The Annotation Editor in GcDocs PDF Viewer allows you to edit and review PDF documents. You can add or remove different types of annotations, comment or reply on comments and set or modify annotation properties like text, color, position, border, style etc. All the annotations in a document are listed in the Property panel so that any annotation can be accessed and modified at any point of time.

The below image shows Annotation editor in GcDocs PDF Viewer with a PDF document containing a Text annotation.

The different toolbar buttons are described as below. To know more about different annotations, refer Annotation Types.

Toolbar Icons	Description
	Select an annotation added on PDF
	Adds text or sticky notes on the PDF
	Adds a note that is always visible on the PDF
	Draws free-hand scribble on the PDF
	Adds a rectangle shape on PDF
	Adds a circle shape on the PDF
	Adds a straight line on the PDF
	Adds closed or open shapes of multiple edges on the PDF
	Adds a polygon on the PDF
	Attaches a file to the document, which will be embedded in the PDF
	Adds sound (.au, .aiff, or .wav format) imported from a file or recorded from the computer’s microphone
	Deletes the annotation
	Marks region on PDF document to be redacted
	Applies redact to all regions marked for redact

Apart from the different types of annotations described above, GcDocs PDF Viewer also provides some general editing features while working with PDF documents. They are explained as below:

Toolbar Icons	Description
	Undo changes
	Redo changes
	Saves the modified document on client
	Creates a new blank document
	Inserts a blank page
	Deletes current page

Property Panel of Annotation Editor

When you click the Annotation editor icon in the left vertical panel, the Property panel of the Annotation editor becomes visible. The Property panel displays the list of all the annotations page-wise in your document.

It also allows you to set or modify properties of any annotation in the document like its text, color, border location etc. For eg. The image below shows the properties of a square annotation in the Property panel.

Redact Annotation

The annotation editor allows you to add Redact annotation. A redact annotation marks an area under which all the existing content should be removed from PDF document. Redact annotation, unlike other annotations, is applied in two phases:

  Redact (erase) a region: It highlights the area under which the content needs to be redacted or removed.

  Apply all Redacts: It applies redaction, that is, removes all the content which is marked for redaction.

The below image shows the area marked for redaction in a PDF document. The properties in 'Redaction Mark' can be defined to specify how the highlighted area marked for redaction should look before the redaction has been applied.

After the redaction is applied, the content marked for redaction is removed. However, you can revert the redaction and view the original content by selecting the 'Reset redact' button from the Properties panel.

You can also define the 'Overlay text' or 'Fill Color' in the 'Redacted area' settings whose text or Fill color will appear in place of the redacted content.

When a PDF document with applied redact annotations is saved, the annotations and the content does not exist in the document anymore. They are replaced with the 'Redacted Area' properties. Also, as the content is removed, the redacted area cannot be used to copy or paste the content under redaction into other documents.

Enable Annotation Editor in GcDocs PDF Viewer

The Annotation editor is displayed by default in GcDocs PDF Viewer, by enabling the AnnotationEditorPanel in the viewer using code:

<script>
    var viewer = new GcPdfViewer("#host", { supportApi: 'SupportApi/GcPdfViewer' });
    viewer.addDefaultPanels();
    viewer.addAnnotationEditorPanel();
    viewer.beforeUnloadConfirmation = true;
    viewer.open("Home/GetPdf");
</script>

To customize the annotation options in GcDocs PDF Viewer, add the following lines of code in the class file where you load the PDF in the Viewer:

public static GcPdfViewerSupportApiDemo.Models.PdfViewerOptions PdfViewerOptions
{
        get => new GcPdfViewerSupportApiDemo.Models.PdfViewerOptions(
        GcPdfViewerSupportApiDemo.Models.PdfViewerOptions.Options.AnnotationEditorPanel |
        GcPdfViewerSupportApiDemo.Models.PdfViewerOptions.Options.ActivateAnnotationEditor,
        annotationEditorTools: new string[] { "edit-select", "$split", "edit-text", "edit-free-text", "$split", "edit-erase", "$split", "edit-redact", "edit-redact-apply", "$split", "edit-undo", "edit-redo", "save" });
}

Review PDF document using Annotation editor

Follow the below steps to review a PDF document using the annotation editor in GcDocs PDF Viewer:

1. Configure the GcDocs PDF Viewer for editing PDF documents.
2. Run the application and open the PDF you want to review using the Open button.
3. Open the Annotation Editor using the second last icon on the left vertical toolbar.
4. Choose any annotation from the different annotations available in the toolbar at the top.
5. Use that annotation to mark a correction in your document.
6. Set annotation properties from the Property panel like color, border etc.
7. Add a Text annotation and type the final review text.
8. Close the Annotation editor and go back to View mode.

The annotations are successfully added annotations to the document. You can also view the list of all the annotations in the property panel of Annotation Editor.