public void createAndShowGUI() {
      window = new JFrame();       ➀
         //...
      canvas = new JPanel () {     ➁
	      //...
          }
      };
    canvas.setBackground(Color.white);
    window.getContentPane().add (canvas, BorderLayout.CENTER);  ➂
    canvas.setPreferredSize(new Dimension(400, 400));
    
    JPanel controls = new JPanel();                             ➃
    
    colorChooser1 = new JButton("Color 1");                     ➄
    controls.add (colorChooser1);
      //...
    colorChooser2 = new JButton("Color 2");
    controls.add (colorChooser2);
      //...
    stepSizeIn = new JTextField (""+stepSize, 5);
    controls.add (stepSizeIn);
      //...
    window.getContentPane().add (controls, BorderLayout.SOUTH);  ➅
      //...
    window.pack();                                               ➆
    window.setVisible(true);
  }

  public void createAndShowGUI() {
      window = new JFrame();
      // set up the components
      window.getContentPane().setLayout (new BorderLayout());
    
      canvas = new JPanel () {
	      //...
          }
      };
    canvas.setBackground(Color.white);
    window.getContentPane().add (canvas, BorderLayout.CENTER);
canvas.setPreferredSize(new Dimension(400, 400));  ➀
    
    JPanel controls = new JPanel();
    
    colorChooser1 = new JButton("Color 1");
    controls.add (colorChooser1);
    setColor(colorChooser1, colors[0]);
    colorChooser1.addActionListener (new ColorChooser(colorChooser1, 0));
    
    colorChooser2 = new JButton("Color 2");
    controls.add (colorChooser2);
    setColor(colorChooser2, colors[1]);
    colorChooser2.addActionListener (new ColorChooser(colorChooser2, 1));
    
    stepSizeIn = new JTextField (""+stepSize, 5);
    controls.add (stepSizeIn);
    stepSizeIn.addActionListener (new ActionListener()
      {
        public void actionPerformed(ActionEvent e) {
          try {
            Integer newSize = new Integer(stepSizeIn.getText());
            stepSize = newSize.intValue();
            canvas.repaint();
          } catch (Exception ex) {};
        }
      });

    window.getContentPane().add (controls, BorderLayout.SOUTH);
    
    window.setDefaultCloseOperation((startedInAnApplet) ? JFrame.DISPOSE_ON_CLOSE : JFrame.EXIT_ON_CLOSE);
    
    window.pack();
    window.setVisible(true);
  }

  /**
   * Sets the background color of a button to the indicated color.
   * Changes the foreground to wither black or white, depending on
   * which will give more contrast agasint the new background.
   * 
   * @param button
   * @param color
   */
  private void setColor(JButton button, Color color) {   ➁
    button.setBackground(color);
    int brightness = color.getRed() + color.getGreen() + color.getBlue(); // max of 3*255
    if (brightness > 3*255/2) {
        // This is a fairly bright color. Use black lettering
        button.setForeground (Color.black);
    } else {
        // This is a fairly dark color. Use white lettering
        button.setForeground (Color.white);
    }
}

  private class ColorChooser implements ActionListener {
      private JButton button;          ➀
      private int colorNum;

      public ColorChooser (JButton button, int colorNum) {
          this.button = button;        ➁
          this.colorNum = colorNum;
      }

      @Override
      public void actionPerformed(ActionEvent arg0) {   ➂
          Color chosen = JColorChooser.showDialog(window, "Choose a color", 
                  colors[colorNum]);
          if (chosen != null) {
              colors[colorNum] = chosen;   ➃
              setColor (button, chosen);
              canvas.repaint();
          }
      }
  };

  private class ColorChooser implements ActionListener {
      private JButton button;
      private int colorNum;

      public ColorChooser (JButton button, int colorNum) {
          this.button = button;
          this.colorNum = colorNum;
      }

