While reviewing or to attract viewer to an important content, you may need to highlight some part of the document. As a developer, you can automate this feature by using highlight annotations within your applications. In this article, you will learn how to highlight text and any area in PDF files using C#.
The following topics are covered below:
.NET API to Highlight in PDF
GroupDocs.Annotation provides .NET API that allows manipulating annotations and their automation in documents within .NET applications. I am using this API to highlight text in the PDF file in the example of this article.
PM> Install-Package GroupDocs.Annotation
Highlight in PDF using C#
The following are the steps to highlight text or any area in PDF from your .NET application.
- Load the source PDF document using Annotator class.
- Create the HighlightAnnotation object.
- Define the highlight properties like the color, opacity, page number, and points.
- Add the defined highlighting to the loaded PDF document using Add method.
- Save the annotated PDF using Save method.
Note: You may change the highlight color, opacity, and other properties.
The following code sample shows how to highlight the text in PDF programmatically using C#.
The following is the output of the above code.
Get a Free API License
You can get a free temporary license in order to use the API without the evaluation limitations.
To sum up, we have learned how to add highlight annotation in PDF files programmatically using C#. Additionally, we can change the highlight color, opacity, and other properties. Many different types of annotations can be added in a similar way using the same API.