Rekursive Halbierung eines Quadrats in Java

Question

Ich versuche im Grunde, ein Quadrat auf dem linken unteren Quadrat bis Null zu halbieren, dann mit Rekursion die verbleibenden Quadrate oben links, oben rechts und unten rechts zu halbieren, bis alle Quadrate gefüllt sind. Allerdings führt mein Code die untere quadratische Halbierung aus, stoppt aber nur, wenn ich die neue Zeile hinzufüge und versuche, die untere Hälfte zu halbieren. Irgendwelche Ideen, warum die Ziehung aufhört? Ich kann nicht die Zeichnung einer einfachen "+" Form nach der ersten Halbierung nach unten links zu implementieren scheinen.

package recursivepatterns; 

import java.awt.Color; 
import sedgewick.*; 

public class PersianRug { 


    public static void subDiv(double S, Color C, double x, double y) { 
     // 
     StdDraw.line(x+S/2, y, x+S/2, y+S); 
     StdDraw.line(x, y+S/2, x+S, y+S/2); 
    } 


    /** 
    * 
    * @param palette an array of Colors to choose from 
    * @param llx lower left x coordinate of this rug square 
    * @param lly lower left y coordinate of this rug square 
    * @param size width (and therefore also height) of this rug square 
    * @param north color index of the north side of this rug square 
    * @param east color index of the east side of this rug square 
    * @param south color index of the south side of this rug square 
    * @param west color index of the west side of this rug square 
    */ 

    private static void persianRug( 
      Color[] palette, 
      double llx, double lly, 
      double size, 
      int north, int east, int south, int west){ 
     // 
     int c = 0; 
     Color C = palette[c]; 

     subDiv(size,C,llx,lly); 

     if (size>0){ 
      // ll 
      persianRug(palette,llx,lly,size/2, c, c, south, west); // north and east are fixed 
      // lr 
      StdDraw.setPenColor(StdDraw.RED); 
      StdDraw.circle(0.5,0.5,size/2); // this tests that circles do in fact recursively get bigger 
      persianRug(palette,llx+size/2,lly,size/2, c, c, south, west); // this line does not work at all 

     } 
     else return; 
    } 


    public static void main(String args[]) { 
     // 
     // Leave the following line commented out, but once you 
     // have things working, uncomment it, and also uncomment 
     // the similar line at the end of this method. 
     // Uncommenting those lines will run the graphics code 
     // in double-buffering mode, so that your image will appear 
     // almost instantaneously, instead of being drawn one line 
     // at a time. 
     // 
     // Here is the line to uncomment: 
     // 
     //StdDraw.show(10); // don't forget to uncomment the other line at the end 
     // 


     // 
     // Generate a palette of colors 
     // 
     Color[] palette = { StdDraw.BLUE, StdDraw.CYAN, StdDraw.DARK_GRAY, 
       StdDraw.GRAY, StdDraw.GREEN, StdDraw.LIGHT_GRAY, 
       StdDraw.MAGENTA, StdDraw.ORANGE, StdDraw.PINK, StdDraw.RED, 
       StdDraw.WHITE, StdDraw.YELLOW }; 
     // 
     // Draw the outermost square as a special case 
     // Use color 0 for that 
     // 
     StdDraw.setPenColor(palette[0]); 
     StdDraw.line(0, 0, 1, 0); 
     StdDraw.line(1, 0, 1, 1); 
     StdDraw.line(1, 1, 0, 1); 
     StdDraw.line(0, 1, 0, 0); 


     // 
     // Kick off the recursion 
     // Lower left is point (0,0) 
     // Size of the square is 1 
     // The color index of each surrounding side is 0 
     // 
     persianRug(palette, 0, 0, 1, 0, 0, 0, 0); 
     // 
     // Also uncomment this line when you have things working 
     // to speed up the drawing: 
     // 
     //StdDraw.show(10); 
     // 
    } 

