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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Annotation History

The Annotation History Manger keeps track of changes the user has recently made to any annotations. It contains APIs to undo and redo these changes.

To get a reference to the history manager, use the docViewer.getAnnotationHistoryManager() API. From there, you can can call functions such as undo() and redo().

For example, to make your own custom button that undoes the last change to an annotation, you could do something like this:

WebViewer({...}, ele)
  .then(instance => {

    const { docViewer } = instance;

    docViewer.on('annotationsLoaded', () => {
      const historyManager = docViewer.getAnnotationHistoryManager();

      document.getElementById('undo-button').onclick = () => {
        if(historyManager.canUndo()) {
          historyManager.undo();
        }
      }
    })

  })