antdisplay.java

一个TSP问题的图形演示程序

/*
 *  This code is from the book:
 *
 *    Winder, R and Roberts, G (2000) Developing Java
 *    Software, second edition, John Wiley & Sons.
 *
 *  It is copyright (c) 2000 Russel Winder and Graham Roberts.
 */

import java.awt.* ;
import javax.swing.* ;
import SimFrameWork.Display ;
/**
 *  This class specializes Display to show an ant simulation display,
 *  using AWT/Swing graphics.
 *
 *  @version 2.0 March 1999
 *  @author Graham Roberts
 */
class AntDisplay extends Display {
  /**
   *  Initialize display. For better performance a grid is first
   *  drawn onto an off-screen image. When complete the image
   *  is copied onto the display panel in one operation.
   *
   *  @param x width of display in patches
   *  @param y height of display in patches
   *  @param size size of patch in pixels
   *  @param p JPanel used to display the graphics image
   */
  public AntDisplay(int w, int h, int size, JPanel p) {
    super(w,h) ;
    panel = p ;
    blocksize = size ;
    image = p.createImage(w*blocksize,h*blocksize) ;
    imageGraphics = image.getGraphics() ;
  }
  /**
   *  Display patch at x,y with value val.  The value of val is
   *  mapped to a colour used to display the patch.
   *
   *  @param x x position of patch.
   *  @param y y position of patch.
   *  @param val value of patch.
   */
  public void show(int x, int y, int val) {
    x *= blocksize ;
    y *= blocksize ;
    // If val is greater than zero then it represents
    // the number of wood chips on a patch.
    // If -1 then an unloaded ant.
    // If -2 then a loaded ant.
    if (val > 0) {
      val = val * 5 ;
      val = (val > 255) ? 255 : val ;
      Color clr = new Color(0,val,0) ;
      imageGraphics.setColor(clr) ;
      imageGraphics.fillRect(x,y,blocksize,blocksize) ;
    } else if (val == -1) {
      imageGraphics.setColor(ANTCOLOR) ;
      imageGraphics.fillRect(x,y,blocksize,blocksize) ;
    } else if (val == -2) {
      imageGraphics.setColor(LOADEDANTCOLOR) ;
      imageGraphics.fillRect(x,y,blocksize,blocksize) ;
    }
  }
  /**
   *  Clear the display panel and display brown as the background
   *  color.
   */
  public void clear() {
    imageGraphics.setColor(new Color(128,64,0)) ;
    imageGraphics.fillRect(0,0,width*blocksize,height*blocksize) ;
  }
  /**
   *  Show the updated image by copying it onto the display panel.
   */
  public void showGrid() {
    panel.getGraphics().drawImage(image,0,0,panel) ;
  }
  // Variables to deal with graphics.
  private JPanel panel ;
  private Graphics imageGraphics ;
  private Image image ;
  private int blocksize ;
  // Colors of ants.
  private final Color ANTCOLOR = Color.red ;
  private final Color LOADEDANTCOLOR = Color.yellow ;
}