} 

Answer 1

Result of fixing the tolerance to 0.005

Paket recursivepatterns;

importieren java.awt.Color; importieren Sie sedgewick. *;

public class PersianRug {

public static int pickColor(Color[] palette, int n, int e, int s, int w) { 
    // USES MODULAR ARITHMETIC AND BOUNDS OF THE PALETTE RING TO ASSIGN A COLOR 
    if ((n+s+w+e+2)%palette.length<palette.length/2-1) 
     return (n+e+s+w+8)%palette.length; // VARYING MODULAR COLOR 
    else if ((n+s+w+e+2)%palette.length>=palette.length/2-1 && (n+s+w+e)%palette.length<palette.length-5){ 
     return palette.length-8;} // FIXED COLOR OF PALETTE 
    else 
     return 0; // "BACKGROUND" COLOR 
} 

public static void subDiv(double S, double x, double y) { 
    // DRAWS A CROSS GIVEN THE LOWER LEFT CORNER COORDINATES 
    StdDraw.line(x+S/2, y, x+S/2, y+S); // vertical 
    StdDraw.line(x, y+S/2, x+S, y+S/2); // horizontal 
} 

/** 
* 
* @param palette an array of Colors to choose from 
* @param llx lower left x coordinate of this rug square 
* @param lly lower left y coordinate of this rug square 
* @param size width (and therefore also height) of this rug square 
* @param n color index of the north side of this rug square 
* @param e color index of the east side of this rug square 
* @param s color index of the south side of this rug square 
* @param w color index of the west side of this rug square 
*/ 
private static void persianRug( 
     Color[] palette, 
     double llx, double lly, 
     double size, 
     int n, int e, int s, int w){ 
    // 
    int c = pickColor(palette,n,e,s,w); 
    StdDraw.setPenColor(palette[c]); 
    subDiv(size,llx,lly); 
    n = (n+1)%palette.length; // ITERATE THE PALETTE FOR DIFFERENT COLOR NEXT ITER 
    s = (s+1)%palette.length; // 
    e = (e+1)%palette.length; // 
    w = (w+1)%palette.length; // 

    if (size>.0025){ // THIS BOUND DICTATES HOW DETAILED AND HOW QUICKLY THE RUG IS DRAWN 
     lly = lly+size/2; // TOP LEFT 
     persianRug(palette,llx,lly,size/2, n, c, c, w); 
     llx = llx+size/2; // TOP RIGHT 
     persianRug(palette,llx,lly,size/2, n, e, c, c); 
     llx=llx-size/2; // BOTTOM LEFT 
     lly = lly-size/2; 
     persianRug(palette,llx,lly,size/2, c, c, s, w); 
     llx = llx+(size/2); // BOTTOM RIGHT 
     persianRug(palette,llx,lly,size/2, c, e, s, c); 

    } 
    else return; 
} 


public static void main(String args[]) { 
    // 
    // Leave the following line commented out, but once you 
    // have things working, uncomment it, and also uncomment 
    // the similar line at the end of this method. 
    // Uncommenting those lines will run the graphics code 
    // in double-buffering mode, so that your image will appear 
    // almost instantaneously, instead of being drawn one line 
    // at a time. 
    // 
    // Here is the line to uncomment: 
    // 
    StdDraw.show(10); // don't forget to uncomment the other line at the end 
    // 


    // 
    // Generate a palette of colors 
    Color[] palette = { StdDraw.BLACK, StdDraw.RED, StdDraw.ORANGE, 
      StdDraw.PINK, StdDraw.BLUE, StdDraw.YELLOW, 
      StdDraw.RED, StdDraw.ORANGE, StdDraw.ORANGE, StdDraw.RED, 
      StdDraw.PINK, StdDraw.RED}; 
    // 
    // Draw the outermost square as a special case 
    // Use color 0 for that 
    // 
    StdDraw.setPenColor(palette[0]); 
    StdDraw.line(0, 0, 1, 0); 
    StdDraw.line(1, 0, 1, 1); 
    StdDraw.line(1, 1, 0, 1); 
    StdDraw.line(0, 1, 0, 0); 



    // 
    // Kick off the recursion 
    // Lower left is point (0,0) 
    // Size of the square is 1 
    // The color index of each surrounding side is 0 
    // 
    persianRug(palette, 0, 0, 1, 0, 0, 0, 0); 
    // 
    // Also uncomment this line when you have things working 
    // to speed up the drawing: 
    // 
    StdDraw.show(10); 
    // 
} 

}