      @Override
      public void actionPerformed(ActionEvent arg0) {
          Color chosen = JColorChooser.showDialog(window, "Choose a color", colors[colorNum]);
          if (chosen != null) {
              colors[colorNum] = chosen;
              setColor (button, chosen);
              canvas.repaint();
          }
      }
  };


  public void createAndShowGUI() {
      window = new JFrame();
      // set up the components
      window.getContentPane().setLayout (new BorderLayout());
    
      canvas = new JPanel () {
          public void paint (Graphics g) {
              super.paint(g);
              drawLines (g, getSize());
          }
      };
    canvas.setBackground(Color.white);
    window.getContentPane().add (canvas, BorderLayout.CENTER);
    canvas.setPreferredSize(new Dimension(400, 400));
    
    JPanel controls = new JPanel();
    
    colorChooser1 = new JButton("Color 1");
    controls.add (colorChooser1);
    setColor(colorChooser1, colors[0]);
    colorChooser1.addActionListener (new ColorChooser(colorChooser1, 0));
    
    colorChooser2 = new JButton("Color 2");
    controls.add (colorChooser2);
    setColor(colorChooser2, colors[1]);
    colorChooser2.addActionListener (new ColorChooser(colorChooser2, 1));
    
    stepSizeIn = new JTextField (""+stepSize, 5);
    controls.add (stepSizeIn);
    stepSizeIn.addActionListener (new ActionListener()
      {
        public void actionPerformed(ActionEvent e) {
          try {
            Integer newSize = new Integer(stepSizeIn.getText());
            stepSize = newSize.intValue();
            canvas.repaint();
          } catch (Exception ex) {};
        }
      });

    window.getContentPane().add (controls, BorderLayout.SOUTH);
    
    window.setDefaultCloseOperation((startedInAnApplet) ? JFrame.DISPOSE_ON_CLOSE : JFrame.EXIT_ON_CLOSE);
    
    window.pack();
    window.setVisible(true);
  }

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;

import javax.swing.JApplet;
import javax.swing.JButton;
import javax.swing.JColorChooser;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;

/**
 * A simple example of GUI event handling in a Java application.
 * 
 * This can be run as a main program or as an applet.
 * 
 * @author zeil
 *
 */


public class StringArt extends JApplet {

  private boolean startedInAnApplet;
	
// The Model
  private Color[] colors;
  private int stepSize = 5;
  
  // The View & Controls
  private JFrame window;
  private JPanel canvas;
  private JButton colorChooser1;
  private JButton colorChooser2;
  private JTextField stepSizeIn;
  

  private class ColorChooser implements ActionListener {
      private JButton button;
      private int colorNum;

      public ColorChooser (JButton button, int colorNum) {
          this.button = button;
          this.colorNum = colorNum;
      }

      @Override
      public void actionPerformed(ActionEvent arg0) {
          Color chosen = JColorChooser.showDialog(window, "Choose a color", colors[colorNum]);
          if (chosen != null) {
              colors[colorNum] = chosen;
              setColor (button, chosen);
              canvas.repaint();
          }
      }
  };

  public StringArt()
  {
      startedInAnApplet = false;
      window = null;
      colors = new Color[2];
      colors[0] = Color.red;
      colors[1] = Color.blue;
  }
  
  
  public static void main (String[] args)
  {
      StringArt instance = new StringArt();
      instance.createAndShowGUI();  
  }
  
  public void createAndShowGUI() {
      window = new JFrame();
      // set up the components
      window.getContentPane().setLayout (new BorderLayout());
    
      canvas = new JPanel () {
          public void paint (Graphics g) {
              super.paint(g);
              drawLines (g, getSize());
          }
      };
    canvas.setBackground(Color.white);
    window.getContentPane().add (canvas, BorderLayout.CENTER);
    canvas.setPreferredSize(new Dimension(400, 400));
    
