Customize Annotations in React PDF Viewer

21 Oct 202614 minutes to read

Annotation appearance and behavior (for example color, stroke color, thickness, and opacity) can be customized using the built‑in UI or programmatically. This page summarizes common customization patterns and shows how to set defaults per annotation type.

Customize via UI

Use the annotation toolbar after selecting an annotation:

Edit color: changes the annotation fill/text color
Edit stroke color: changes border or line color for shapes and line types.
Edit thickness: adjusts border or line thickness
Edit opacity: adjusts transparency

The annotation toolbar also exposes Border Style options (Solid, Cloud, Dashed) on shape and measurement annotations that support additional border styles. See Cloud Annotation for cloud-specific appearance options and the per-annotation pages linked below for border-style customization.

Type‑specific options (for example, Line properties) are available from the context menu (right‑click > Properties) where supported.

Border Style Support Matrix

Use this matrix to find which annotation types support the Solid, Cloud, and Dashed border styles and the settings property that controls them.

Annotation Type	Solid	Cloud	Dashed	Settings property
Rectangle	✓	✓	✓	`rectangleSettings`
Circle	✓	✓	✓	`circleSettings`
Polygon	✓	✓	✓	`polygonSettings`
Cloud	✓	✓	—	`cloudSettings`
Free Text	✓	✓	✓	`freeTextSettings`
Area	✓	✓	✓	`areaSettings`
Radius	✓	✓	✓	`radiusSettings`
Volume	✓	✓	✓	`volumeSettings`
Perimeter	✓	—	✓	`perimeterSettings`
Distance	✓	—	✓	`distanceSettings`
Line	✓	—	✓	`lineSettings`
Arrow	✓	—	✓	`arrowSettings`

Use the BorderStyle enum together with the optional borderDashArray (Dashed) and cloudIntensity (Cloud) settings. cloudIntensity accepts values from 1 to 2; the default value is 1.

Set default properties during initialization

Set defaults for specific annotation types when creating the PdfViewer instance. Configure properties such as author, subject, color, and opacity using annotation settings. The examples below reference settings used on the annotation type pages.

Text markup annotations:

Highlight: Set default properties before creating the control using highlightSettings
Strikethrough: Use strikethroughSettings
Underline: Use underlineSettings
Squiggly: Use squigglySettings

Shape annotations:

Line: Use lineSettings
Arrow: Use arrowSettings
Rectangle: Use rectangleSettings
Circle: Use circleSettings
Polygon: Use polygonSettings
Cloud: Use cloudSettings

Measurement annotations:

Distance: Use distanceSettings
Perimeter: Use perimeterSettings
Area: Use areaSettings
Radius: Use radiusSettings
Volume: Use volumeSettings

Other Annotations:

Redaction: Use redactionSettings
Free text: Use freeTextSettings
Ink (freehand): Use inkAnnotationSettings
Stamp: Use stampSettings
Sticky notes: Use stickyNotesSettings

Set defaults for specific annotation types when creating the PdfViewerComponent. Below are examples using settings already used in the annotation type pages.

Standalone
import * as React from 'react';
import * as ReactDOM from 'react-dom/client';
import {
  PdfViewerComponent, Inject,
  Toolbar, Annotation, TextSelection
} from '@syncfusion/ej2-react-pdfviewer';

function App() {
  return (
    <PdfViewerComponent
      id="container"
      documentPath="https://cdn.syncfusion.com/content/pdf/pdf-succinctly.pdf"
      resourceUrl="https://cdn.syncfusion.com/ej2/31.2.2/dist/ej2-pdfviewer-lib"
      style={{ height: '650px' }}

      // Text markup defaults
      highlightSettings={{ author: 'QA', subject: 'Review', color: '#ffff00', opacity: 0.6 }}
      strikethroughSettings={{ author: 'QA', subject: 'Remove', color: '#ff0000', opacity: 0.6 }}
      underlineSettings={{ author: 'Guest User', subject: 'Points to be remembered', color: '#00ffff', opacity: 0.9 }}
      squigglySettings={{ author: 'Guest User', subject: 'Corrections', color: '#00ff00', opacity: 0.9 }}

      // Shapes
      lineSettings={{ strokeColor: '#0066ff', thickness: 2, opacity: 0.8 }}
      arrowSettings={{ strokeColor: '#0066ff', thickness: 2, opacity: 0.8 }}
      rectangleSettings={{ fillColor: '#ffffff00', strokeColor: '#222222', thickness: 1, opacity: 1 }}
      circleSettings={{ fillColor: '#ffffff00', strokeColor: '#222222', thickness: 1, opacity: 1 }}
      polygonSettings={{ fillColor: '#ffffff00', strokeColor: '#222222', thickness: 1, opacity: 1 }}

      // Measurements
      distanceSettings={{ strokeColor: '#0066ff', thickness: 2, opacity: 0.8 }}
      perimeterSettings={{ strokeColor: '#0066ff', thickness: 2, opacity: 0.8 }}
      areaSettings={{ strokeColor: '#0066ff', thickness: 2, opacity: 0.8, fillColor: '#ffffff00' }}
      radiusSettings={{ strokeColor: '#0066ff', thickness: 2, opacity: 0.8, fillColor: '#ffffff00' }}
      volumeSettings={{ strokeColor: '#0066ff', thickness: 2, opacity: 0.8, fillColor: '#ffffff00' }}

