last word gets a trailing space with Tz calculated to span
exactly to the next word's start position.
When Tesseract completely fails to detect text rotation (no textangle,
slope=0), it produces garbage text in tall-narrow bounding boxes. Add
an aspect ratio plausibility check that compares the OCR bounding box
shape to the expected shape of the rendered text (accounting for
baseline slope). Lines where the ratio of aspect ratios is < 0.1 are
suppressed.
Uses a fast path (width >= height) to skip the expensive font
measurement for the common case of normal horizontal text.
Tesseract doesn't output the textangle hOCR attribute for 90-degree
rotated text. Instead, the rotation is encoded as extreme baseline
slope values (e.g., 462.2). Without detecting this, the renderer used
the axis-aligned bounding box height as line_size_height, producing
font sizes of 2000+ pt instead of ~10 pt.
Detect steep baseline slopes (|slope| > 1.0, i.e., > 45° from
horizontal) and extract the effective text rotation angle via atan().
The meaningless slope/intercept values are then replaced with
font-metrics-based defaults.
The previous fix (e62e73e4) only corrected text_rendering_mode →
text_mode in the single-page Fpdf2PdfRenderer, but the main OCR
pipeline uses Fpdf2MultiPageRenderer which still had the old
attribute name. Since fpdf2 has no text_rendering_mode property,
setting it silently created a no-op attribute while text_mode stayed
at FILL — so 3 Tr (invisible text) was never emitted.
Fixes#1631, #1632
Fixes#1630 where --redo-ocr would shift OCR text vertically on PDFs
with non-zero mediabox origins (e.g., [0, 100, width, height+100]).
The bug occurred in _graft_fpdf2_text_layer where the Form XObject BBox
was set to the text layer's mediabox [0, 0, w, h] instead of the base
page's mediabox [0, 100, w, h+100]. This caused a coordinate mismatch
between the BBox and the transformation matrix, resulting in text being
positioned incorrectly.
The fix changes line 450 in _graft.py to use base_mediabox instead of
mediabox, making the fpdf2 renderer consistent with the sandwich renderer
which already used base_mediabox correctly.
This issue commonly affected:
- JSTOR PDFs (generated by iText with cropping)
- Cropped PDFs from various tools
- PDFs with non-standard coordinate systems
Added regression test that creates a PDF with offset mediabox origin
and verifies --redo-ocr preserves coordinates correctly.
- Prioritize uv over pip throughout, with uv as the recommended installer
- Update repology badges: Debian 13, Ubuntu 24.04, Fedora 40/41
- Make Python 3.12 the default (3.11 still supported)
- Promote Homebrew as full-featured option for macOS and Linux
- Add dependency summary table aligned with maintainers.md
- Document uharfbuzz and fonts-noto requirements
- Remove outdated warnings and simplify 32-bit section
Ghostscript may fail when asked to rasterize at very low DPI values
(below 10 on either axis). This adds a workaround that uses a minimum
of 10 DPI for the Ghostscript call, then resizes the output image to
match the dimensions that would have resulted from the original low
DPI request.
Fixes#1612
Make filter_pdf_page, get_ocr_engine, and optimize_pdf return
non-optional types by handling None cases explicitly: raise errors
for required results, return sensible defaults for optional ones.
Use a Pydantic field validator to convert string input to list[str]
during OcrOptions construction, simplifying the type from
`str | list[str] | None` to `list[str] | None`. Security validation
(path injection check) now happens at construction rather than in
check_options_preprocessing().
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)
FlateDecode+DCTDecode compressed images are essentially deflated JPEGs,
typically created by OCRmyPDF's optimizer. This change ensures pdfinfo
correctly identifies them and should_visible_page_image_use_jpg treats
them as JPEG-origin images, allowing JPEG output when appropriate.
pypdfium was not converting images to the correct colorspace/mode based
on the raster_device parameter. For example, pngmono should produce a
1-bit image, but pypdfium was outputting full-color or grayscale images.
This caused images to be incorrectly promoted to PNG instead of being
preserved as CCITT/JBIG2 when using --force-ocr with pypdfium, because
the optimizer relies on the image being in the correct mode.
Changes:
- Render in grayscale for pngmono device (better input for 1-bit conversion)
- Add mode conversion to match Ghostscript's native device output:
- pngmono: convert to mode '1' (1-bit)
- pnggray/jpeggray: convert to mode 'L' (8-bit grayscale)
- png256: convert to mode 'P' (8-bit indexed)
- png16m/jpeg: convert to mode 'RGB'
Add new options: --mode, --ocr-engine, --rasterizer,
--continue-on-soft-render-error, --tesseract-non-ocr-timeout,
--tesseract-downsample-large-images, --tesseract-downsample-above,
--unpaper-args (fish), --plugin (fish).
Update --output-type to include 'auto' as default.
Update --pdf-renderer to include 'fpdf2' and mark hocr as deprecated.
Remove non-working options: --remove-background, --threshold.
The test expected MediaBox preservation for pdfa output, but this only
works when verapdf is available for speculative PDF/A conversion.
Without verapdf (Linux/Windows CI), Ghostscript normalizes the MediaBox.
Also convert pikepdf.Array to list in assertions for clearer error
messages, avoiding pytest repr issues with pikepdf objects.
multiprocessing.Queue is a factory function, not a type, so it cannot
be used with the runtime | union operator. Move Queue, UserInit, and
WorkerInit type aliases into TYPE_CHECKING block to avoid evaluation
at runtime.
Python 3.11 is now the minimum supported version. This aligns with
the codebase's use of StrEnum (introduced in 3.11) and removes
compatibility shims that were only needed for older versions.
Document the new v17 API style where OcrOptions can be passed directly
to ocr(). Mark the positional argument style as legacy API for <v17
compatibility. Update examples to use modern syntax.
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.
The pypdfium rasterizer was producing output images that differed by 1
pixel compared to Ghostscript due to floating-point precision issues in
dimension calculations.
Root cause:
- pypdfium used harmonic mean of x/y DPI to calculate a single scale
factor, losing the distinction between x and y DPI
- No DPI rounding like Ghostscript's 6-decimal precision
- Compound rounding errors when converting points to pixels
Solution:
1. Round DPI to 6 decimals to match Ghostscript's precision
2. Calculate expected output dimensions using separate x/y DPI values
3. Handle dimension swapping for 90°/270° rotations
4. Resize output image if off by 1-2 pixels (graceful correction)
This ensures pixel-perfect matching with Ghostscript while being
minimally invasive and only resizing when necessary.
Changes:
- Modified _render_page_to_bitmap() to calculate expected dimensions
- Modified _process_image_for_output() to correct small discrepancies
- Updated rasterize_pdf_page() to pass dimensions through pipeline
- Parametrized rotation tests to run with both rasterizers
All 45 rotation tests now pass with both pypdfium and ghostscript.
Fixes test_rotated_skew_timeout with pypdfium rasterizer.
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().
James R. Barlow
dependabot[bot]andGitHub