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.
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);
});
}
});
});
WebViewer(...)
.then(instance => {
const { annotationManager } = instance.Core;
annotationManager.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);
});
}
});
});