    JPanel controls = new JPanel();
    
    colorChooser1 = new JButton("Color 1");
    controls.add (colorChooser1);
    setColor(colorChooser1, colors[0]);
    colorChooser1.addActionListener (new ColorChooser(colorChooser1, 0));
    
    colorChooser2 = new JButton("Color 2");
    controls.add (colorChooser2);
    setColor(colorChooser2, colors[1]);
    colorChooser2.addActionListener (new ColorChooser(colorChooser2, 1));
    
    stepSizeIn = new JTextField (""+stepSize, 5);
    controls.add (stepSizeIn);
    stepSizeIn.addActionListener (new ActionListener()
      {
        public void actionPerformed(ActionEvent e) {
          try {
            Integer newSize = new Integer(stepSizeIn.getText());
            stepSize = newSize.intValue();
            canvas.repaint();
          } catch (Exception ex) {};
        }
      });

    window.getContentPane().add (controls, BorderLayout.SOUTH);
    
    window.setDefaultCloseOperation((startedInAnApplet) ? JFrame.DISPOSE_ON_CLOSE : JFrame.EXIT_ON_CLOSE);
    
    window.pack();
    window.setVisible(true);
  }
  
  /**
   * Sets the background color of a button to the indicated color.
   * Changes the foreground to wither black or white, depending on
   * which will give more contrast agasint the new background.
   * 
   * @param button
   * @param color
   */
  private void setColor(JButton button, Color color) {
    button.setBackground(color);
    int brightness = color.getRed() + color.getGreen() + color.getBlue(); // max of 3*255
    if (brightness > 3*255/2) {
        // This is a fairly bright color. Use black lettering
        button.setForeground (Color.black);
    } else {
        // This is a fairly dark color. Use white lettering
        button.setForeground (Color.white);
    }
}

  // Applet functions
  
  public void init() {
      startedInAnApplet = true;
  }

public void start() {
    if (window == null)
        createAndShowGUI();
  }
  
  public void stop() {
  }
  
  public void destroy() {
  }
  
  
  
  
  int interpolate (int x, int y, int i, int steps)
  {
    return (i * x + (steps-i)*y) / steps;
  }
  
  
  Color interpolate(Color c1, Color c2, int i, int steps)
  {
    return new Color (interpolate(c1.getRed(), c2.getRed(), i, steps),
                      interpolate(c1.getGreen(), c2.getGreen(), i, steps),
                      interpolate(c1.getBlue(), c2.getBlue(), i, steps));
  }
  

  class Point {
    double x;
    double y;
  }

  Point ptOnCircle (int degrees, int radius, Point center) 
  {
    Point p = new Point();
    double theta = Math.toRadians((double)degrees);
    p.x = center.x + (double)radius * Math.cos(theta);
    p.y = center.y + (double)radius * Math.sin(theta);
    return p;
  }

  public void drawLines(Graphics g, Dimension d)
  {
    int dmin = (d.width < d.height) ? d.width : d.height;
    
    if (stepSize < 1)
      stepSize = 1;

    Point center = new Point();
    center.x = (double)d.width/2.0;
    center.y = (double)d.height/2.0;

    for (int i = 0; i < 60; ++i) {
      Point origin = ptOnCircle(6*i, dmin/2, center);
      int j = i + stepSize;
      while (j >= 60)
        j -= 60;
      while (i != j) {
        Point destination = ptOnCircle(6*j, dmin/2, center);
        g.setColor(interpolate(interpolate(colors[0], colors[1], i%30, 30),
                               interpolate(colors[0], colors[1], j, 60),
                               1, 2));
        g.drawLine ((int)origin.x, (int)origin.y,
                    (int)destination.x, (int)destination.y);
        j += stepSize;
        while (j >= 60)
          j -= 60;
      }
    }
  }
  
  
}

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

import javax.swing.JButton;

/**
 * The core data and drawing algorithm for the CS330 string art program.
 * 
 * @author zeil
 *
 */
public class StringArtModel {

	/**
	 * The two colors used in drawing the picture.
	 * Lines are shaded gradually from colors[0]
	 * to colors[1].
	 */
    private Color[] colors;    
	
