question: public void writeJPEGImage ( File file ) { int width = vv . getWidth ( ) ; int height = vv . getHeight ( ) ; BufferedImage bi = new BufferedImage ( width , height , BufferedImage . TYPE_INT_RGB ) ; Graphics2D graphics = bi . createGraphics ( ) ; vv . paint ( graphics ) ; graphics . dispose ( ) ; try { ImageIO . write ( bi , "jpeg" , file ) ; } catch ( Exception e ) { e . printStackTrace ( ) ; } }
target:  copy the visible part of the graph to a file as a jpeg image