Java:使用drawArc绘制一个圆形螺旋

Question

我正在进行java编程练习,我们必须使用drawArc方法绘制一个圆形螺旋,以便结果看起来类似于:

我一直在研究这个问题,这是我到目前为止所做的:

import java.awt.Graphics;
import javax.swing.JPanel;
import javax.swing.JFrame;

public class CircSpiral extends JPanel {
   public void paintComponent(Graphics g) {
      int x = 100;
      int y = 120;
      int width = 40;
      int height = 60;
      int startAngle = 20;
      int arcAngle = 80;
      for (int i = 0; i < 5; i++) {
         g.drawArc(x, y, width, height, startAngle, arcAngle);
         g.drawArc(x + 10, y + 10, width, height, startAngle + 10, arcAngle);
         x = x + 5;
         y = y + 5;
         startAngle = startAngle - 10;
         arcAngle = arcAngle + 10;
      }
   }

   public static void main(String[] args) {
      CircSpiral panel = new CircSpiral();
      JFrame application = new JFrame();
      application.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      application.add(panel);
      application.setSize(300, 300);
      application.setVisible(true);
   }
}

我的代码给了我这个结果:

我知道问题在于我对drawArc方法的参数,因为数字不正确,但我不知道如何使数字以循环方式进行.任何帮助表示赞赏.谢谢!

Answer 1

你的想法几乎是对的.我做了一些修改.您需要反转角度以绘制螺旋的另一侧并使用固定点startAngle.

import java.awt.Graphics;
import javax.swing.JPanel;
import javax.swing.JFrame;

public class CircSpiral extends JPanel {

    public void paintComponent(Graphics g) {
        int x = getSize().width / 2 - 10;
        int y = getSize().height/ 2 - 10;
        int width = 20;
        int height = 20;
        int startAngle = 0;
        int arcAngle = 180;
        int depth = 10;
        for (int i = 0; i < 10; i++) {
            if (i % 2 == 0) {
                //   g.drawArc(x + 10, y + 10, width, height, startAngle + 10, -arcAngle);
                //  x = x - 5;
                y = y - depth;
                width = width + 2 * depth;
                height = height + 2 * depth;
                g.drawArc(x, y, width, height, startAngle, -arcAngle);
            } else {
                //  g.drawArc(x + 10, y + 10, width, height, startAngle + 10, arcAngle);
                x = x - 2 * depth;
                y = y - depth;
                width = width + 2 * depth;
                height = height + 2 * depth;
                g.drawArc(x, y, width, height, startAngle, arcAngle);
            }
        }
    }

    public static void main(String[] args) {
        CircSpiral panel = new CircSpiral();
        JFrame application = new JFrame();
        application.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        application.add(panel);
        application.setSize(300, 300);
        application.setVisible(true);
    }
}

Answer 2

如果这是我的项目,是的,我会在循环中绘制弧形,但在循环内,我会尝试使弧形的边界框更大但仍然居中于同一位置.为了做到这一点,我将x和y递减一些小常量,比如DELTA(我设置为== 1),并且我将增加宽度和高度2 * DELTA.我也想离开我arcAngle不变,而是会改变我的startAngle开始在圈像这样:startAngle = startAngle - arcAngle;.

例如,这个:

import java.awt.Dimension;
import java.awt.Graphics;

import javax.swing.JPanel;
import javax.swing.JFrame;

@SuppressWarnings("serial")
public class CircSpiral extends JPanel {
   private static final int DELTA = 1;
   private static final int ARC_ANGLE = 20;
   private static final int PREF_W = 300;
   private static final int PREF_H = PREF_W;
   private static final int LOOP_MAX = 400;

   public void paintComponent(Graphics g) {
      int x = PREF_W / 2;
      int y = PREF_H / 2;
      int width = 1;
      int height = 1;
      int startAngle = 0;
      int arcAngle = ARC_ANGLE;
      for (int i = 0; i < LOOP_MAX; i++) {
         g.drawArc(x, y, width, height, startAngle, arcAngle);
         x = x - DELTA;
         y = y - DELTA;
         width += 2 * DELTA;
         height += 2 * DELTA;
         startAngle = startAngle - arcAngle;
      }
   }

   @Override
   public Dimension getPreferredSize() {
      if (isPreferredSizeSet()) {
         return super.getPreferredSize();
      }
      return new Dimension(PREF_W, PREF_H);
   }

   public static void main(String[] args) {
      CircSpiral panel = new CircSpiral();
      JFrame application = new JFrame();
      application.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      application.add(panel);
      application.pack();
      application.setLocationRelativeTo(null);
      application.setVisible(true);
   }
}

会导致这个: