public void takeScreenshotOfDocument(String documentFileName) {
File documentFile = new File(documentFileName);
File documentDirectory = documentFile.getParentFile();
String imageName = FileUtils.getBaseName(documentFile.getName()) + ".png";
File screenshotFile = new File(documentDirectory, imageName);
NodeBoxDocument doc = NodeBoxDocument.load(documentFile);
addDocument(doc);
doc.setVisible(true);
doc.takeScreenshot(screenshotFile);
doc.close();
}