Рисование графиков java

import javax.swing.*;
 
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.Toolkit;
import java.awt.geom.*;
 
 
@SuppressWarnings("serial")
class GraphicFrame extends JFrame {
    public GraphicFrame () {
    super();
    setTitle("GraphicBuilder");
    this.setDefaultCloseOperation(EXIT_ON_CLOSE);
    this.setSize(1000, 1000);
    this.setResizable(false);
    setDefaultLookAndFeelDecorated(true);
    this.setPreferredSize(new Dimension(1200, 700));
    Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
        Dimension frameSize = getPreferredSize();
        if (frameSize.height > screenSize.height) {
           frameSize.height = screenSize.height;
        }
        if (frameSize.width > screenSize.width) {
           frameSize.width = screenSize.width;
        }
 setLocation((screenSize.width-frameSize.width) / 2,
(screenSize.height-frameSize.height) / 2);
    pack();
    JPanel panel=new DrawPanel();
    add(panel);
    setVisible(true);
    }
}
 @SuppressWarnings("serial")
class DrawPanel extends JPanel { 
    Rectangle2D rect;
    public DrawPanel() {
    this.rect=new Rectangle2D.Double(300,90,550,550);   
    }
    public void paintComponent (Graphics g) {
    Graphics2D g2=(Graphics2D) g;
    g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
    g2.setColor(Color.BLACK);
    g2.clip(rect);
    // Axis X
    double leftBoundX=-10;
    double rightBoundX=10;
    double stepX=(rightBoundX-leftBoundX)/rect.getWidth(); //1 pt=stepX sm
 
    // Axis Y
    double leftBoundY=-10;
    double rightBoundY=10;
    double stepY=(rightBoundY-leftBoundY)/rect.getHeight(); // 1 pt=stepY sm
    
    // drawing Axis X 
    double zeroPlaceY=-leftBoundY; //sm
    double zeroPlacePtY=zeroPlaceY/stepY;
    g2.drawLine((int)rect.getMinX(),(int)(rect.getMaxY()-zeroPlacePtY),(int)rect.getMaxX(),(int)(rect.getMaxY()-zeroPlacePtY));
    
    // drawing Axis Y
    double zeroPlaceX=-leftBoundX;
    double zeroPlacePtX=zeroPlaceX/stepX;
    g2.drawLine((int)(rect.getMinX()+zeroPlacePtX),(int)rect.getMinY(),(int)(rect.getMinX()+zeroPlacePtX),(int)rect.getMaxY());
    
    // drawing function
    g2.setColor(Color.RED);
    double x=leftBoundX;
    double pointX1=0;
    double pointY1=0;
    boolean flag=false;
    for (double i=rect.getMinX(); i<=rect.getMaxX(); i++) {
    double y=1/x;     // function 
    if (Double.isNaN(y) || Double.isInfinite(y)) {
    x+=stepX;
    flag=true;
    continue;
    }
    double removal=y-leftBoundY;
    double pointY=rect.getMaxY()-removal/stepY; //pixelY
    if (flag) {
    pointX1=i;
    pointY1=pointY;
    flag=false;
    continue;
    }
    x+=stepX;
    if (i==rect.getMinX()) {
    pointX1=rect.getMinX();
    pointY1=pointY;
    continue;
    }
    g2.drawLine((int)pointX1, (int)pointY1, (int)i, (int)pointY);
    pointX1=i;
    pointY1=pointY;
    }
    }
 }
 
public class GraphicBuilder {
    public static void main (String[] args) {
    @SuppressWarnings("unused")
    JFrame frame=new GraphicFrame();
    }
}