	/**
	 * Each of the 60 points around the circle will get
	 * a line connecting it to the points k*stepSize away,
	 * for all values of k (until we start to repeat
	 * the same lines).
	 */
	private int stepSize = 5;    ➁


	/**
	 * Create a new set of model data.
	 */
	public StringArtModel() {
		colors = new Color[2];
		colors[0] = Color.red;
		colors[1] = Color.blue;
	}

	/**
	 * Get the value of one of the colors.
	 * @param colorNum an integer in the range 0..1
	 * @return the requested color.
	 */
    public Color getColor(int colorNum) {     ➂
		return colors[colorNum];
	}

	/**
	 * Change the value of one of the colors.
	 * @param colorNum an integer in the range 0..1
	 * @param color the desired color
	 */
	public void setColor(int colorNum, Color color) {  ➂
		colors[colorNum] = color;
	}

	/**
	 * Get the current step size.  When drawLines is called,
	 * each of the 60 points around the circle will get
	 * a line connecting it to the points k*getStepSize() away,
	 * for all values of k (until we start to repeat
	 * the same lines).
	 * 
	 * @return the step size
	 */
	public int getStepSize() {     ➂
		return stepSize;
	}

	/**
	 * Change the step size value.
	 * @param newStepSize the desired step size
	 */
	public void setStepSize (int newStepSize) {    ➂
		stepSize = newStepSize;
	}


	/**
	 * Compute the value that lies (i/n) of the way between x and y.
	 * 
	 * @param x any integer value
	 * @param y any integer value
	 * @param i an integer in the range 0..steps indicating how close to y we want to be
	 * @param steps how many steps from x to y
	 * @return an interpolated value between x and y
	 */
	private int interpolate (int x, int y, int i, int steps) {
		return (i * x + (steps-i)*y) / steps;
	}

	/**
	 * Compute a color that lies between c1 and c2.  This is the function
	 * used  to "shade" lines between the two base colors.
	 *  
	 * @param c1 any color
	 * @param c2 any colot
	 * @param i an integer in the range 0..steps indicating how close to c2 we want to be
	 * @param steps how many steps from c1 to c2
	 * @return an interpolated value between c1 and c2
	 * @return an interpolated color value.
	 */

	private Color interpolate(Color c1, Color c2, int i, int steps) {
		return new Color (interpolate(c1.getRed(), c2.getRed(), i, steps),
				interpolate(c1.getGreen(), c2.getGreen(), i, steps),
				interpolate(c1.getBlue(), c2.getBlue(), i, steps));
	}


	/**
	 * An (x,y) Cartesian coordinate.
	 * @author zeil
	 *
	 */
	private class Point {
		public double x;
		public double y;
	}

	/**
	 * Get the coordinates of a point on a circle.
	 * @param degrees The angle around the circle where we want the point.
	 * @param radius  The radius of the circle.
	 * @param center  The center of the circle.
	 * @return  the coordinates of a point on the edge of the circle at the desired angle. 
	 */
	private Point ptOnCircle (int degrees, int radius, Point center) {
		Point p = new Point();
		double theta = Math.toRadians((double)degrees);
		p.x = center.x + (double)radius * Math.cos(theta);
		p.y = center.y + (double)radius * Math.sin(theta);
		return p;
	}

	/**
	 * Draw a series of lines connecting 60 points set around
	 * a circle.
	 * 
	 * @param g the graphics device on which we are to drawn.
	 * @param d the dimension (width and height) of the available
	 *          drawing area.
	 */
    public void drawLines(Graphics g, Dimension d) {    ➃
		int dmin = (d.width < d.height) ? d.width : d.height;

		if (stepSize < 1)
			stepSize = 1;

