Setting up measurements in WebViewer

When creating a new instance of WebViewer, the enableMeasurement property needs to be set to true to display the measurement annotation tools in the UI

WebViewer({
  ... // other options
  enableMeasurement: true
}, viewerElement);

Besides passing in a constructor option, measurement can be toggled using the WebViewer API with the enableFeatures and disableFeatures functions.

WebViewer({
  ... // other options
}, viewerElement)
  .then(instance => {
    instance.UI.enableFeatures([instance.Feature.Measurement]);
  });