Das Zoomen in Mandelbrot-Menge Fraktale in Java

Ich bin Anfang zu machen, ein apfelmännchen-fraktal-viewer. Ich habe eine Menge Probleme, wenn es um das Zoomen in das fraktal. Wenn Sie versuchen, um zu vergrößern, wird der Betrachter gerade in der Nähe auf der center. Ich habe so viel getan, wie ich kann, um zu verstehen dieses dilemma. Wie kann ich zoom-in auf meine Fraktale in der Weise, dass, wenn ich zu vergrößern, Sie werden vergrößern auf die Mitte des Bildschirms, und nicht das Zentrum des fraktalen?

import java.awt.*;
import java.awt.image.BufferedImage;
import javax.swing.*;
import java.awt.event.*;



public class Mandelbrot extends JFrame implements ActionListener {

    private JPanel ctrlPanel;
    private JPanel btnPanel;
    private int numIter = 50;
    private double zoom = 130;
    private double zoomIncrease = 100;
    private int colorIter = 20;
    private BufferedImage I;
    private double zx, zy, cx, cy, temp;
    private int xMove, yMove = 0;
    private JButton[] ctrlBtns = new JButton[9];
    private Color themeColor = new Color(150,180,200);

    public Mandelbrot() {
        super("Mandelbrot Set");
        setBounds(100, 100, 800, 600);
        setResizable(false);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        plotPoints();

        Container contentPane = getContentPane();

        contentPane.setLayout(null);




        ctrlPanel = new JPanel();
        ctrlPanel.setBounds(600,0,200,600);
        ctrlPanel.setBackground(themeColor);
        ctrlPanel.setLayout(null);

        btnPanel = new JPanel();
        btnPanel.setBounds(0,200,200,200);
        btnPanel.setLayout(new GridLayout(3,3));
        btnPanel.setBackground(themeColor);

        ctrlBtns[1] = new JButton("up");
        ctrlBtns[7] = new JButton("down");
        ctrlBtns[3] = new JButton ("left");
        ctrlBtns[5] = new JButton("right");
        ctrlBtns[2] = new JButton("+");
        ctrlBtns[0] = new JButton("-");
        ctrlBtns[8] = new JButton(">");
        ctrlBtns[6] = new JButton("<");
        ctrlBtns[4] = new JButton();

        contentPane.add(ctrlPanel);
        contentPane.add(new imgPanel());
        ctrlPanel.add(btnPanel);

        for (int x = 0; x<ctrlBtns.length;x++){
            btnPanel.add(ctrlBtns[x]);
            ctrlBtns[x].addActionListener(this);
        }

        validate();

    }

    public class imgPanel extends JPanel{
        public imgPanel(){
            setBounds(0,0,600,600);

        }

        @Override
        public void paint (Graphics g){
            super.paint(g);
            g.drawImage(I, 0, 0, this);
        }
    }

    public void plotPoints(){
        I = new BufferedImage(getWidth(), getHeight(), BufferedImage.TYPE_INT_RGB);
        for (int y = 0; y < getHeight(); y++) {
            for (int x = 0; x < getWidth(); x++) {
                zx = zy = 0;
                cx = (x - 320+xMove) / zoom;
                cy = (y - 290+yMove) / zoom;
                int iter = numIter;
                while (zx * zx + zy * zy < 4 && iter > 0) {
                    temp = zx * zx - zy * zy + cx;
                    zy = 2 * zx * zy + cy;
                    zx = temp;
                    iter--;
                }
                I.setRGB(x, y, iter | (iter << colorIter));
            }
        }
    }

    public void actionPerformed(ActionEvent ae){
        String event = ae.getActionCommand();

        switch (event){
        case "up":
            yMove-=100;
            break;
        case "down":
            yMove+=100;
            break;
        case "left":
            xMove-=100;
            break;
        case "right":
            xMove+=100;
            break;
        case "+":
            zoom+=zoomIncrease;
            zoomIncrease+=100;
            break;
        case "-":
            zoom-=zoomIncrease;
            zoomIncrease-=100;
            break;
        case ">":
            colorIter++;
            break;
        case "<":
            colorIter--;
            break;
        }



        plotPoints();
        validate();
        repaint();
    }




    public static void main(String[] args) {
        new Mandelbrot().setVisible(true);
    }
}