1 import javax.swing.JPanel;
  2 import java.awt.Graphics;
  3 import java.awt.*;
  4 
  5 /*
  6  * IPView.java
  7  *
  8  * Created on March 31, 2004, 5:57 PM
  9  *
 10  *  Copyright 2004 Andrew Kaluzniacki
 11  *  All rights reserved.
 12  *  http://drewk.net
 13  */
 14 
 15 /**
 16  * IPView provides a view of IPModel
 17  * @author drew
 18  */
 19 public final class IPView extends JPanel {
 20     
 21     private IPModel model;
 22     
 23     /** Creates new form IPView */
 24     public IPView() {
 25         initComponents();
 26     }
 27     
 28     /** This method is called from within the constructor to
 29      * initialize the form.
 30      * WARNING: Do NOT modify this code. The content of this method is
 31      * always regenerated by the Form Editor.
 32      */
 33     private void initComponents() {
 34 
 35         setLayout(new java.awt.BorderLayout());
 36 
 37         setBorder(new javax.swing.border.LineBorder(new java.awt.Color(0, 0, 0)));
 38     }
 39     
 40     
 41     // Variables declaration - do not modify
 42     // End of variables declaration
 43     
 44     //  http://java.sun.com/docs/books/tutorial/uiswing/14painting/practice.html
 45     
 46     protected void paintComponent(Graphics g) {
 47         super.paintComponent(g);
 48         Graphics2D g2 = (Graphics2D)g;      // in most cases (ours) this is a safe cast
 49         
 50         // get the dimensions of the JPanel so that we can scale everything properly
 51         Insets insets = getInsets();
 52         int viewWidth = getWidth() - insets.left - insets.right;
 53         int viewHeight = getHeight() - insets.top - insets.bottom;
 54         
 55         // scale the size of the model to the size of the view.
 56         // the constants are chosen for asthetics, but could be based on say
 57         // the masses of  the objects.
 58         // Note that for the view to be physiclly correct, l and x must be
 59         // correctly proportianal. ( FIXME - better explaination )
 60         
 61         int blockWidth = viewWidth/10;
 62         int blockHeight = viewHeight/10;
 63         int penMassRadius = blockHeight/2;
 64         
 65         double modelX =  0;
 66         double modelPhi = 0;
 67         int penLength = blockHeight * 3;
 68        
 69         //
 70         if (model != null) {
 71             modelX = model.getX();
 72             modelPhi = model.getPhi();
 73         }
 74         
 75         
 76         int blockX =  (int)(modelX * penLength + viewWidth/2);
 77         int blockY =  viewHeight/2;
 78         int penX =   (int)(blockX + penLength * Math.sin(modelPhi));
 79         int penY =   (int)(blockY + penLength * Math.cos(modelPhi) - blockHeight);
 80         
 81         
 82         // paint the block
 83         g2.setColor(Color.blue);
 84         g2.fill(new Rectangle(blockX - blockWidth/2, blockY - blockHeight ,blockWidth, blockHeight));
 85         
 86         
 87         // paint the pendulum mass
 88         g2.setColor(Color.green);
 89         g2.fillOval(penX-penMassRadius, penY-penMassRadius, 2*penMassRadius, 2*penMassRadius);
 90         
 91         // paint the rod
 92         g2.drawLine(blockX,blockY -blockHeight , penX, penY);
 93     }
 94     
 95     /**
 96      * associate a model with this view
 97      */    
 98     public void setModel(IPModel aModel) {
 99         model = aModel;
100     }
101     
102     /**
103      * call when a state change in the model requires an update to the view
104      */    
105     public void modelStateChanged() {
106         this.repaint();
107     }
108     
109 }
110