绘制组件的图形比例 (xmin,xmax,ymin,ymax)

Question

我得到了一个用多项式函数制作图形的学校项目（例如 2x^2+2x+4）。将 JFrame 与paintComponent 一起使用，我从多项式函数的结果中为 x 画线。这将在 xmin,xmax,ymin 和 ymax 的区域内，之后 mouselistener 将显示我的鼠标光标在图形上的点，它的点位于 x 线和 y 线。(Example of done program)

编辑： 我需要做什么才能从 Wykres 类中访问变量。制作Wykres wykres = new Wykres()；使程序卡住。我是否需要使用计算多项式函数的方法将 actionperformed 中的变量添加到新类 Silnik 以及如何实现？

我们将不胜感激。

package zad8v2;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridLayout;
import java.awt.Point;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.geom.Line2D;
import java.util.ArrayList;
import java.util.Collections;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
import javax.swing.AbstractListModel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import javax.swing.event.ListSelectionEvent;

public class Draw {
public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {

        @Override
        public void run() {
            new Wykres();
        }
    });
}
}

class Wykres implements ActionListener {
JTextField f1, f2, f3, f4, f5;
double a, b, c, delta, x1, x2, xmin, xmax, ymin, ymax;

public Wykres() {
    // tworzenie
    JFrame jf = new JFrame();
    Rysowanie rys = new Rysowanie();
    JPanel jp = new JPanel();
    f1 = new JTextField();
    f2 = new JTextField();
    f3 = new JTextField();
    f4 = new JTextField();
    f5 = new JTextField();

    JPanel pomoc = new JPanel();
    pomoc.setLayout(new GridLayout(1, 4));
    pomoc.add(f1);
    pomoc.add(f2);
    pomoc.add(f3);
    pomoc.add(f4);

    jf.setLayout(new BorderLayout());
    jf.add(rys, BorderLayout.NORTH);
    jf.add(pomoc, BorderLayout.CENTER);
    jf.add(f5, BorderLayout.SOUTH);
    f5.addActionListener(this);
    jf.pack();

    // Podstawa
    jf.setVisible(true);
    jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

}

public double getXmin() {
    return xmin;
}

public void setXmin(double xmin) {
    this.xmin = xmin;
}

public double getXmax() {
    return xmax;
}

public void setXmax(double xmax) {
    this.xmax = xmax;
}

public double getYmin() {
    return ymin;
}

public void setYmin(double ymin) {
    this.ymin = ymin;
}

public double getYmax() {
    return ymax;
}

public void setYmax(double ymax) {
    this.ymax = ymax;
}

@Override
public void actionPerformed(ActionEvent e) {
    /*
     * if (f1.getText() == "" && f2.getText() == "" && f3.getText() == "" &&
     * f4.getText() == "") { f1.setText("Wpisz xmin"); f2.setText("Wpisz xmax");
     * f3.setText("Wpisz ymin"); f4.setText("Wpisz ymax"); } else {
     */
    String f1s = f1.getText();
    String f2s = f2.getText();
    String f3s = f3.getText();
    String f4s = f4.getText();
    double xmin = Double.parseDouble(f1s);
    double xmax = Double.parseDouble(f2s);
    double ymin = Double.parseDouble(f3s);
    double ymax = Double.parseDouble(f4s);

    String wielomian = f5.getText();
    String[] czesci = wielomian.split("x\\^\\d+\\+?");
    String as = czesci[0];
    String bs = czesci[1];
    String cs = czesci[2];

    a = Double.parseDouble(as);
    b = Double.parseDouble(bs);
    c = Double.parseDouble(cs);

    System.out.println(f1s);
    System.out.println(f2s);
    System.out.println(f3s);
    System.out.println(f4s);
    System.out.println(a);
    System.out.println(b);
    System.out.println(c);

    if (a == 0) {
        f5.setText(f5.getText() + "Nie jest to równanie kwadratowe");
        f5.setBackground(Color.RED);
    } else {
        delta = Math.pow(b, 2) - 4 * a * c;
        if (delta < 0) {
            f5.setText(f5.getText() + "Brak miejsc zerowych");
            f5.setBackground(Color.RED);
        } else if (delta == 0) {
            x1 = (-b) / 2 * a;
            String s1 = String.valueOf(x1);
            f5.setBackground(Color.WHITE);
            f5.setForeground(Color.BLUE);
        } else if (delta > 0) {
            x1 = (-b - Math.sqrt(delta)) / (2 * a);
            String s1 = String.valueOf(x1);
            x2 = (-b + Math.sqrt(delta)) / (2 * a);
            String s2 = String.valueOf(x2);
            f5.setForeground(Color.BLUE);
            f5.setBackground(Color.WHITE);
            System.out.println(s1 + " " + s2);
        }
    }
}

}

class Silnik {
public Silnik() {

}
}

class Rysowanie extends JPanel {

int yCross;
int xCross;

public Rysowanie() {
    setPreferredSize(new Dimension(400, 400));
    addComponentListener(new ComponentAdapter() {

        @Override
        public void componentResized(ComponentEvent e) {
            setSize(new Dimension(400, getHeight()));
            super.componentResized(e);
            repaint();
        }

