> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/DilwoarH/pdf-visual-regression/llms.txt
> Use this file to discover all available pages before exploring further.

# PDF Visual Regression Documentation

> Detect visual differences in PDF files with powerful page-by-page comparison and SSIM-based diff highlighting

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        <h1 className="text-4xl sm:text-5xl lg:text-6xl font-bold text-white mb-6">
          Detect visual changes in PDFs with confidence
        </h1>

        <p className="text-lg sm:text-xl text-gray-200 dark:text-gray-300 max-w-2xl mb-8">
          A Python CLI tool that performs precise page-by-page visual regression testing on PDF files using structural similarity algorithms and generates highlighted diff images.
        </p>

        <div className="flex flex-wrap gap-4">
          <a href="/quickstart" className="inline-flex items-center px-6 py-3 text-base font-semibold text-white bg-[#E63946] hover:bg-[#D62839] rounded-lg transition-colors duration-200 no-underline">
            Get Started

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            Command Reference
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            <pre className="text-sm text-gray-300">
              <code>
                {`$ python pdf_visual_diff.py \\
                                  original.pdf updated.pdf

                                Visual differences found on pages: 2, 5
                                Diff images saved to:
                                diff_output/20260304_112045_diff/`}
              </code>
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    Quick start
  </h2>

  <p className="text-base text-gray-600 dark:text-gray-400 mb-8">
    Get up and running in less than a minute
  </p>

  <Steps>
    <Step title="Install dependencies">
      Clone the repository and install the required Python packages:

      ```bash theme={null}
      git clone https://github.com/DilwoarH/pdf-visual-regression
      cd pdf-visual-regression
      pip install -r requirements.txt
      ```
    </Step>

    <Step title="Run your first comparison">
      Compare two PDF files to detect visual differences:

      ```bash theme={null}
      python pdf_visual_diff.py original.pdf updated.pdf
      ```

      The tool will analyze each page and generate highlighted diff images showing exactly where visual changes occurred.
    </Step>

    <Step title="View the results">
      Check the output directory for your diff images:

      ```bash theme={null}
      ls diff_output/
      ```

      Each difference is saved as a PNG with visual highlights marking changed regions.
    </Step>
  </Steps>
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    Explore by topic
  </h2>

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    Find what you need in our comprehensive documentation
  </p>

  <CardGroup cols={2}>
    <Card title="Installation" icon="download" href="/installation">
      Set up your environment and install all dependencies
    </Card>

    <Card title="Basic comparison" icon="code-compare" href="/usage/basic-comparison">
      Learn the fundamentals of comparing PDFs
    </Card>

    <Card title="Command reference" icon="terminal" href="/usage/command-reference">
      Complete CLI options and parameters
    </Card>

    <Card title="Configuration options" icon="sliders" href="/usage/configuration-options">
      Customize threshold and output settings
    </Card>

    <Card title="Examples" icon="book-open" href="/examples/basic-examples">
      Real-world usage patterns and scenarios
    </Card>

    <Card title="How it works" icon="gears" href="/development/how-it-works">
      Understand the SSIM algorithm and architecture
    </Card>
  </CardGroup>
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  <h2 className="text-2xl sm:text-3xl font-semibold text-gray-900 dark:text-white mb-4">
    Key features
  </h2>

  <p className="text-base text-gray-600 dark:text-gray-400 mb-8">
    Everything you need for visual regression testing
  </p>

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      <h3 className="text-lg font-semibold text-gray-900 dark:text-white mb-2">Page-by-page comparison</h3>
      <p className="text-sm text-gray-600 dark:text-gray-400">Compare each page independently and identify exactly which pages have changed</p>
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      <h3 className="text-lg font-semibold text-gray-900 dark:text-white mb-2">SSIM algorithm</h3>
      <p className="text-sm text-gray-600 dark:text-gray-400">Structural similarity detection reduces false positives from minor rendering variations</p>
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      <h3 className="text-lg font-semibold text-gray-900 dark:text-white mb-2">Visual diff images</h3>
      <p className="text-sm text-gray-600 dark:text-gray-400">Automatically generated images with highlighted regions show exactly what changed</p>
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      <h3 className="text-lg font-semibold text-gray-900 dark:text-white mb-2">Configurable thresholds</h3>
      <p className="text-sm text-gray-600 dark:text-gray-400">Adjust sensitivity to match your testing requirements</p>
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    <h2 className="text-2xl sm:text-3xl font-semibold text-gray-900 dark:text-white mb-4">
      Ready to start testing?
    </h2>

    <p className="text-base text-gray-600 dark:text-gray-400 mb-6 max-w-2xl">
      Follow our quickstart guide to install dependencies and run your first PDF comparison in under a minute.
    </p>

    <a href="/quickstart" className="inline-flex items-center px-6 py-3 text-base font-semibold text-white bg-[#E63946] hover:bg-[#D62839] rounded-lg transition-colors duration-200 no-underline">
      Get Started Now

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