maze.java

这是一个实现自动生成随机迷宫

/*********************************************************************************

   Creates a random maze, then solves it by finding a path from the
   upper left corner to the lower right corner.  (After doing
   one maze, it waits a while then starts over by creating a
   new random maze.)
   
   This applet is cutomizable using the following parameters in
   its <applet> tag:
   
        name            default value    meaning
       ------           ---------------  --------------------------------------
        rows                     21         number of rows in maze (must be odd)
        columns                  21         number of columns in maze (must be odd)
        border                    0         width of colored border around maze
                                              (extra space after making equal-sized
                                               rows and columns is also part of the border)
        sleepTime              5000         pause, in milliseconds between
                                               solving one maze and creating
                                               another
        speed                     3         integer between 1 and 5 specifying
                                               how fast the a maze is created
                                               and solved.  (1 is fastest.)
        wallColor             black  
        emptyColor      128 128 255
        pathColor           200 0 0      
        visitedColor  same as empty
        borderColor           white
        
    Parameter names are case sensative.  Parameters that specify
    colors can be given by one of the predefined color names
    (black, white, red, blue, green, cyan, magenta, yellow, pink
    orange, gray, lightGray, darkGray) or as an RGB color specified
    by three integers between 0 and 255.  Color names are NOT
    case sensative.

BY:  David Eck
     Department of Mathematics and Computer Science
     Hobart and William Smith Colleges
     Geneva, NY   14456
     
     E-mail:  [e-mail]
     

NOTE:  YOU CAN DO ANYTHING YOU WANT WITH THIS CODE AND APPLET, EXCEPT
       CLAIM CREDIT FOR THEM (such as by trying to copyright the code
       your self).

**************************************************************************/


import java.awt.*;

public class Maze extends java.applet.Applet implements Runnable {

    int[][] maze;  // Description of state of maze.  The value of maze[i][j]
                   // is one of the constants wallCode, pathcode, emptyCode,
                   // or visitedCode.  (Value can also be negative, temporarily,
                   // inside createMaze().)
                   //    A maze is made up of walls and corridors.  maze[i][j]
                   // is either part of a wall or part of a corridor.  A cell
                   // cell that is part of a cooridor is represented by pathCode
                   // if it is part of the current path through the maze, by
                   // visitedCode if it has already been explored without finding
                   // a solution, and by emptyCode if it has not yet been explored.

    final static int backgroundCode = 0;
    final static int wallCode = 1;
    final static int pathCode = 2;
    final static int emptyCode = 3;
    final static int visitedCode = 4;
    
       // the next six items are set up in init(), and can be specified 
       // using applet parameters

    Color[] color = new Color[5];  // colors associated with the preceding 5 constants;
    int rows = 21;          // number of rows of cells in maze, including a wall around edges
    int columns = 21;       // number of columns of cells in maze, including a wall around edges
    int border = 0;         // minimum number of pixels between maze and edge of applet
    int sleepTime = 5000;   // wait time after solving one maze before making another
    int speedSleep = 50;    // short delay between steps in making and solving maze
    
    Thread mazeThread;   // thread for creating and solving maze
    Graphics me = null;  // graphics context for applet; created in checkSize()
    
    int width = -1;   // width of applet, to be set by checkSize()
    int height = -1;  // height of applet, to be set by checkSize()

    int totalWidth;   // width of applet, minus border area (set in checkSize())
    int totalHeight;  // height of applet, minus border area (set in checkSize())
    int left;         // left edge of maze, allowing for border (set in checkSize())
    int top;          // top edge of maze, allowing for border (set in checkSize())
    
    boolean mazeExists = false;  // set to true when maze[][] is valid; used in
                                 // redrawMaze(); set to true in createMaze(), and
                                 // reset to false in run()



