Add underline annotation

Underline annotation marks text with a underline styling like shown at the picture below. 

There is an ability to specify the next properties for UnderlineAnnotation type:

  • FontColor - color of annotation text;
  • Opacity - allows to set annotation opacity;
  • Points - annotation positions set by array of points.

Follow these steps to add Underline annotation to document:

  • Instantiate Annotator object with input document path or stream;
  • Instantiate UnderlineAnnotation object with desired properties (position, page number, etc);
  • Call Add method and pass UnderlineAnnotation object;
  • Call Save method with resultant document path or stream.

The following code demonstrates how to add UnderlineAnnotation to the document:

//Add underline annotation to the document from local disk
using (Annotator annotator = new Annotator("input.pdf"))
{
	UnderlineAnnotation underline = new UnderlineAnnotation
    {
    	CreatedOn = DateTime.Now,
        FontColor = 65535,
        Message = "This is underline annotation",
        Opacity = 0.7,
        PageNumber = 0,
        Points = new List<Point>
        {
        	new Point(80, 730), new Point(240, 730), new Point(80, 650), new Point(240, 650)
        },
        Replies = new List<Reply>
        {
        	new Reply
            {
            	Comment = "First comment",
                RepliedOn = DateTime.Now
            },
            new Reply
            {
            	Comment = "Second comment",
                RepliedOn = DateTime.Now
            }
        }
    };
    annotator.Add(underline);
    annotator.Save("result.pdf");
}

More resources

Advanced Usage Topics

To learn more about document annotating features, please refer to the advanced usage section.

GitHub Examples

You may easily run the code above and see the feature in action in our GitHub examples:

Free Online App

Along with full-featured .NET library we provide simple but powerful free Apps. You are welcome to annotate your PDF, DOC or DOCX, XLS or XLSX, PPT or PPTX, PNG and other documents with free to use online GroupDocs Annotation App.