      // Others
      freeTextSettings={{ borderColor: '#222222', thickness: 1, opacity: 1 }}
      inkAnnotationSettings={{ color: '#0000ff', thickness: 3, opacity: 0.8 }}
      stampSettings={{ opacity: 0.9 }}
      stickyNotesSettings={{ author: 'QA', subject: 'Review', color: '#ffcc00', opacity: 1 }}
    >
      <Inject services={[Toolbar, Annotation, TextSelection]} />
    </PdfViewerComponent>
  );
}

ReactDOM.createRoot(document.getElementById('sample')).render(<App />);

After changing defaults using UI tools (for example, Edit color or Edit opacity), the updated values apply to subsequent annotations within the same session.

Customize programmatically at runtime

To update an existing annotation from code, modify its properties and call editAnnotation.

Example: bulk‑update matching annotations.

Standalone
import * as React from 'react';
import * as ReactDOM from 'react-dom/client';
import { PdfViewerComponent, Inject, Toolbar, Annotation, TextSelection } from '@syncfusion/ej2-react-pdfviewer';

function getViewer() { return document.getElementById('container').ej2_instances[0]; }

function bulkUpdateAnnotations() {
  const viewer = getViewer();
  for (const ann of viewer.annotationCollection) {
    // Example criteria; customize as needed
    if (ann.author === 'Guest' || ann.subject === 'Rectangle') {
      ann.color = '#ff0000';
      ann.opacity = 0.8;
      // For shapes/lines you can also change strokeColor/thickness when applicable
      // ann.strokeColor = '#222222';
      // ann.thickness = 2;
      viewer.annotation.editAnnotation(ann);
    }
  }
}

function App() {
  return (
    <>
      <button onClick={bulkUpdateAnnotations}>Bulk Update Annotations</button>
      <PdfViewerComponent
        id="container"
        documentPath="https://cdn.syncfusion.com/content/pdf/pdf-succinctly.pdf"
        resourceUrl="https://cdn.syncfusion.com/ej2/31.2.2/dist/ej2-pdfviewer-lib"
        style={{ height: '650px' }}
      >
        <Inject services={[Toolbar, Annotation, TextSelection]} />
      </PdfViewerComponent>
    </>
  );
}

ReactDOM.createRoot(document.getElementById('sample')).render(<App />);

Customize Annotation Settings

Defines the settings of the annotations. You can change annotation settings like author name, height, width etc., using the annotationSettings prop.

Standalone
import * as React from 'react';
import * as ReactDOM from 'react-dom/client';
import {
  PdfViewerComponent, Inject,
  Toolbar, Annotation, TextSelection,
  AllowedInteraction
} from '@syncfusion/ej2-react-pdfviewer';

function App() {
  return (
    <PdfViewerComponent
      id="container"
      documentPath="https://cdn.syncfusion.com/content/pdf/pdf-succinctly.pdf"
      resourceUrl="https://cdn.syncfusion.com/ej2/31.2.2/dist/ej2-pdfviewer-lib"
      style={{ height: '650px' }}
      annotationSettings={{
        author: 'XYZ',
        minHeight: 10,
        minWidth: 10,
        maxWidth: 100,
        maxHeight: 100,
        isLock: false,
        skipPrint: false,
        skipDownload: false,
        allowedInteractions: [AllowedInteraction.Select, AllowedInteraction.Move]
      }}
    >
      <Inject services={[Toolbar, Annotation, TextSelection]} />
    </PdfViewerComponent>
  );
}

ReactDOM.createRoot(document.getElementById('sample')).render(<App />);

Customize Annotation SelectorSettings

Defines the settings of annotation selector. You can customize the annotation selector using the annotationSelectorSettings prop.

Standalone
import * as React from 'react';
import * as ReactDOM from 'react-dom/client';
import {
  PdfViewerComponent, Inject,
  Toolbar, Annotation, TextSelection,
  AnnotationResizerLocation, CursorType
} from '@syncfusion/ej2-react-pdfviewer';

function App() {
  return (
    <PdfViewerComponent
      id="container"
      documentPath="https://cdn.syncfusion.com/content/pdf/pdf-succinctly.pdf"
      resourceUrl="https://cdn.syncfusion.com/ej2/31.2.2/dist/ej2-pdfviewer-lib"
      style={{ height: '650px' }}
      annotationSelectorSettings={{
        selectionBorderColor: 'blue',
        resizerBorderColor: 'red',
        resizerFillColor: '#4070ff',
        resizerSize: 8,
        selectionBorderThickness: 1,
        resizerShape: 'Circle',
        selectorLineDashArray: [5, 6],
        resizerLocation: AnnotationResizerLocation.Corners | AnnotationResizerLocation.Edges,
        resizerCursorType: CursorType.grab
      }}
    >
      <Inject services={[Toolbar, Annotation, TextSelection]} />
    </PdfViewerComponent>
  );
}

ReactDOM.createRoot(document.getElementById('sample')).render(<App />);

View Sample on GitHub

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