Annotations overview in Blazor SfPdfViewer

17 Jul 20261 minute to read

Annotations in the SfPdfViewer are interactive elements that allow users to add notes, highlights, or text boxes directly to a PDF document. They add context and feedback to PDFs, simplifying collaboration during document reviews.

The Blazor SfPdfViewer provides a complete set of annotation tools for reviewing, measuring, and marking up PDFs.

Supported annotations

Annotation manipulation capabilities

  • Create annotations: Use the toolbar, context menu, or APIs to add highlights, notes, shapes, and more directly onto the PDF document.
  • Edit annotations: Modify existing annotations by moving, resizing, or updating text and style properties like color, opacity, and thickness.
  • Delete annotations: Remove unwanted annotations using the context menu or the DeleteAnnotationAsync API.
  • Customize annotations: Adjust appearance and behavior—such as fonts, fill colors, and opacity—through the UI or configuration options.
  • Undo and redo annotations: Revert or reapply annotation actions (add, edit, delete) using toolbar buttons or corresponding APIs.
  • Import and export annotations: Save and load annotations in JSON (.json) or XFDF (.xfdf) formats to persist markups across sessions or share them with others.
  • Set permissions: Enable or disable the AnnotationPermission enum value (default: AnnotationPermission.All) to control which annotation actions users can perform.
  • Add and manage comments: Insert, edit, and delete comments or sticky notes attached to annotations for clearer feedback and collaboration. The Comments pane must be enabled in the toolbar settings.

See also