Get Started

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Learn more

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Common use cases

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Open a document

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Save a document

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Viewer

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UI Customization

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Annotations

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Collaboration

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Forms

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Signature

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Measurement

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PDF.js Express REST API

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Create measurement annotations

Create measurement annotations with the UI

To create measurement annotations in PDF.js Express Web Viewer, click on the measurement tool icon, select one of the tools. Next click and drag on the document to create a measurement annotation. An overlay with measurement information will show up when you are creating or selecting a measurement annotation.

Creating Measurement Annotations

Get scale and precision programmatically

The following example shows how you can determine if an annotation is a measurement annotation and logs the precision and scale of it after it's added:

WebViewer(...)
  .then(instance => {
    const { docViewer, annotManager } = instance;

    annotManager.on('annotationChanged', (annotations, action) => {
      if (action === 'add') {
        // An annotation is an measurement annotation if it contains a Measure property
        const measurementAnnotations = annotations.filter(annotation => annotation.Measure);

        measurementAnnotations.forEach(annotation => {
          console.log(annotation.Scale);
          console.log(annotation.Precision);
        });
      }
    });
  });