oldcodeannotation.cs

// Creating annotation list
List<AnnotationInfo> annotations = new List<AnnotationInfo>()
{
    new AnnotationInfo()
    {
        PageNumber = 0,
        Box = new Rectangle(100, 100, 100, 100),
        Type = Domain.AnnotationType.Area,
        Text = "area"
    },
                 
    new AnnotationInfo()
    {
        PageNumber = 0,
        Box = new Rectangle(200, 200, 80, 80),
        Type = Domain.AnnotationType.Ellipse,
        Text = "ellipse"
    }
};
 
// Create annotation config
AnnotationConfig config = new AnnotationConfig();
// Set storage path
config.StoragePath = "storage";
// Create annotation handler
AnnotationImageHandler annotator = new AnnotationImageHandler(config);
// Create input file
using (FileStream fs = new FileStream("input.pdf", FileMode.Open))
{
    // Export annotations and save result
    Stream result = annotator.ExportAnnotationsToDocument(fs, annotations);
}