How to Add Text Annotations to PDF files using .NET
How to Add Text Annotations to PDF files using .NET
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Text annotations
PDF is a good way to share documents with people. It guarantees you that your document looks on any computer exactly the same as it is on yours. But working with documents may sometimes require an ability to manipulate with a text. To do it programmatically you can use our Annotation API for .NET. We support a various text annotations, such as:
In this article we will cover just a few of them - highlight and strikeout annotations. All others works in exactly the same way.
Highlight annotation
Highlight annotation highlights and comments selected text. This is a good way to “highlight” an import text, to bring it to the user’s attention. Highlighting is used everywhere, so this is unquestionably text annotation number one.
You have ability to specify the next properties for HighlightAnnotation type:
Call Save method with resultant document path or stream.
The following code demonstrates how to add HighlightAnnotation to the document:
//Add highlight annotation to the document from local diskusing(Annotatorannotator=newAnnotator("input.pdf")){HighlightAnnotationhighlight=newHighlightAnnotation{BackgroundColor=65535,CreatedOn=DateTime.Now,FontColor=0,Message="This is highlight annotation",Opacity=0.5,PageNumber=0,Points=newList<Point>{newPoint(80,730),newPoint(240,730),newPoint(80,650),newPoint(240,650)},Replies=newList<Reply>{newReply{Comment="First comment",RepliedOn=DateTime.Now},newReply{Comment="Second comment",RepliedOn=DateTime.Now}}};annotator.Add(highlight);annotator.Save("result.pdf");}
Strikeout annotation
Strikeout annotation marks text fragment with a strikethrough styling. When you receive a document for review and find errors or inconsistencies in it, it is very important to be able to draw the author’s attention to them. We recommend to you strikeout annotation for these purposes. Whenever the highlight annotation draws attention to the correct and important parts of the document, the strikeout annotation is usually used to cross out the wrong and unimportant parts of the document. You can check an example below.
There is an ability to specify the next properties for StrikeoutAnnotation type:
Call Save method with resultant document path or stream.
The following code demonstrates how to add StrikeoutAnnotation to the document:
//Add strikeout annotation to the document from local diskusing(Annotatorannotator=newAnnotator("input.pdf")){StrikeoutAnnotationstrikeout=newStrikeoutAnnotation{CreatedOn=DateTime.Now,FontColor=65535,BackgroundColor=16761035,Message="This is strikeout annotation",Opacity=0.7,PageNumber=0,Points=newList<Point>{newPoint(80,730),newPoint(240,730),newPoint(80,650),newPoint(240,650)},Replies=newList<Reply>{newReply{Comment="First comment",RepliedOn=DateTime.Now},newReply{Comment="Second comment",RepliedOn=DateTime.Now}}};annotator.Add(strikeout);annotator.Save("result.pdf");}
Conclusion
In short, we have learned how to add text annotations to a PDF file within .NET applications. We have introduced all the text annotations that our API supports and illustrated how and when to use them with an example. Now, you should be confident to build your own document annotator .NET application.
More resources
Advanced Usage Topics
To learn more about document annotating features, please refer to the advanced usage section.
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.
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