import java.awt.*;
import javax.swing.*;  // for JApplet

public class SpiderWeb extends JApplet {

  public void paint (Graphics g) {
    
    //int height = (int)(g.getClipBounds().getHeight());
    //int width = (int)(g.getClipBounds().getWidth());
    int height = getHeight();
    int width = getWidth();
    
    // Draw circles in web
    for (int radius=1; 2*radius < Math.min(width, height); radius = radius + 25) {
      drawCircle(g, Color.black, width/2, height/2, radius);
    }

    // Draw lines in web that span the x-axis
    int numLines = 8;
    for (int i=0; i<height; i = i + height/(numLines-1)) {
      g.drawLine(0, i, width, height-i);
    }

    // Draw lines in web that span the y-axis
    for (int j=0; j<width-numLines; j = j + width/(numLines-1)) {
      g.drawLine(j, 0, width-j, height);
    }
    
    // Draw random colored/positioned spiders
    int numSpiders = 10;
    for (int k=0; k<numSpiders; k++) {
      Color spiderColor = new Color((int)(Math.random()*Integer.MAX_VALUE));
      int spiderRadius = 5+k;  // Smallest spider has radius 5. Spiders get incrementally bigger
      int spiderX = spiderRadius+(int)(Math.random()*(width-2*spiderRadius));
      int spiderY = spiderRadius+(int)(Math.random()*(height-2*spiderRadius));
      drawSpider(g, spiderColor, spiderX, spiderY, spiderRadius);
    }
    
  }

  // Draw an unfilled circle colored c centered at (x,y) with radius r 
  // in graphics context g.  Leave the current graphics color invariant.
  public static void drawCircle (Graphics g, Color c, int x, int y, int r) {
    Color savedColor = g.getColor();
    g.setColor(c);
    g.drawOval(x - r, y - r, 2*r, 2*r);  // Be careful of fencepost errors!
    g.setColor(savedColor);
  }

  // Draw a spider as a filled circle and four lines (legs).
  // Draw a filled circle colored c centered at (x,y) with radius r
  // in graphics context g.  Draw four lines representing spider legs.
  // Leave the current graphics color invariant. 
  public static void drawSpider(Graphics g, Color c, int x, int y, int r) {
    Color savedColor = g.getColor();
    g.setColor(c);
    g.fillOval(x - r, y - r, 2*r, 2*r);  // Be careful of fencepost errors!
    
    // Draw 4 legs
    for (double angle=Math.PI/8; angle<Math.PI; angle = angle + Math.PI/4) {
      g.drawLine(x + (int)(Math.cos(angle)*r*1.2), y + (int)(Math.sin(angle)*r*1.2),
                 x + (int)(Math.cos(angle+Math.PI)*r*1.2), y + (int)(Math.sin(angle+Math.PI)*r*1.2));
    }
    
    g.setColor(savedColor);
  }
  
}