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// For complete examples and data files, please go to https://github.com/groupdocs-annotation/GroupDocs.Annotation-for-.NET
// Create instance of annotator. 
AnnotationConfig cfg = CommonUtilities.GetConfiguration();

//Create annotation handler
AnnotationImageHandler annotator = new AnnotationImageHandler(cfg);

IUserDataHandler userRepository = annotator.GetUserDataHandler();

IDocumentDataHandler documentRepository = annotator.GetDocumentDataHandler();
if (!Directory.Exists(cfg.StoragePath))
{
    Directory.CreateDirectory(cfg.StoragePath);
}

// Create owner. 
var johnOwner = userRepository.GetUserByEmail("john@doe.com");
if (johnOwner == null)
{
    userRepository.Add(new User { FirstName = "John", LastName = "Doe", Email = "john@doe.com" });
    johnOwner = userRepository.GetUserByEmail("john@doe.com");
}

// Create document data object in storage
var document = documentRepository.GetDocument("Document.pdf");
long documentId = document != null ? document.Id : annotator.CreateDocument("Document.pdf", DocumentType.Pdf, johnOwner.Id);

// Create reviewer. 
var reviewerInfo = new ReviewerInfo
{
    PrimaryEmail = "judy@doe.com",
    FirstName = "Judy",
    LastName = "Doe",

    // Can only get view annotations
    AccessRights = AnnotationReviewerRights.CanView
};

// Add collaboorator to the document. If user with Email equals to reviewers PrimaryEmail is absent it will be created.
var addCollaboratorResult = annotator.AddCollaborator(documentId, reviewerInfo);

// Get document collaborators
var getCollaboratorsResult = annotator.GetCollaborators(documentId);
var judy = userRepository.GetUserByEmail("judy@doe.com");

// Create annotation object
AnnotationInfo pointAnnotation = new AnnotationInfo
{
    AnnotationPosition = new Point(852.0, 81.0),
    Box = new Rectangle(212f, 81f, 142f, 0.0f),
    Type = AnnotationType.Point,
    PageNumber = 0,
    CreatorName = "Anonym A."
};

// John try to add annotations. User is owner of the document.
var johnResult = annotator.CreateAnnotation(pointAnnotation, documentId, johnOwner.Id);

// Judy try to add annotations
try
{
    var judyResult = annotator.CreateAnnotation(pointAnnotation, documentId, judy.Id);
}

 //Get exceptions, because user can only view annotations
catch (AnnotatorException e)
{
    Console.Write(e.Message);
    Console.ReadKey();
}

// Allow Judy create annotations.
reviewerInfo.AccessRights = AnnotationReviewerRights.CanAnnotate;
var updateCollaboratorResult = annotator.UpdateCollaborator(documentId, reviewerInfo);

// Now user can add annotations
var judyResultCanAnnotate = annotator.CreateAnnotation(pointAnnotation, documentId, judy.Id);