diff-pdf

Compare PDFs, indicating changes using return codes (0 = no difference, 1 = PDFs differ)

$ diff-pdf [path/to/a.pdf] [path/to/b.pdf]

$ diff-pdf --output-diff=[path/to/diff.pdf] [path/to/a.pdf] [path/to/b.pdf]

$ diff-pdf --view [path/to/a.pdf] [path/to/b.pdf]

diff-pdf [options] <PDF_file_1> <PDF_file_2>

--version
    Display version information and exit.

--help
    Display help message and exit.

--output-diff <file>
    Save the diff image to the specified file.

--threshold <value>
    Set the threshold for difference detection. Default value is based on image comparison algorithm. Lower values detect even small changes.

--zoom <percentage>
    Set the zoom level for the GUI. Default is 100.

--fontname <font name>
    Set the font name to use when rendering text. By default it picks a suitable font.

--freetype-hints (none|slight|full)
    Set the level of freetype hints. Defaults to slight.

--pages <page_range>
    Specify a range of pages to compare (e.g., '1-5', '3', 'all').

The diff-pdf command is a utility designed for visually comparing two PDF files. It renders both PDFs as images and then highlights the differences between them. This allows users to quickly identify changes between versions of a document, making it useful for reviewing updates, identifying errors, or verifying document integrity. The command provides a graphical user interface (GUI) displaying the two PDFs side-by-side, with differences highlighted using color-coded rectangles. diff-pdf is particularly valuable when changes are subtle or involve formatting modifications that are difficult to detect using text-based diff tools. It supports multiple pages, allowing users to navigate through the entire document. The tool simplifies the process of PDF comparison, providing a clear and intuitive way to visualize differences. This greatly enhances productivity and accuracy in document review workflows. The command is typically used in software development, documentation, and legal fields, where precise PDF comparison is crucial. It offers a significant advantage over manual comparison methods, saving time and reducing the likelihood of overlooking important modifications. The graphical interface makes it easier to interpret the changes and communicate them to others, improving collaboration and decision-making.

The accuracy of the comparison depends on the rendering quality of the PDF files.
Differences in font embedding or image compression can sometimes lead to false positives.
Requires Python with the PyQt framework.

diff-pdf returns 0 if no differences are found, and a non-zero value if differences are detected or an error occurs.

diff-pdf requires the Python programming language, the PyQt graphical user interface toolkit, and the PDF rendering library (often Poppler or MuPDF).
Ensure that these dependencies are installed before using diff-pdf.

The diff-pdf command was developed to address the need for a visual comparison tool for PDF documents.
Traditional text-based diff utilities are inadequate for identifying formatting and layout changes in PDF files.
The command has evolved over time to improve its accuracy and usability.
It has become a popular tool for document review and quality control.

pdfinfo(1), pdftotext(1), compare(1)