The PdfComparer class in Free Spire.PDF provides a high-level abstraction for PDF comparison operations. It automaticcally analyzes differences between documents (including text additions, deletions, and modifications) and generates a new PDF highlighting these changes. ### Visual Representation of Differences

The comparison output uses color-coded annotations: - Identical content: Displayed without highlighting

• Added content: Marked with yellow highlights
• Removed content: Indicated with red strikethroughs

Library Installation

Install via NuGet Package Manager: 1. Right-click your project and select "Manage NuGet Packages" 2. Search for "FreeSpire.PDF" and install the latest stable version

Alternatively, use the Package Manager Console: ``` Install-Package FreeSpire.PDF

Implementation in C#
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The comparison process involves four straightforward steps: 1. Create `PdfDocument` instances for both files
2. Initialize `PdfComparer` with the loaded documents
3. Execute the comparison and save results
4. Release document resources

using Spire.Pdf; using Spire.Pdf.Comparison;

class PdfComparator { static void ExecuteComparison() { using (var docA = new PdfDocument("Contract_v1.pdf")) using (var docB = new PdfDocument("Contract_v2.pdf")) { var analyzer = new PdfComparer(docA, docB); analyzer.GenerateDiffReport("VersionComparison.pdf"); } } }

Note: The free version has page limitations but suffices for basic comparison needs. This approach eliminates manual text extraction and provides immediately readable visual output. </div>