		Point center = new Point();
		center.x = (double)d.width/2.0;
		center.y = (double)d.height/2.0;

		for (int i = 0; i < 60; ++i) {
			Point origin = ptOnCircle(6*i, dmin/2, center);
			int j = i + stepSize;
			while (j >= 60)
				j -= 60;
			while (i != j) {
				Point destination = ptOnCircle(6*j, dmin/2, center);
				g.setColor(interpolate(interpolate(colors[0], colors[1], i%30, 30),
						interpolate(colors[0], colors[1], j, 60),
						1, 2));
				g.drawLine ((int)origin.x, (int)origin.y,
						(int)destination.x, (int)destination.y);
				j += stepSize;
				while (j >= 60)
					j -= 60;
			}
		}
	}


	/**
	   * Sets the background color of a button to the indicated color.
	   * Changes the foreground to either black or white, depending on
	   * which will give more contrast against the new background.
	   * 
	   * @param button
	   * @param color
	   */
	  public void setColor(JButton button, Color color) {  ➄
	    button.setBackground(color);
	    int brightness = color.getRed() + color.getGreen() + color.getBlue(); // max of 3*255
	    if (brightness > 3*255/2) {
	        // This is a fairly bright color. Use black lettering
	        button.setForeground (Color.black);
	    } else {
	        // This is a fairly dark color. Use white lettering
	        button.setForeground (Color.white);
	    }
	}
}

import java.awt.EventQueue;
import java.awt.Graphics;

import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.BorderLayout;
import java.awt.Color;
import javax.swing.JButton;
import javax.swing.JColorChooser;
import javax.swing.JTextField;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;

public class StringArtGUI {

	private JFrame mainWindow;
	private JPanel canvas;
	private JTextField textField;
	private JTextField stepSizeIn;
	
	private StringArtModel art;
	private JButton colorButton1;

	/**
	 * Launch the application.
	 */
	public static void main(String[] args) {
		EventQueue.invokeLater(new Runnable() {
			public void run() {
				try {
					StringArtGUI window = new StringArtGUI();
					window.mainWindow.setVisible(true);
				} catch (Exception e) {
					e.printStackTrace();
				}
			}
		});
	}

	/**
	 * Create the application.
	 */
	public StringArtGUI() {
		art = new StringArtModel();
		initialize();
	}

	/**
	 * Initialize the contents of the frame.
	 */
	private void initialize() {
		mainWindow = new JFrame();
		mainWindow.setBounds(100, 100, 450, 300);
		mainWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		
		canvas = new JPanel() {
			public void paint (Graphics g) {
				super.paint(g);
				art.drawLines(g, getSize());
			}
		};
		canvas.setBackground(Color.WHITE);
		mainWindow.getContentPane().add(canvas, BorderLayout.CENTER);
		
		JPanel controlPanel = new JPanel();
		mainWindow.getContentPane().add(controlPanel, BorderLayout.SOUTH);
		
		colorButton1 = new JButton("Color 1");
		colorButton1.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				Color chosen = JColorChooser.showDialog(mainWindow, "Choose a color", 
						art.getColor(0));
				if (chosen != null) {
					art.setColor(0, chosen);
					art.setColor (colorButton1, chosen);
					canvas.repaint();
				}
			}
		});
		art.setColor(colorButton1, art.getColor(0));
		controlPanel.add(colorButton1);

		JButton colorButton2 = new JButton("Color 2");
		colorButton2.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				Color chosen = JColorChooser.showDialog(mainWindow, "Choose a color", 
						art.getColor(1));
				JButton button = (JButton)e.getSource();
				if (chosen != null) {
					art.setColor(1, chosen);
					art.setColor (button, chosen);
					canvas.repaint();
				}
			}
		});
		art.setColor(colorButton2, art.getColor(1));
		controlPanel.add(colorButton2);
		
		stepSizeIn = new JTextField();
		stepSizeIn.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				try {
		            Integer newSize = new Integer(stepSizeIn.getText());
		            art.setStepSize(newSize.intValue());
		            canvas.repaint();
		          } catch (Exception ex) {};
		        }
		});
		stepSizeIn.setText("" + art.getStepSize());
		controlPanel.add(stepSizeIn);
		stepSizeIn.setColumns(3);
		
	}

}