drawarcs.java

java课件

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

public class DrawArcs extends JFrame {
  public DrawArcs() {
    setTitle("DrawArcs");
    getContentPane().add(new ArcsPanel());
  }

  /** Main method */
  public static void main(String[] args) {
    DrawArcs frame = new DrawArcs();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(250, 300);
    frame.setVisible(true);
  }
}

// The class for drawing arcs on a panel
class ArcsPanel extends JPanel {
  // Draw four blazes of a fan
  protected void paintComponent(Graphics g) {
    super.paintComponent(g);

    int xCenter = getWidth() / 2;
    int yCenter = getHeight() / 2;
    int radius =
      (int)(Math.min(getWidth(), getHeight()) * 0.4);

    int x = xCenter - radius;
    int y = yCenter - radius;

    g.fillArc(x, y, 2 * radius, 2 * radius, 0, 30);
    g.fillArc(x, y, 2 * radius, 2 * radius, 90, 30);
    g.fillArc(x, y, 2 * radius, 2 * radius, 180, 30);
    g.fillArc(x, y, 2 * radius, 2 * radius, 270, 30);
  }
}