    });
    addMouseMotionListener(new MouseMotionListener() {
        @Override
        public void mouseMoved(MouseEvent e) {
            Point point = e.getPoint();
            Rysowanie.this.xCross = point.x;
            Rysowanie.this.yCross = point.y;
            Rysowanie.this.repaint();
        }

        @Override
        public void mouseDragged(MouseEvent e) {
        }
    });
    }

public void paintComponent(Graphics g) {

    Wykres wykres = new Wykres();
    double xmin = wykres.getXmin();
    double xmax = wykres.getXmax();

    /*
     * g.drawLine(Xmin, Ymax, Xmax, Ymax); g.drawLine(Xmin, Ymax, Xmin,     Ymin);
     */
    g.clearRect(0, 0, 400, 400);
    g.setColor(Color.BLUE);
    g.drawLine(0, getHeight() / 2, getWidth(), getHeight() / 2);
    g.setColor(Color.BLACK);
    g.drawLine((int) (getWidth() / 2), 0, (int) (getWidth() / 2),     getHeight());

    g.setColor(Color.RED);
    /*
     * g.drawLine((int) (getWidth() / Math.abs(xmin) + Math.abs(xmax), 200, (int)
     * (getWidth() / 2), getHeight());
     */

    // krzyz
    g.setColor(Color.BLACK);
    g.drawLine(getWidth() / 2, yCross, xCross, yCross);
    g.drawLine(xCross, getHeight() / 2, xCross, yCross);

    /*
     * //OX for(int i=0;i<=400;i=i+50) if(i!=200) g.drawString(new
     * Integer(i-200).toString(),i, 210);
     * 
     * //OY for(int i=0;i<=400;i=i+50) if(i!=200) g.drawString(new
     * Integer((i-200)*-1).toString(),200, i);
     */
}
}

/*
     * public class RysSilnik {
 * 
     * public static int makePointX(int W, double xmin, double thisX, double
     * xmax,String wzor) { int obl = (int) (W / (Math.abs(xmin) +                 Math.abs(xmax)));
 * double thisX = Wykres.getX(wzor,thisY); int pktSt = (int) ((W / 2) +     (thisX *
 * pktSt)); return pktSt; }
 * 
 * public static int makePointY(int H, double ymin, double thisY, double     ymax,
 * String wzor) { int obl = (int) (H / (Math.abs(ymin) + Math.abs(ymax)));
 * double thisY = Wykres.getY(wzor,thisX); int pktSt = (int) ((H / 2) + (thisY *
 * pktSt)); return pktSt; } } }
 */

Answer 1

做了这样的事情：当鼠标鼠标保存值时，向绘图组件添加一个 mmouse 动作，然后在你的绘图中重用它来绘制你的 2 行

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;

import javax.swing.JPanel;

class Rysowanie extends JPanel {

    protected int yCross;
    protected int xCross;

    public Rysowanie() {
        setPreferredSize(new Dimension(400, 400));
        addMouseMotionListener(new MouseMotionListener() {

            @Override
            public void mouseMoved(MouseEvent e) {
                Point point = e.getPoint();
                Rysowanie.this.xCross = point.x;
                Rysowanie.this.yCross = point.y;
                Rysowanie.this.repaint();
            }

            @Override
            public void mouseDragged(MouseEvent e) {
                // nothing to do here
            }
        });
    }

    public void paintComponent(Graphics g) {

        /*
         * g.drawLine(Xmin, Ymax, Xmax, Ymax); g.drawLine(Xmin, Ymax, Xmin, Ymin);
         */
        g.clearRect(0, 0, 400, 400);
        g.setColor(Color.BLUE);
        g.drawLine(0, getHeight() / 2, getWidth(), getHeight() / 2);
        g.setColor(Color.BLACK);
        g.drawLine((int) (getWidth() / 2), 0, (int) (getWidth() / 2), getHeight());

        g.setColor(Color.RED);
        g.drawLine((int) (getWidth() / 2), 200, (int) (getWidth() / 2), getHeight());


        // draw the cross
        g.setColor(Color.BLACK);
        g.drawLine(getWidth() / 2, yCross, xCross, yCross);
        g.drawLine(xCross, getHeight() / 2, xCross, yCross);


        /*
         * //OX for(int i=0;i<=400;i=i+50) if(i!=200) g.drawString(new
         * Integer(i-200).toString(),i, 210);
         * 
         * //OY for(int i=0;i<=400;i=i+50) if(i!=200) g.drawString(new
         * Integer((i-200)*-1).toString(),200, i);
         */
    }
}

/*
 * public class RysSilnik {
 * 
 * public static int makePointX(int W, double xmin, double thisX, double
 * xmax,String wzor) { int obl = (int) (W / (Math.abs(xmin) + Math.abs(xmax)));
 * double thisX = Wykres.getX(wzor,thisY); int pktSt = (int) ((W / 2) + (thisX *
 * pktSt)); return pktSt; }
 * 
 * public static int makePointY(int H, double ymin, double thisY, double ymax,
 * String wzor) { int obl = (int) (H / (Math.abs(ymin) + Math.abs(ymax)));
 * double thisY = Wykres.getY(wzor,thisX); int pktSt = (int) ((H / 2) + (thisY *
 * pktSt)); return pktSt; } } }
 */