Syncfusion AI Assistant

How can I help you?

Polygon Annotation (Shape) in Angular PDF Viewer

26 Mar 202610 minutes to read

Polygon annotations allow users to outline irregular regions, draw custom shapes, highlight non-rectangular areas, or create specialized callouts on PDFs for review and markup.

Polygon overview

Enable Polygon Annotation in the Viewer

To enable Line annotations, inject the following modules into the Angular PDF Viewer:

import { Component } from '@angular/core';
import {
  PdfViewerModule,
  ToolbarService,
  AnnotationService
} from '@syncfusion/ej2-angular-pdfviewer';

@Component({
  selector: 'app-root',
  template: `
    <div class="content-wrapper">
      <ejs-pdfviewer
        id="pdfViewer"
        [documentPath]="document"
        [resourceUrl]="resource"
        style="height:650px;display:block">
      </ejs-pdfviewer>
    </div>
  `,
  imports: [PdfViewerModule],
  providers: [ToolbarService, AnnotationService]
})
export class AppComponent {

  public document: string =
    'https://cdn.syncfusion.com/content/pdf/pdf-succinctly.pdf';

  public resource: string =
    'https://cdn.syncfusion.com/ej2/31.2.2/dist/ej2-pdfviewer-lib';
}

Add Polygon Annotation

Add Polygon Annotation Using the Toolbar

  1. Open the Annotation Toolbar.
  2. Select Shapes → Polygon.
  3. Click multiple points on the page to draw the polygon.
  4. Double-click to finalize the shape.

Shape toolbar

NOTE

When in Pan mode, selecting a shape tool automatically switches the viewer to selection mode for smooth interaction.

Enable Polygon Mode

Switch the viewer into highlight mode using setAnnotationMode('Polygon').

enablePolygonMode(): void {
  const pdfViewer = (document.getElementById('pdfViewer') as any).ej2_instances[0];
  pdfViewer.annotation.setAnnotationMode('Polygon');
}

Exit Polygon Mode

Switch back to normal mode using:

exitPolygonMode(): void {
  const pdfViewer = (document.getElementById('pdfViewer') as any).ej2_instances[0];
  pdfViewer.annotation.setAnnotationMode('None');
}

Add Polygon Programmatically

Use the addAnnotation API to draw a polygon by specifying multiple vertexPoints.

addPolygon(): void {
  const pdfViewer = (document.getElementById('pdfViewer') as any).ej2_instances[0];

  pdfViewer.annotation.addAnnotation('Polygon', {
    offset: { x: 200, y: 800 },
    pageNumber: 1,
    vertexPoints: [
      { x: 200, y: 800 }, { x: 242, y: 771 },
      { x: 289, y: 799 }, { x: 278, y: 842 },
      { x: 211, y: 842 }, { x: 200, y: 800 }
    ]
  });
}

Customize Polygon Appearance

Configure default polygon appearance (fill color, stroke color, thickness, opacity) using the polygonSettings property.

import { Component } from '@angular/core';
import {
  PdfViewerModule,
  ToolbarService,
  AnnotationService
} from '@syncfusion/ej2-angular-pdfviewer';

@Component({
  selector: 'app-root',
  template: `
    <div class="content-wrapper">
      <ejs-pdfviewer
        id="pdfViewer"
        [documentPath]="document"
        [resourceUrl]="resource"
        [polygonSettings]="polygonSettings"
        style="height:650px;display:block">
      </ejs-pdfviewer>
    </div>
  `,
  imports: [PdfViewerModule],
  providers: [ToolbarService, AnnotationService]
})
export class AppComponent {

  public document: string =
    'https://cdn.syncfusion.com/content/pdf/pdf-succinctly.pdf';

  public resource: string =
    'https://cdn.syncfusion.com/ej2/31.2.2/dist/ej2-pdfviewer-lib';

  public polygonSettings = {
    fillColor: '#ffa5d8',
    strokeColor: '#ff6a00',
    thickness: 2,
    opacity: 0.9
  };
}

Manage Polygon (Edit, Move, Resize, Delete)

Edit Circle

Edit Circle (UI)

  • Select a Circle to view resize handles.
  • Drag any side/corner to resize; drag inside the shape to move it.
  • Edit fill, stroke, thickness, and opacity using the annotation toolbar.

