Customize Annotations in JavaScript (ES6) PDF Viewer

21 Oct 202615 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] (./annotation-types/highlight-annotation/#set-default-properties-during-control-initialization)
• Strikethrough: Use [strikethroughSettings] (./annotation-types/strikethrough-annotation/#default-strikethrough-settings-during-initialization)
• Underline: Use [underlineSettings] (./annotation-types/underline-annotation/#default-underline-settings-during-initialization)
• Squiggly: Use [squigglySettings] (./annotation-types/Squiggly-annotation/#set-default-properties-during-control-initialization)

Shape annotations:

• Line: Use [lineSettings] (./annotation-types/line-annotation/#default-line-settings-during-initialization)
• Arrow: Use [arrowSettings] (./annotation-types/arrow-annotation/#default-arrow-settings-during-initialization)
• Rectangle: Use [rectangleSettings] (./annotation-types/rectangle-annotation/#default-rectangle-settings-during-initialization)
• Circle: Use [circleSettings] (./annotation-types/circle-annotation/#default-circle-settings-during-initialization)
• Polygon: Use [polygonSettings] (./annotation-types/polygon-annotation/#default-polygon-settings-during-initialization)
• Cloud: Use [cloudSettings] (./annotation-types/cloud-annotation/#configure-default-cloud-annotation-settings)

Measurement annotations:

• Distance: Use [distanceSettings] (./annotation-types/distance-annotation/#default-distance-settings-during-initialization)
• Perimeter: Use [perimeterSettings] (./annotation-types/perimeter-annotation/#default-perimeter-settings-during-initialization)
• Area: Use [areaSettings] (./annotation-types/area-annotation/#default-area-settings-during-initialization)
• Radius: Use [radiusSettings] (./annotation-types/radius-annotation/#default-radius-settings-during-initialization)
• Volume: Use [volumeSettings] (./annotation-types/volume-annotation/#default-volume-settings-during-initialization)

Other Annotations:

• Redaction: Use [redactionSettings] (./annotation-types/redaction-annotation/#default-redaction-settings-during-initialization)
• Free text: Use [freeTextSettings] (./annotation-types/free-text-annotation/#default-free-text-settings-during-initialization)
• Ink (freehand): Use [inkAnnotationSettings] (./annotation-types/ink-annotation/#default-ink-settings-during-initialization)
• Stamp: Use [stampSettings] (./annotation-types/stamp-annotation/#default-stamp-settings-during-initialization)
• Sticky notes: Use [stickyNotesSettings] (./annotation-types/sticky-notes-annotation/#default-sticky-notes-settings-during-initialization)

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

Standalone

import { PdfViewer, Toolbar, Magnification, Navigation, LinkAnnotation, ThumbnailView, BookmarkView, TextSelection, Annotation, FormDesigner, FormFields } from '@syncfusion/ej2-pdfviewer';

PdfViewer.Inject(Toolbar, Magnification, Navigation, LinkAnnotation, ThumbnailView, BookmarkView, TextSelection, Annotation, FormDesigner, FormFields);

const pdfviewer: PdfViewer = new PdfViewer({
  documentPath: 'https://cdn.syncfusion.com/content/pdf/pdf-succinctly.pdf',
  resourceUrl: "https://cdn.syncfusion.com/ej2/31.1.23/dist/ej2-pdfviewer-lib",
  // 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 }
});

pdfviewer.appendTo('#PdfViewer');

Server-Backed

import { PdfViewer, Toolbar, Magnification, Navigation, LinkAnnotation, ThumbnailView, BookmarkView, TextSelection, Annotation } from '@syncfusion/ej2-pdfviewer';

PdfViewer.Inject(Toolbar, Magnification, Navigation, LinkAnnotation, ThumbnailView, BookmarkView, TextSelection, Annotation);

const pdfviewer: PdfViewer = new PdfViewer({
  documentPath: 'https://cdn.syncfusion.com/content/pdf/pdf-succinctly.pdf',

  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 },

  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 },

  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' },

  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 }
});

pdfviewer.serviceUrl = 'https://document.syncfusion.com/web-services/pdf-viewer/api/pdfviewer/';
pdfviewer.appendTo('#PdfViewer');

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.

<button id="bulkUpdateAnn">Bulk update annotations</button>

// Requires a PdfViewer instance named `pdfviewer`
document.getElementById('bulkUpdateAnn')?.addEventListener('click', () => {
  for (let i = 0; i < pdfviewer.annotationCollection.length; i++) {
    const ann = pdfviewer.annotationCollection[i];
    // 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;
      pdfviewer.annotation.editAnnotation(ann);
    }
  }
});

Customize Annotation Settings

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

<div id="PdfViewer" style="height: 100%;width: 100%;"></div>

import { PdfViewer, Toolbar, Magnification, Navigation, LinkAnnotation, ThumbnailView, BookmarkView,
    TextSelection, TextSearch, Print, Annotation, FormFields, FormDesigner } from '@syncfusion/ej2-pdfviewer';

    PdfViewer.Inject(Toolbar,Magnification,Navigation, LinkAnnotation,ThumbnailView,BookmarkView,
    TextSelection, TextSearch, Print, Annotation,FormFields, FormDesigner);

    let viewer: PdfViewer = new PdfViewer();
    viewer.resourceUrl = "https://cdn.syncfusion.com/ej2/31.1.23/dist/ej2-pdfviewer-lib";
    viewer.documentPath = "PDF_Succinctly.pdf";
    // Change the annotation settings.
    viewer.annotationSettings = {
         author: 'XYZ', 
         minHeight: 10, 
         minWidth: 10, 
         maxWidth: 100, 
         maxHeight: 100, 
         isLock: false, 
         skipPrint: false, 
         skipDownload: false, 
         allowedInteractions: [AllowedInteraction.Select, AllowedInteraction.Move] 
        };
    viewer.appendTo('#PdfViewer');

Customize Annotation SelectorSettings

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

<div id="PdfViewer" style="height: 100%;width: 100%;"></div>

import { PdfViewer, Toolbar, Magnification, Navigation, LinkAnnotation, ThumbnailView, BookmarkView,
    TextSelection, TextSearch, Print, Annotation, FormFields, FormDesigner, AnnotationResizerLocation, CursorType } from '@syncfusion/ej2-pdfviewer';

    PdfViewer.Inject(Toolbar,Magnification,Navigation, LinkAnnotation,ThumbnailView,BookmarkView,
    TextSelection, TextSearch, Print, Annotation,FormFields,FormDesigner);

    let viewer: PdfViewer = new PdfViewer();
    viewer.resourceUrl = "https://cdn.syncfusion.com/ej2/31.1.23/dist/ej2-pdfviewer-lib";
    viewer.documentPath = "PDF_Succinctly.pdf";
    // Change the annotation selector settings.
    viewer.annotationSelectorSettings = {
         selectionBorderColor: 'blue', 
         resizerBorderColor: 'red', 
         resizerFillColor: '#4070ff', 
         resizerSize: 8, 
         selectionBorderThickness: 1, 
         resizerShape: 'Circle', 
         selectorLineDashArray: [5, 6], 
         resizerLocation: AnnotationResizerLocation.Corners | AnnotationResizerLocation.Edges, 
         resizerCursorType: CursorType.grab 
        };
    viewer.appendTo('#PdfViewer');

View Sample on GitHub

See also

• Annotation Overview
• Annotation Types
• Annotation Toolbar
• Create and Modify Annotation
• Remove Annotation
• Handwritten Signature
• Export and Import Annotation
• Annotation Permission
• Annotation in Mobile View
• Annotation Events
• Annotation API