text: // locate zoom buttons
  import IconButton from '@material-ui/core/IconButton';
  import { pure } from 'recompose';
  import FullscreenExitIcon from '@material-ui/icons/FullscreenExit';
  import FullscreenIcon from '@material-ui/icons/Fullscreen';
  
  import React from 'react';
  
  const FullscreenButton = function({isVisible, isFullscreen, enableFullscreen, disableFullscreen}) {
    if (!isVisible) {
      return null;
    }
    return <div className="fullscreen-button">
          { isFullscreen ?
          <IconButton onClick={disableFullscreen} title="Exit fullscreen">
            <FullscreenExitIcon />
          </IconButton>
            :
          <IconButton onClick={enableFullscreen} title="Enter fullscreen">
            <FullscreenIcon />
          </IconButton>
          }
    </div>
  }
  export default pure(FullscreenButton);
  