import java.awt.*;
import javax.swing.*;

public class ExtraPixelProblem extends JComponent {

  ////////////////////////////////////////////////
  // Paint
  ////////////////////////////////////////////////

  public void paint(Graphics page) {
    boolean useBrokenVersion = false; // <-- Edit to see broken/working version
    if (useBrokenVersion)
      brokenPaint(page);
    else
      fixedPaint(page);
  }
  
  ////////////////////////////////////////////////
  // Broken paint
  // Demonstrates the "extra pixel" or "thin white stripe" problem
  ////////////////////////////////////////////////

  public void brokenPaintStripe(Graphics page, int stripe, int stripes, Color color) {   
    int height = getHeight()/stripes;
    int top = stripe * height;

    page.setColor(color);
    page.fillRect(0, top, getWidth(), height);
    
    page.setColor(Color.white);
    page.drawString("stripe #" + stripe + " height = " + height, 20, top+20);
  }

  public void brokenPaint(Graphics page) {
    page.setColor(Color.red);
    page.fillRect(0, 0, getWidth(), getHeight());
    
    brokenPaintStripe(page, 0, 3, Color.black);
    brokenPaintStripe(page, 1, 3, Color.blue);
    brokenPaintStripe(page, 2, 3, Color.black);

    int height = getHeight();
    int extraPixels = height % 3;
    String msg = "";
    page.setColor((extraPixels == 0) ? Color.white : Color.red);
   
    if (extraPixels == 0) {
      page.setColor(Color.white);
      msg = "so there are no extra pixels (no red line below!)";
    }
    else {
      page.setColor(Color.red);
      msg = "so there is a " + extraPixels + "-pixel red line below!";
    }

    page.drawString("window height = " + height +
                    " = (3*" + (height/3) + ") + " + extraPixels + ", " + msg,
                    20, height-15);
  }

  ////////////////////////////////////////////////
  // Fixed paint
  // Fixes the "extra pixel" or "thin white stripe" problem
  ////////////////////////////////////////////////

  public void fixedPaintStripe(Graphics page, int stripe, int stripes, Color color) {   
    int top = stripe * getHeight()/stripes;
    int nextTop = (stripe+1) * getHeight()/stripes;
    int height = nextTop - top;

    page.setColor(color);
    page.fillRect(0, top, getWidth(), height);
    
    page.setColor(Color.white);
    page.drawString("stripe #" + stripe + " height = " + height, 20, top+20);
  }

  public void fixedPaint(Graphics page) {
    page.setColor(Color.red);
    page.fillRect(0, 0, getWidth(), getHeight());
    
    fixedPaintStripe(page, 0, 3, Color.black);
    fixedPaintStripe(page, 1, 3, Color.blue);
    fixedPaintStripe(page, 2, 3, Color.black);

    int height = getHeight();
    int extraPixels = height % 3;
    String msg = "";
    page.setColor((extraPixels == 0) ? Color.white : Color.red);
   
    page.setColor(Color.white);
    page.drawString("window height = " + height,
                    20, height-15);
  }

  //////////////////////////////////////////////
  ///           END OF YOUR CODE             ///
  ///  (you may ignore all the code below!!! ///
  //////////////////////////////////////////////

  public Dimension getPreferredSize() {
    int initialWidth = 500;
    int initialHeight = 302; // so there are 2 pixels left over!
    return new Dimension(initialWidth, initialHeight);
  }

  public static void main(String[] args) {
    JComponent jc = newInstance();
    JFrame frame = new JFrame(jc.getClass().getName());
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    JPanel cp = new JPanel();
    cp.setLayout(new BorderLayout());
    cp.add(jc);
    frame.setContentPane(cp);
    frame.pack();
    frame.setVisible(true);
  }

  // Returns an instance of this class as a JComponent.  This is necessary so
  // students can rename this class without changing the "main" method's body.
  public static JComponent newInstance() {
    StackTraceElement[] trace = null;
    try { throw new RuntimeException(); }
    catch (Exception e) { trace = e.getStackTrace(); }
    try { return (JComponent)Class.forName(trace[0].getClassName()).newInstance(); }
    catch (Exception e) { return null; }
  }
}