Organize Annotations in PDF Document API
- 7 minutes to read
The PDF Document API supports the following annotation types:
- Link Annotations
- A hypertext link to a URI or a destination (a reference to a page with specific view parameters).
- Markup Annotations
Annotations used to mark up document content. The following markups are available:
- Text Markup (text highlight, underline, strikeout)
- Sticky Note
- Caret
- Rubber Stamp
- Shape (circle, square)
- File Attachment
- Free Text (text box, callout, typewriter)
- Ink
- Path (line, polyline, polygon)
- Redaction Annotations
- Tools used to remove sensitive or confidential information from a document. These annotations allow users to mark areas of text, images, or other content for redaction.
You can create, delete, and flatten annotations, edit their content, and add related comments and reviews.
The PdfPageFacade.Annotations property retrieves all page annotation properties. Use the PdfDocumentFacade.Pages property to obtain the PdfPageFacade instance.
This topic describes the following features common to all annotation types:
- Edit annotations
- Add comments to annotations
- Add reviews to annotations
- Flatten annotations
- Remove annotations
Refer to the corresponding topic from the table below for more detailed information on the required annotation type.
| Annotation Type | Base Class | More Information |
|---|---|---|
| Link Annotation | Pdf |
Links in PDF Documents |
| File Attachment Annotations | Pdf |
Attach Files to a PDF |
| Markup Annotations | Pdf |
Manage Markup Annotations |
| Redaction Annotations | Pdf |
Manage Redaction |
#Edit Annotations
The PdfPageFacade.Annotations property returns all page annotation properties. You can filter annotation properties, cast them to the corresponding class, and use class properties to modify annotation parameters.
The code sample below changes annotations created in the previous example, so they appear as follows:
using DevExpress.Pdf;
using System.Linq;
using (PdfDocumentProcessor processor = new PdfDocumentProcessor())
{
// Load a document
processor.LoadDocument("..\\..\\Result.pdf");
// Access the first page properties
PdfPageFacade pageFacade = processor.DocumentFacade.Pages[0];
// Obtain all free text annotations
var freeTextAnnotations = pageFacade.Annotations.Where
(annotation => annotation.Type == PdfAnnotationType.FreeText);
foreach (PdfFreeTextAnnotationFacade freeText in freeTextAnnotations)
{
// Change border parameters and text justification
freeText.InteriorColor = new PdfRGBColor(0.36, 0.54, 0.66);
freeText.BorderWidth = 0.5;
freeText.TextJustification = PdfTextJustification.Centered;
}
// Retrieve all circle annotations
var circleAnnotations = pageFacade.Annotations.Where
(annotation => annotation.Type == PdfAnnotationType.Circle);
foreach (PdfCircleAnnotationFacade pdfCircle in circleAnnotations)
{
// Change border style and color
pdfCircle.BorderStyle = PdfBorderStyle.Dash;
pdfCircle.Color = new PdfRGBColor(0.52, 0.87, 0.01);
}
// Get all rubber stamps
var rubberStampAnnotations = pageFacade.Annotations.Where
(annotation => annotation.Type == PdfAnnotationType.RubberStamp);
foreach (PdfRubberStampAnnotationFacade pdfRubberStamp in rubberStampAnnotations)
{
// Generate a stamp from another document’s page
pdfRubberStamp.SetCustomIcon("..\\..\\Demo.pdf", 4);
}
// Obtain all file attachments
var fileAttachments = pageFacade.Annotations.Where
(annotation => annotation.Type == PdfAnnotationType.FileAttachment);
foreach (PdfFileAttachmentAnnotationFacade fileAttachment in fileAttachments)
{
// Change the icon and its color
fileAttachment.Color = new PdfRGBColor(0.83, 0.13, 0.18);
fileAttachment.IconName = PdfFileAttachmentAnnotationIconName.Tag;
}
// Save the result
processor.SaveDocument("..\\..\\Result_1.pdf");
}
#Add Comments to Annotations
Use API from the table below to add comments to markup annotations:
| API | Description |
|---|---|
| Pdf |
Adds a comment to the annotation. This method returns the Pdf |
