* Updates the thumbnail component rendering transform.
*/
protected void updateThumbnailRenderingTransform() {
SVGDocument svgDocument = svgCanvas.getSVGDocument();
if (svgDocument != null) {
SVGSVGElement elt = svgDocument.getRootElement();
Dimension dim = svgThumbnailCanvas.getSize();
String viewBox = elt.getAttributeNS
(null, SVGConstants.SVG_VIEW_BOX_ATTRIBUTE);
AffineTransform Tx;
if (viewBox.length() != 0) {
String aspectRatio = elt.getAttributeNS
(null, SVGConstants.SVG_PRESERVE_ASPECT_RATIO_ATTRIBUTE);
Tx = ViewBox.getPreserveAspectRatioTransform
(elt, viewBox, aspectRatio, dim.width, dim.height);
}else {
// no viewBox has been specified, create a scale transform