svgCanvas.addGVTTreeRendererListener(new ThumbnailGVTListener());
svgCanvas.addSVGDocumentLoaderListener(new ThumbnailDocumentListener());
svgCanvas.addComponentListener(new ThumbnailCanvasComponentListener());
// create the thumbnail
svgThumbnailCanvas = new JGVTComponent();
overlay = new AreaOfInterestOverlay();
svgThumbnailCanvas.getOverlays().add(overlay);
svgThumbnailCanvas.setPreferredSize(new Dimension(150, 150));
svgThumbnailCanvas.addComponentListener(new ThumbnailComponentListener());
aoiListener = new AreaOfInterestListener();