    Integer getIntParam(String paramName) {
          // Utility routine for reading an applet param which is an integer.
          // Returns null if there is no such param, or if the value is not
          // a legal integer.
       String param = getParameter(paramName);
       if (param == null)
          return null;
       int i;
       try {
          i = Integer.parseInt(param);
       }
       catch (NumberFormatException e) {
          return null;
       }
       return new Integer(i);
    }
    
    Color getColorParam(String paramName) {
          // Utility routine for reading an applet param which is a color.
          // Returns null if there is no such param, or if the value is not
          // a legal color.  Colors can be specified as three integers,
          // separated by spaces, giving RGB components in the range 0 to 255;
          // the standard Java color names are also acceptable.
       String param = getParameter(paramName);
       if (param == null || param.length() == 0)
          return null;
       if (Character.isDigit(param.charAt(0))) {  // try to parse RGB color
          int r=0,g=0,b=0;
          int pos=0;
          int d=0;
          int len=param.length();
          while (pos < len && Character.isDigit(param.charAt(pos)) && r < 255) {
              d = Character.digit(param.charAt(pos),10);
              r = 10*r + d;
              pos++;
          }
          if (r > 255)
             return null;
          while (pos < len && !Character.isDigit(param.charAt(pos)))
             pos++;
          if (pos >= len)
             return null;
          while (pos < len && Character.isDigit(param.charAt(pos)) && g < 255) {
              d = Character.digit(param.charAt(pos),10);
              g = 10*g + d;
              pos++;
          }
          if (g > 255)
             return null;
          while (pos < len && !Character.isDigit(param.charAt(pos)))
             pos++;
          if (pos >= len)
             return null;
          while (pos < len && Character.isDigit(param.charAt(pos)) && b < 255) {
              d = Character.digit(param.charAt(pos),10);
              b = 10*b + d;
              pos++;
          }
          if (b > 255)
             return null;
          return new Color(r,g,b);          
       }
       if (param.equalsIgnoreCase("black"))
          return Color.black;
       if (param.equalsIgnoreCase("white"))
          return Color.white;
       if (param.equalsIgnoreCase("red"))
          return Color.red;
       if (param.equalsIgnoreCase("green"))
          return Color.green;
       if (param.equalsIgnoreCase("blue"))
          return Color.blue;
       if (param.equalsIgnoreCase("yellow"))
          return Color.yellow;
       if (param.equalsIgnoreCase("cyan"))
          return Color.cyan;
       if (param.equalsIgnoreCase("magenta"))
          return Color.magenta;
       if (param.equalsIgnoreCase("pink"))
          return Color.pink;
       if (param.equalsIgnoreCase("orange"))
          return Color.orange;
       if (param.equalsIgnoreCase("gray"))
          return Color.gray;
       if (param.equalsIgnoreCase("darkgray"))
          return Color.darkGray;
       if (param.equalsIgnoreCase("lightgray"))
          return Color.lightGray;
       return null;  // param is not a legal color
    }

    public void init() {
         Integer parm;
         parm = getIntParam("rows");
         if (parm != null && parm.intValue() > 4 && parm.intValue() <= 500) {
            rows = parm.intValue();
            if (rows % 2 == 0)
               rows++;
         }
         parm = getIntParam("columns");
         if (parm != null && parm.intValue() > 4 && parm.intValue() <= 500) {
            columns = parm.intValue();
            if (columns % 2 == 0)
               columns++;
         }
         parm = getIntParam("border");
         if (parm != null && parm.intValue() > 0 && parm.intValue() <= 100)
            border = parm.intValue();
         parm = getIntParam("sleepTime");
         if (parm != null && parm.intValue() > 0)
            sleepTime = parm.intValue();
         parm = getIntParam("speed");
         if (parm != null && parm.intValue() > 0 && parm.intValue() < 6)
            switch (parm.intValue()) {
               case 1: speedSleep = 1; break;
               case 2: speedSleep = 25; break;
               case 3: speedSleep = 50; break;
               case 4: speedSleep = 100; break;
               case 5: speedSleep = 200; break;
            }