Annotate Documents via C# / VB.NET

It's an on-premise API that seamlessly integrates document annotation features into your .NET applications. Apply graphic, text, and watermark annotations.

Document Annotation Library for .NET

Import document annotations.
Add, remove or reply to annotation comments.
Render document pages as images.
Generate document thumbnails or document image preview.
Support for default cache (local disk) or custom cache (Amazon S3, Dropbox, etc.).
Get list of supported file formats.
Fetch document information, such as, page count & file size.
Extract annotations from a document and serialize to XML format.
Remove previously added annotations from a document.
Update specific annotation properties (size, color, etc.).

Annotation Objects

Annotation type	Supported Objects
Graphic Annotation	Area, Arrow, Distance, Ellipse, Point, Polyline, Resource Redaction, TextField
Text Annotation	Highlight, Link, Replacement, Strikeout, Reduction, Underline
Watermark	Diagonal, Horizontal

Microsoft Office Formats

Microsoft Word: DOC, DOCM, DOCX, DOT, DOTM, DOTX, RTF
Microsoft Excel: XLS, XLSB, XLSM, XLSX
Microsoft PowerPoint: PPT, PPTX, PPSX, PPS
Microsoft Visio: VSD, VSDX, VSS, VST

Supported Platforms

GroupDocs.Annotation for .NET supported platforms are listed below: .NET Standard 2.0: Any type of .NET Standard 2.0 application is supported (since Q4 2019).
.NET Framework: Any type of .NET Framework version 2.0 (or later) application is supported - ASP.NET, Web Services, WinForms, WPF, and others. Full support for 32-bit and 64-bit.
Windows Azure: GroupDocs.Annotation for .NET runs on Windows Azure.
Mono: You can use GroupDocs.Annotation for .NET to build applications with Mono.

Save Annotation-only Pages of PDF File

// for this example input file ("input.pdf") must have at least 10 pages
using (Annotator annotator = new Annotator(“input.pdf”))
{
    AreaAnnotation area = new AreaAnnotation()
    {
        Box = new Rectangle(100, 100, 100, 100),
        BackgroundColor = 65535,
        PageNumber = 1
    };
    EllipseAnnotation ellipse = new EllipseAnnotation()
    {
        Box = new Rectangle(100, 100, 100, 100),
        BackgroundColor = 123456,
        PageNumber = 9
    };
    annotator.Add(new List<AnnotationBase>() { area, ellipse });
    annotator.Save(“result.pdf” new SaveOptions { OnlyAnnotatedPages = true});
}

GroupDocs.Annotation for .NET

GroupDocs