https://github.com/JoshData/pdf-diff

A PDF comparison utility in Python.
https://github.com/JoshData/pdf-diff

Last synced: 27 days ago
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A PDF comparison utility in Python.

• Host: GitHub
• URL: https://github.com/JoshData/pdf-diff
• Owner: JoshData
• License: cc0-1.0
• Created: 2014-06-09T23:36:52.000Z (almost 11 years ago)
• Default Branch: primary
• Last Pushed: 2024-12-06T19:06:30.000Z (5 months ago)
• Last Synced: 2025-04-06T14:06:48.830Z (29 days ago)
• Language: Python
• Homepage:
• Size: 263 KB
• Stars: 470
• Watchers: 12
• Forks: 69
• Open Issues: 25
• Metadata Files:
  • Readme: README.md
  • Contributing: CONTRIBUTING.md
  • License: LICENSE

Awesome Lists containing this project

• awesome-pdf - pdf-diff

README

        
# pdf-diff

Finds differences between two PDF documents:

1. Compares the text layers of two PDF documents and outputs the bounding boxes of changed text in JSON.

2. Rasterizes the changed pages in the PDFs to a PNG and draws red outlines around changed text.

![Example Image Output](example.png)

The script is written in Python 3, and it relies on the `pdftotext` program.

## Requirements

    

    libxml2 >= 2.7.0, libxslt >= 1.1.23, poppler

## Requirements installation for Ubuntu:

    

    sudo apt-get install python3-lxml poppler-utils

## Requirements installation for OS X:

    

    brew install libxml2 libxslt poppler

## Installation

From PyPI:

    pip install pdf-diff

From source:

    sudo python3 setup.py install

## Running

Turn two PDFs into one large PNG image showing the differences:

    pdf-diff before.pdf after.pdf > comparison_output.png

## Maintainer Notes

To deploy:

	python3 -m pip install --user --upgrade setuptools wheel twine

	python3 setup.py sdist bdist_wheel

	python3 -m twine upload dist/*

## Function flow diagram

```

compute_changes

│

├── serialize_pdf (called twice)

│    ├── pdf_to_bboxes

│    ├── mark_eol_hyphens

│    │    └── mark_eol_hyphen

│    └── Processes bounding boxes and text

│

├── perform_diff

│    └── Calls external `fast_diff_match_patch`

│

└── process_hunks

     ├── Iterates through diff hunks

     └── mark_difference (called multiple times)

render_changes

│

├── simplify_changes

├── make_pages_images

│    └── pdftopng (converts PDF pages to images)

├── realign_pages

│    ├── Splits pages into sub-pages

│    └── Adjusts box coordinates

├── draw_red_boxes

│    └── Annotates images with rectangles or lines

└── zealous_crop

     └── Crops the image to reduce unnecessary margins

stack_pages

│

└── Combines processed images into a final output

```