Zoom graphics on JPanel

Question

I am currently trying to figure out how to zoom in a JPanel that has graphics drawn on it. The JPanel is currently embedded in a JScrollPane, which should allow the user to scroll when the zoom level is above 100%.

Right now, I am able to zoom in the panel properly, but the AffineTransform is not applied to the mouse events. Also, when the scrollBars are visible, they are way too long. I don't want them to be longer than the original size of the JPanel.

private AffineTransform m_zoom;

@Override
protected void paintComponent(Graphics p_g) {
    if (m_mainWindow != null) {
        m_zoom = ((Graphics2D) p_g).getTransform();
        m_zoom.scale(m_scale, m_scale);
        ((Graphics2D) p_g).transform(m_zoom);

        super.paintComponent(p_g);
    }
    p_g.dispose();
}

public void setScale(double p_scale) {
    m_scale = p_scale;
    repaint();
    revalidate();
}

If someone could help me with all this, that would be very appreciated! Thank you

Answer 1

Ok I figured out what was going on with the JScrollPane. I adjusted the size of the JPanel manually according to new zoom level and it worked.

public void setScale(double p_newScale) {
    m_scale = p_newScale;
    int width = (int) (getWidth() * m_scale);
    int height = (int) (getHeight() * m_scale);
    setPreferredSize(new Dimension(width, height));
    repaint();
    revalidate();
}

I still need to find a way to calculate the position of the mouse with the JPanel zoomed in/out. Should I override the mouseClicked and mouseMoved methods directly in my custom JPanel class?

EDIT:

I used a simple division for the relative coordinates on my JPanel. It worked out very well for both mouseMoved and mouseClicked.

Point zoomedLocation = new Point((int)(evt.getPoint().x / m_zoomFactor),
            (int)(evt.getPoint().y / m_zoomFactor));

And I am using zoomedLocation everywhere instead of evt.getPoint().