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Redaction UI interactions in Blazor PDF Viewer

12 Feb 20262 minutes to read

Add redaction annotations from the toolbar

Use the redaction tool on the toolbar to draw over content to be redacted. After marking, an annotation can display overlay text (for example, “Confidential”) and be styled with fill color and other properties.

Drawing a redaction annotation on the page

Interactive redaction annotations

  • Movable: Reposition an annotation within the same page.

Moving a redaction annotation

  • Resizable: Adjust the size to cover the required region.

Resizing a redaction annotation

NOTE

The redaction tool is hidden by default. Customize the toolbar to include it. For instructions, see Toolbar customization.

Update redaction properties

Update redaction annotations after they are added. Changes can be made using the property panel for the selected redaction or programmatically via the EditAnnotationAsync API.

Using the property panel

When a redaction annotation is selected, update properties such as overlay text, font, and fill color in the property panel. Changes appear immediately in the viewer.

Access the panel by:

  • Clicking the redaction panel icon on the redaction toolbar.

Redaction Property Panel Icon

  • Using the context menu (right-click or long-press on mobile) and choosing Properties.

Redaction Property Panel via Context Menu

Delete redaction annotations

Delete redaction annotations using any of the following:

  • Right-click and select Delete from the context menu.

Context menu showing Delete for a redaction

  • Click the Delete button on the toolbar.

Toolbar delete icon for redaction

  • Press the Delete key after selecting the annotation.

Redact pages using the UI

Use the Redact Pages option on the redaction toolbar to mark whole pages. The Mark Page Range dialog offers:

  • Current Page – Redacts the currently visible page.
  • Odd Pages Only – Redacts all odd-numbered pages.
  • Even Pages Only – Redacts all even-numbered pages.
  • Specific Pages – Enter a list or ranges (for example, 1, 3–5, 7).

After choosing a range, select Save to apply redaction marks to the selected pages.

Page Redaction Panel

Apply redaction from the toolbar

The redact button applies all redaction annotations in the document.

  • The button is disabled when no redaction annotations exist.
  • It enables automatically when redaction annotations are present.

Redact Button Icon

A confirmation dialog appears before applying redactions to confirm the operation is permanent and irreversible.

Apply Redaction Dialog

NOTE

The redaction process is irreversible. Once applied, the original content cannot be recovered.

See also