java - 在 Java 中绘制线条

Question

如何在 java 中绘制这样的图形？

这是我的代码，它至少要画出这个图的一半

import java.awt.Color;
import java.awt.Graphics;

import javax.swing.JComponent;
import javax.swing.JFrame;

public class Main {
    public static void main(String[] a) {
        JFrame window = new JFrame();
        window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        window.setBounds(30, 30, 300, 300);
        window.getContentPane().add(new MyCanvas());
        window.setVisible(true);
      }
}

class MyCanvas extends JComponent {
    private static final long serialVersionUID = 1L;

    public void paint(Graphics g) {
        int i =0;

        for ( i = 0; i < 100; i++) {
            int x=1+i*3;
            g.drawLine(x, 200, 2+(x+(i/2)), 400-((i*i)/20));
        }
    }
}

我得到了这个。

Answer 1

一个小动画向您展示了您需要寻找的关于线旋转的逻辑。将这条线想象成时钟上的指针。如何为时钟上的一只手制作动画。这几乎是完全相同的概念。唯一的区别是 x1(时钟指针中心点的 x 点)不是保持静止，而是沿着 x 轴(即y1 常量)，而手正在转动。因此，对于时钟的每个滴答声(指针旋转)，x 位置也会水平移动。我就是这么看的。

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;

public class Main {

    public static void main(String[] a) {

        JFrame window = new JFrame();
        window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        window.setResizable(false);
        window.getContentPane().add(new MyCanvas());
        window.pack();
        window.setVisible(true);
    }
}

class MyCanvas extends JPanel {

    int x1 = 0;
    int rotate = 50;

    List<Line> lines;

    Timer timer = null;
    public MyCanvas() {
        lines = new ArrayList<>();

        timer = new Timer(75, new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                if (rotate < -50) {
                    ((Timer) e.getSource()).stop();
                } else {
                    lines.add(new Line(x1, rotate));
                    repaint();
                    x1 += 5;
                    rotate--;
                }
            }
        });

        JButton start = new JButton("Start the Magic");
        start.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e) {
                timer.start();
            }
        });
        add(start);

    }

    public Dimension getPreferredSize() {
        return new Dimension(502, 400);
    }

    private static final long serialVersionUID = 1L;

    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        g.setColor(Color.BLACK);
        g.fillRect(0, 0, getWidth(), getHeight());
        for (Line line : lines) {
            line.drawLine(g);
        }

    }

    class Line {

        int x1;
        int rotate;
        int y1 = 200;

        public Line(int x1, int rotate) {
            this.x1 = x1;
            this.rotate = rotate;
        }

        void drawLine(Graphics g) {
            int Radius = (int) (Math.min(getWidth(), getHeight()) * 0.4);

            int sLength = (int) (Radius * 0.9);
            int xSecond = (int) (x1 + sLength * Math.sin(rotate * (2 * Math.PI / 100)));
            int ySecond = (int) (y1 - sLength * Math.cos(rotate * (2 * Math.PI / 100)));
            g.setColor(Color.GREEN);
            g.drawLine(x1, y1, xSecond, ySecond);
        }
    }
}