import java.awt.*;
import java.awt.geom.*;

import javax.swing.*;

class JogDial
  extends JComponent
{
  public static final int WIDTH = 400;
  public static final int HEIGHT = 200;
  
  public static final int OFFSET = 10;
  public static final int BAR_THICKNESS = 15;
  public static final int LINE_DIFFERENCE = 7;
  
  public static final int BEAD_WIDTH = 10;
  public static final int BEAD_HEIGHT = 25;

  protected int[] values = {-2,-1,0,1,2};
  
  protected int bead_x = WIDTH/2;
  protected int bead_y = OFFSET + (BAR_THICKNESS/2);
  
  public JogDial()
  {
    super();
  }

  public Dimension getMinimumSize()
  {
    return(new Dimension(WIDTH,HEIGHT));
  }
  
  public Dimension getPreferredSize()
  {
    return(this.getMinimumSize());
  }
  
  public void drawBead(Graphics2D g2)
  {
    Rectangle bead = new Rectangle(bead_x - (this.BEAD_WIDTH/2), bead_y -(this.BEAD_HEIGHT/2), BEAD_WIDTH, BEAD_HEIGHT);
    
    g2.setColor(Color.gray);
    g2.fill(bead);
    g2.setColor(Color.black);
    g2.draw(bead);
    
  }

  
  protected void moveBeadRight()
  {
    if (bead_x < 400 - OFFSET)
      bead_x++;

    /*
    */
    Graphics g = getGraphics();
    drawBead((Graphics2D) g);  //// calls the function to draw the bead..
    g.dispose();

    // not recommended
    // repaint();

    /*
    //// repaints damaged area
    Rectangle damaged = new Rectangle(bead_x - 1 - (BEAD_WIDTH/2), bead_y - (BEAD_HEIGHT/2), 1, BEAD_HEIGHT+1);
    repaint(damaged);
    */
    
    /* 
    //// repaints new + damaged
    Rectangle bead = new Rectangle(bead_x - (this.BEAD_WIDTH/2), bead_y -(this.BEAD_HEIGHT/2), BEAD_WIDTH+1, BEAD_HEIGHT+1);
    Rectangle damaged = new Rectangle(bead_x - 1 - (BEAD_WIDTH/2), bead_y - (BEAD_HEIGHT/2), 1, BEAD_HEIGHT+1);
    repaint(bead);
    repaint(damaged);
    */
  }
  
  protected void snapBeadCenter()
  {
    Rectangle damaged = new Rectangle(bead_x - (BEAD_WIDTH/2), bead_y - (BEAD_HEIGHT/2), BEAD_WIDTH+1, BEAD_HEIGHT+1);

    bead_x = 200;

    /*
    */
    Graphics g = getGraphics();
    drawBead((Graphics2D) g);  //// calls the function to draw the bead..
    g.dispose();
    
    // not recommended
    // repaint();

    /*
    //// repaints damaged area
    repaint(damaged);
    */
    
    /*    
    //// repaints new + damaged
    Rectangle bead = new Rectangle(bead_x - (this.BEAD_WIDTH/2), bead_y -(this.BEAD_HEIGHT/2), BEAD_WIDTH+1, BEAD_HEIGHT+1);
    repaint(bead);
    repaint(damaged);
    */
  }
  
  
  
  
  
  
  
  
  public void paintComponent(Graphics g)
  {
    Graphics2D g2 = (Graphics2D) g;
    Dimension size = getSize();
    
//    Polygon p = new Polygon();
//    p.addPoint(x,y);

    Font font = new Font("Helvetica", Font.BOLD, 14);
    FontMetrics metrics = g2.getFontMetrics(font);
    
    Rectangle bar = new Rectangle(OFFSET,OFFSET,size.width-2*OFFSET,BAR_THICKNESS);

    g2.setColor(Color.black);
    g2.setFont(font);
    int segment_size = bar.width / (values.length - 1);
    for (int i=0; i<values.length; i++)
    {
      int line_x = bar.x + (i * segment_size);
      int line_low = bar.y + bar.height + this.LINE_DIFFERENCE;
      g2.drawLine(line_x, bar.y - this.LINE_DIFFERENCE, bar.x + (i * segment_size), line_low);
      
      Integer iValue = new Integer(values[i]);
      String strValue = iValue.toString();
      
      g2.drawString(strValue,line_x-(metrics.stringWidth(strValue)/2),line_low + metrics.getHeight());
    }

    g2.setColor(Color.white);
    g2.fill(bar);
    g2.setColor(Color.black);
    g2.draw(bar);
    
    drawBead(g2);
  }






}