java的简单绘图

java简单绘图

import javax.swing.*;
import java.awt.*;
public class Main extends JPanel {

private static final int N = 10;

private static final double P = 0.34;
@Override
protected void paintComponent(Graphics g) {
    super.paintComponent(g);
    Graphics2D g2d = (Graphics2D) g;
    g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

    int width = getWidth();
    int height = getHeight();
    int xOffset = width / 2;
    int yOffset = height / 2;
    g2d.setColor(Color.black);
    g2d.drawLine(50,height-50,width-50,height-50);
    g2d.drawLine(width-60,height-60,width-50,height-50);
    g2d.drawLine(width-60,height-40,width-50,height-50);
    g2d.drawLine(40,60,50,50);
    g2d.drawLine(60,60,50,50);
    g2d.drawLine(50,50,50,height-50);
    g2d.drawString("次数n",width-60,height-20);
    g2d.drawString("期望E",10,50);
    double ex=N*P;
    int jg=(width-50)/20;
    for(int i=0;i<19;i++){
        g2d.drawLine(50+i*jg,height-45,50+i*jg,height-55);
        String kb=String.format("%d",i);
        int fontwidth=g2d.getFontMetrics().stringWidth(kb)/2;
        g2d.drawString(kb,50+i*jg-fontwidth, height-20);
    }
    jg=(height-50)/20;
    for(int i=0;i<19;i++){
        g2d.drawLine(45,height-50-i*jg,55,height-50-i*jg);
        double kbb=0.2+i*0.01;
        String kb=String.format("%.2f",kbb);
        int fontwidth=g2d.getFontMetrics().stringWidth(kb);
        int fontheight=g2d.getFontMetrics().getHeight()/3;
        g2d.drawString(kb,40-fontwidth,height-50-i*jg+fontheight);
    }
    g2d.setStroke(new BasicStroke(5));
    g2d.setColor(Color.cyan);
    g2d.fillRect(50+10*(width-50)/20-6,height-50-14*(height-50)/20+6,5,5);
    Stroke dash = new BasicStroke(2.5f, BasicStroke.CAP_BUTT, BasicStroke.JOIN_ROUND, 3.5f, new float[] { 15, 10, }, 0f);
    g2d.setColor(Color.yellow);
    g2d.setStroke(dash);
    g2d.drawLine(50+10*(width-50)/20-6,height-50-14*(height-50)/20+20,50+10*(width-50)/20-6,height-55);
    g2d.drawLine(50+10*(width-50)/20-20,height-50-14*(height-50)/20+6,50,height-50-14*(height-50)/20+6);
    System.out.println("期望: 0.34");
}
private double binomialProbability(int n, int k, double p) {
    return combination(n, k) * Math.pow(p, k) * Math.pow(1 - p, n - k);
}

private long combination(int n, int k) {
    if (k == 0 || k == n) {
        return 1;
    }
    if (k > n - k) {
        k = n - k;
    }
    long result = 1;
    for (int i = 1; i <= k; i++) {
        result *= (n - i + 1);
        result /= i;
    }
    return result;
}

public static void main(String[] args) {
    JFrame frame = new JFrame("Binomial Distribution Graph");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(800, 600);
    frame.add(new Main());
    frame.setVisible(true);
}

}