Java JfreeChart - how to make zooming in it is less?

Question

The embedded function of zoomInBoth in Jfreechart too strongly zooming in. Whether it is possible to reduce an zooming level? I make my own JButton zoomIn

static ChartPanel chartPanel;
zoomIn.addActionListener(new ActionListener() {
        @Override
        public void actionPerformed(ActionEvent ae) {
            chartPanel.zoomInBoth(E, E);
    });

Edit of numbers in zoomInBoth changes nothing

Answer 1

Set the zooming factor using setZoomInFactor method on ChartPanel. The parameters in zoomInBoth specify the point where zooming happens.