Getting text from text select events

The main event of interest triggered by DocumentViewer when text is selected is the textSelected event.

WebViewer({ ... }, viewerElement).then(instance => {
  const { documentViewer } = instance.Core;

  documentViewer.addEventListener('textSelected', (quads, selectedText, pageNumber) => {
    // quads will be an array of 'Quad' objects
    // text is the selected text as a string
    if (selectedText.length > 0) {
      console.log(selectedText);
    }
  });
});

The textSelected event gets fired whenever the selected text on the document changes. It is worth considering using debouncing if you are only looking to handle this event once the selection has stopped.

Also the textSelected event fires once for each page with selected text. So if text is selected on page A and B, and the selected text on page A changed, the textSelected event will fire once for each page even though there weren't any changes for page B.

You can also listen for the selectionComplete event on the TextSelect tool. This event does not return the selected text but we can still get the text from the DocumentViewer via getSelectedText.

WebViewer({ ... }, viewerElement).then(instance => {
  const { documentViewer, Tools } = instance.Core;

  const tool = documentViewer.getTool(Tools.ToolNames.TEXT_SELECT);
  tool.addEventListener('selectionComplete', (startQuad, allQuads) => {
    let selectedText = '';
    Object.keys(allQuads).forEach(pageNum => {
      const text = documentViewer.getSelectedText(pageNum);
      selectedText += text;
    });
    // the startQuad and allQuads will have the X and Y values you want
  });
});

Get selected text by listening for a keydown or clipboard copy event.

WebViewer({ ... }, viewerElement).then(instance => {
  const { documentViewer } = instance.Core;
  const showSelectedText = () => {
    const page = documentViewer.getCurrentPage();
    const text = documentViewer.getSelectedText(page);

    if (!!text) {
        console.log(text);
    }
  }

  // Optionally use keyDown events
  documentViewer.addEventListener('keyDown', function (e) {
    if (e.keyCode == 67 && (e.ctrlKey || e.metaKey)) {
      showSelectedText();
      console.log('Ctrl+C pressed');
    }
  });

  // Otherwise use the copy event
  const iframeWindow = instance.UI.iframeWindow;
  iframeWindow.addEventListener('copy', function (e) {
      showSelectedText();
      console.log('Ctrl+C (copy) pressed');
  });
});