Shape tools

Use the annotation toolbar:

  • Edit fill Color tool
    Edit fill color

  • Edit stroke Color tool
    Edit stroke color

  • Edit Opacity slider
    Edit opacity

  • Edit Thickness slider
    Edit thickness

Edit Polygon Programmatically

Modify an existing Circle programmatically using editAnnotation().

editPolygonProgrammatically(): void {
  const pdfViewer = (document.getElementById('pdfViewer') as any).ej2_instances[0];

  for (const annot of pdfViewer.annotationCollection) {
    if (annot.subject === 'Polygon') {
      annot.strokeColor = '#0000ff';
      annot.thickness = 2;
      annot.fillColor = '#ffff00';
      pdfViewer.annotation.editAnnotation(annot);
      break;
    }
  }
}

Delete Polygon

The PDF Viewer supports deleting existing annotations through the UI and API.
See Delete Annotation for full behavior and workflows.

Comments

Use the Comments panel to add, view, and reply to threaded discussions linked to polygon annotations. It provides a dedicated interface for collaboration and review within the PDF Viewer.

Set properties while adding Individual Annotation

Configure per-annotation appearance while adding a polygon using addAnnotation.

addMultiplePolygons(): void {
  const pdfViewer = (document.getElementById('pdfViewer') as any).ej2_instances[0];

  // Polygon 1
  pdfViewer.annotation.addAnnotation('Polygon', {
    offset: { x: 200, y: 800 },
    pageNumber: 1,
    vertexPoints: [
      { x: 200, y: 800 }, { x: 242, y: 771 },
      { x: 289, y: 799 }, { x: 278, y: 842 },
      { x: 211, y: 842 }, { x: 200, y: 800 }
    ],
    fillColor: '#ffa5d8',
    strokeColor: '#ff6a00',
    thickness: 2,
    opacity: 0.9,
    author: 'User 1'
  });

  // Polygon 2
  pdfViewer.annotation.addAnnotation('Polygon', {
    offset: { x: 360, y: 800 },
    pageNumber: 1,
    vertexPoints: [
      { x: 360, y: 800 }, { x: 410, y: 770 },
      { x: 450, y: 810 }, { x: 430, y: 850 },
      { x: 380, y: 850 }, { x: 360, y: 800 }
    ],
    fillColor: '#ffe600',
    strokeColor: '#ff1010',
    thickness: 3,
    opacity: 0.85,
    author: 'User 2'
  });
}

Disable Shape Annotation

Disable shape annotations (Polygon, Line, Rectangle, Circle, Arrow) using the enableShapeAnnotation property.

import { Component } from '@angular/core';
import {
  PdfViewerModule,
  ToolbarService,
  AnnotationService
} from '@syncfusion/ej2-angular-pdfviewer';

@Component({
  selector: 'app-root',
  template: `
    <div class="content-wrapper">
      <ejs-pdfviewer
        id="pdfViewer"
        [enableShapeAnnotation]="false"
        [documentPath]="document"
        [resourceUrl]="resource"
        style="height:650px;display:block">
      </ejs-pdfviewer>
    </div>
  `,
  imports: [PdfViewerModule],
  providers: [ToolbarService, AnnotationService]
})
export class AppComponent {

  public document: string =
    'https://cdn.syncfusion.com/content/pdf/pdf-succinctly.pdf';

  public resource: string =
    'https://cdn.syncfusion.com/ej2/31.2.2/dist/ej2-pdfviewer-lib';
}

Handle Polygon Events

The PDF viewer provides annotation life-cycle events that notify when Polygon annotations are added, modified, selected, or removed.
For the full list of available events and their descriptions, see Annotation Events

Export and Import

The PDF Viewer supports exporting and importing annotations. For details on supported formats and workflows, see Export and Import annotations.

See Also