public PdfCircleAnnotationFacade AddCircleAnnotation(
    PdfRectangle rect
)

Public Function AddCircleAnnotation(
    rect As PdfRectangle
) As PdfCircleAnnotationFacade

using (PdfDocumentProcessor processor = new PdfDocumentProcessor())
{
    // Load a document
    processor.LoadDocument("..\\..\\Document.pdf");

    // Access the first page properties
    PdfPageFacade pageFacade = processor.DocumentFacade.Pages[0];

    // Define an annotation area
    PdfRectangle rectangle = new PdfRectangle(663, 526, 763, 576);

    // Create a circle annotation
    PdfCircleAnnotationFacade circleAnnotation = pageFacade.AddCircleAnnotation(rectangle);

    // Specify annotation parameters
    circleAnnotation.Author = "Nancy Davolio";
    circleAnnotation.Contents = "Made in PDF Document API";

    // Save the result
    processor.SaveDocument("..\\..\\Result.pdf");
}

Using processor As New PdfDocumentProcessor()
  ' Load a document
  processor.LoadDocument("..\..\Document.pdf")

  ' Access the first page properties
  Dim pageFacade As PdfPageFacade = processor.DocumentFacade.Pages(0)

  ' Define an annotation area
  Dim rectangle As New PdfRectangle(663, 526, 763, 576)

  ' Create a circle annotation
  Dim circleAnnotation As PdfCircleAnnotationFacade = pageFacade.AddCircleAnnotation(rectangle)

  ' Specify annotation parameters
  circleAnnotation.Author = "Nancy Davolio"
  circleAnnotation.Contents = "Made in PDF Document API"

  ' Save the result
  processor.SaveDocument("..\..\Result.pdf")
End Using