| Pdf |
Obtains all annotation comments. |
| Pdf |
Creates a nested comment. |
| Pdf |
Gets all nested comments added to the comment. |
| Pdf |
Adds a review to the comment. Use the Pdf |
The code sample below adds two nested comments to all sticky notes (the document in opened in WinForms PDF Viewer):
using (PdfDocumentProcessor processor = new PdfDocumentProcessor())
{
// Load a document
processor.LoadDocument("..\\..\\Document.pdf");
// Access the first page properties
PdfPageFacade pageFacade = processor.DocumentFacade.Pages[0];
// Retrieve all text annotations
var stickyNotes = pageFacade.Annotations.Where
(annotation => annotation.Type == PdfAnnotationType.Text);
foreach (PdfTextAnnotationFacade stickyNote in stickyNotes)
{
// Add comments
AddAnnotationComments(stickyNote);
}
// Save the result
processor.SaveDocument("..\\..\\Result.pdf");
}
private static void AddAnnotationComments(PdfMarkupAnnotationFacade annotation)
{
PdfMarkupAnnotationComment comment =
annotation.AddReply("Reviewer", "Done");
comment.Subject = "Proofread";
PdfMarkupAnnotationComment nestedComment =
comment.AddReply(annotation.Author, "Thanks");
nestedComment.Subject = "Reviewed";
}
#Add Reviews to Annotations
Call the PdfMarkupAnnotationFacade.AddReview method to add a review to the markup annotation. The PdfMarkupAnnotationFacade.Reviews property obtains all annotation reviews.
To remove all reviews, call the PdfMarkupAnnotationFacade.ClearReviews() method.
The code sample below adds a review to the annotations from a specific author (the document is opened in the WinForms PDF Viewer):
using DevExpress.Pdf;
using (PdfDocumentProcessor processor = new PdfDocumentProcessor())
{
// Load a document
processor.LoadDocument("..\\..\\Document.pdf");
// Access the first page properties
PdfPageFacade pageFacade = processor.DocumentFacade.Pages[0];
foreach(PdfMarkupAnnotationFacade markupAnnotation in pageFacade.Annotations)
{
// Check the annotation author
if (markupAnnotation.Author == "Brian Zetc")
{
// Add a review to the annotation
markupAnnotation.AddReview("Cardle Anita W", PdfAnnotationReviewStatus.Accepted);
}
}
// Save the result
processor.SaveDocument("..\\..\\Result.pdf");
}
#Flatten Annotations
Call one of the following methods to flatten an annotation:
| Method | Description |
|---|---|
| Pdf |
Flattens document annotations. |
| Pdf |
Flattens annotations of a specific page. |
| Pdf |
Flattens a specific annotation. |
Note
When you call one of the Flatten… methods for redaction annotations, their overlay parameters (text, fill color, and so on) are not applied and redacted content is not removed. Use one of the Apply methods to apply these annotations.
The code sample below flattens all text annotations in the document:
using (PdfDocumentProcessor processor = new PdfDocumentProcessor())
{
// Load a document:
processor.LoadDocument("..\\..\\Document.pdf");
// Flatten all text annotations:
PdfDocumentFacade documentFacade = processor.DocumentFacade;
documentFacade.FlattenAnnotations(PdfAnnotationType.Text);
// Save the result:
processor.SaveDocument("..\\..\\Result.pdf");
}
#Remove Annotations
Call the PdfAnnotationFacade.Remove() method to remove an annotation.
The code sample below removes all annotations from a specific author:
using DevExpress.Pdf;
using System.Linq;
using (PdfDocumentProcessor processor = new PdfDocumentProcessor())
{
// Load a document
processor.LoadDocument("..\\..\\Document.pdf");
// Access the first page properties
PdfPageFacade pageFacade = processor.DocumentFacade.Pages[0];
// Retrieve all markup annotations
var markups = pageFacade.Annotations.Where
(annotation => annotation.Type != PdfAnnotationType.Link).ToList();
foreach(PdfMarkupAnnotationFacade markupAnnotation in markups)
{
// Check the annotation author
if (markupAnnotation.Author == "Brian Zetc")
{
// Remove the annotation
markupAnnotation.Remove();
}
}
// Save the result
processor.SaveDocument("..\\..\\Result.pdf");
}