Technical Consultation for GroupDocs.Comparison

GroupDocs.Comparison Product Family
1

Dear GroupDocs Support Team,
We are currently conducting a technical evaluation of GroupDocs.Comparison for PDF document comparison and plan to carry out subsequent procurement. We would appreciate your official and detailed answers to the following questions to help our evaluation and integration.

  1. Supported SDKs & Programming LanguagesWhich programming languages and official SDKs are currently supported by GroupDocs.Comparison API?Does it provide a native C++ SDK? If not, what is the official recommended way to use it in C++ applications?

  2. Pricing & LicensingPlease provide official pricing details, pricing page link, or quotation options for the API and on-premise version.What is the licensing model (developer license, server license, subscription, etc.)?

  3. Core Advantages & Limitations for PDFWhat are the key advantages and known limitations or drawbacks when comparing PDF documents using GroupDocs.Comparison API?

  4. Scanned / Image-only PDFsDoes the API support comparison of scanned / image-only PDFs?Is OCR pre-processing required or provided natively?

  5. Comparison of Images inside PDFDoes GroupDocs support comparison of images in PDF files?If supported, can it detect differences such as image addition, deletion, modification, size, position, and content changes?

  6. Vector Graphics, Shapes & ChartsFor vector graphics in PDFs (lines, shapes, charts, etc.), does GroupDocs support comparison?Can it detect changes in style, position, size, color, and layer properties?

  7. Annotations & MarkupsDoes the API support comparison of PDF annotations (comments, highlights, text boxes, stamps, shapes)?Can it identify add/delete/edit operations and retain annotation details?

  8. Background ComparisonDoes GroupDocs support comparison of PDF backgrounds (background color, background image, watermark)?Can it detect additions, deletions, and modifications?

  9. Feature Differences Between Product VersionsWhat are the differences between GroupDocs.Comparison Cloud API, On-Premise API versions in terms of:PDF comparison accuracySupport for images, graphics, annotations, backgroundsSupported formatsExport and result capabilities

  10. Advanced Comparison OptionsDoes the API support advanced comparison configurations such as:Comparing only specific page rangesComparing a defined region / area on a single pageIgnoring certain content types (watermarks, headers, footers)

  11. Supported Text & Format ChangesWhat kinds of font and format changes can GroupDocs API detect?Such as font name, size, bold, italic, underline, color, strikethrough, highlight, character spacing, etc.Please list all detectable text style changes that can be identified and returned in results.

  12. File LimitationsWhat are the limitations for PDF files when using Cloud API and On-Premise API:Single file size limitMaximum page count per documentSingle page dimension / resolution limitSupport for encrypted / password-protected PDFsLimitations for complex PDFs (complex layouts, multi-layer content, transparency, etc.)Performance and speed limitations

Thank you for your official response to support our technical evaluation and procurement process.Best regards

2

hi @chaohui ,
Thank you for your detailed questions. Let me try to provide one by one answers:

  1. Supported SDKs & Programming Languages
    GroupDocs.Comparison is available as .NET (C#), Java, Node.js (via Java backend), Python (via .NET bridge) and there is no native C++ SDK. So either you can wrap the SDK as a service (e.g., a microservice in .NET or Java) and call it from C++ via HTTP, or use a cloud API (REST-based).

  2. Pricing & Licensing
    GroupDocs.Comparison is offered in the following models:

  • Developer License (per developer)
  • Site/Server License (production deployment)
  • Cloud API subscription (usage-based plans)

Official pricing and licensing details are available here https://purchase.groupdocs.com/
We recommend purchasing a free trial license and performing the required comparison tests to evaluate the results.

  1. Core Advantages & Limitations for PDF
    The result PDF is a reconstructed visualization of changes. If the source/target layout differs (line wrapping, reflow, coordinate differences), the reconstructed “before” and “after” parts may not occupy perfectly separated regions. Text replacement is typically shown as “deleted old text” + “inserted new text”. Both pieces can be rendered in the output PDF, and they may overlap neighboring paragraphs/lines when wrapping/coordinates change between versions.
  • Currently, we are working on a new feature that will allow comparison differences to be viewed side by side. The resulting PDF will contain the first page from the source document with highlighted deletions, and the second page from the target document with highlighted insertions. This approach will make the differences much clearer and help avoid clutter when there are many changes.

  1. Scanned / Image-only PDFs
    Scanned or image-only PDFs are supported only as images, currently The system does not include built-in OCR functionality.

  2. Comparison of Images inside PDF
    Yes, images inside PDFs are supported. It can detect:

  • inserted and deleted images,
  • image style changes such as size (width/height).

For image content, the engine uses a lightweight similarity check for matching (not full pixel-by-pixel diff). Content changes are typically reflected as image replacement (deleted + inserted) rather than a dedicated “modified image content” change type.
Technically, using SDK it is possible to render PDF document pages as images and then compare the images separately. In such a case, the engine uses pixel-level detection to identify content changes.

  1. Vector Graphics, Shapes & Charts
    GroupDocs.Comparison for PDF currently does not provide dedicated comparison for arbitrary vector graphics objects (lines, shapes, charts) as a separate change category.

  2. Annotations & Markups
    SDK supports PDF annotation comparison with partial coverage. Currently, it compares Text and Popup annotations and can detect add/delete/edit operations (inserted, deleted, modified). Annotation types like highlights, free-text text boxes, stamps, and shape-based markups are not currently covered as dedicated comparison types.

  3. Background Comparison
    GroupDocs.Comparison does not currently provide a dedicated, full-featured PDF background comparison mode (background color/image/watermark as a separate category).

    1. Advanced Comparison Options
      Specific page ranges current is not available as a direct compare option, but we have such task in the backlog. Sdk has settings that allow configuration of specific content types, for example ignoring headers and footers.

    2. Supported Text & Format Changes
      With setting CompareOptions.DetectStyleChanges GroupDocs.Comparison returns style changes via StyleChangeInfo entries (PropertyName, OldValue, NewValue). Detectable text-level style changes include: FontName, FontSize, ForegroundColor, BackgroundColor, Underline, Strikeout, Subscript, Superscript, LineSpacing, Alignment, IsHyperlink, HyperlinkUrl.

There will be one more response about the cloud API details. Overall we recommend testing your real-world documents with SDK modes to determine the best fit for your workload.

3

hi @chaohui ,
Here is an additional reply regarding Cloud API–specific questions:

  1. Feature Differences Between Product Versions (Cloud API vs On-Premise API)
    The Cloud API supports a more limited set of methods compared to the on-premise SDK, and accordingly provides fewer configuration options.

    1. File Limitations (Cloud API vs On-Premise API)
      There are no strict file size limits, except for request timeouts. Each request must be completed within 5 minutes. In practice, this introduces a file size limitation—typically around 10–20 MB—since larger files may not be processed within the allowed time. However, this also depends on the specific file format and content.
      Additionally, processing speed in the Cloud environment is generally slower compared to desktop or self-hosted environments, as shared server resources are used and CPU performance may vary.