Annotate on images in C# .NET

Adding annotations to images is possible using XMP annotations with the XML-based syntax. The XMP annotations are handled by the AnnotationManager class. The list below shows all possible XMP annotation types:

  • Text annotation
  • Rubber stamp
  • Geometric — An annotation represented as a geometric figure (line, arrow, ellipse, polygon, and so on).
  • Free hand — A freely drawn line.
  • Comment annotation — An annotation linked to an already existing annotation.
  • Sticky note — A text annotation confined in a colored rectangular area with borders.

To learn more about XMP annotations, refer to the XMP annotations guide.

To add an XMP annotation to an image, use the following steps:

  1. Create an AnnotationManager object.
  2. Load an image to the AnnotationManager object with the InitFromFile method.
  3. Use any method from the AnnotationManager class that starts with Add... to add an XMP annotation. Alternatively, create a new annotation by using the specific annotation class — for example, the AnnotationRubberStamp class.
  4. Optional: Set the XMP annotation’s properties. For more information, refer to the guide covering XMP annotation object properties.
  5. Save the newly created annotation with the SaveAnnotationsToPage method.
  6. Optional: Flatten the XMP annotation into the image with the BurnAnnotationsToPage method. Flattened annotations are no longer editable.
  7. Save the image with the SaveDocumentToJPEG method.

To add a stamp annotation and flatten it into an image, use the following code:

using AnnotationManager annotationManager = new AnnotationManager();
// Load an image to the `AnnotationManager` object.
annotationManager.InitFromFile(@"C:\temp\source.jpg");
// Create a new `AnnotationEllipse` object.
AnnotationRubberStamp annotStamp = annotationManager.AddRubberStampAnnot(GdPictureColor.Blue, 2, 1, 4, 2, "APPROVED");
// Rotate the annotation clockwise by 30 degrees.
annotStamp.Rotation = -30;
// Set the `Author` property of the annotation.
annotStamp.Author = "Nutrient";
// Save the annotation to the image.
annotationManager.SaveAnnotationsToPage();
// Flatten the annotation.
annotationManager.BurnAnnotationsToPage(false);
// Save the image with the annotation to a file.
annotationManager.SaveDocumentToJPEG(@"C:\temp\output.jpg", 75);

Used methods

Related topics