Munching squares

Munching squares is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

Render a graphical pattern where each pixel is colored by the value of 'x xor y' from a color table.

C

<lang c>#include <stdlib.h>

1. include <stdio.h>

int main(void) {

 const int width = 512, height = 512;
 unsigned int i, x, y;
 unsigned char color_table[256][3];
 for (i = 0; i < 256; ++i) {
   color_table[i][0] = 255 - i;  /* red */
   color_table[i][1] = i / 2;    /* green */
   color_table[i][2] = i;        /* blue */
 }
 FILE *fp = fopen("xor_pattern.ppm", "wb");
 (void) fprintf(fp, "P6\n%d %d\n255\n", width, height);
 for (y = 0; y < height; ++y) {
   for (x = 0; x < width; ++x) {
     (void) fwrite(color_table[(x ^ y) & 0xFF], 1, 3, fp);
   }
 }
 (void) fclose(fp);
 return EXIT_SUCCESS;

}</lang>

Java

This example will repeat the pattern if you expand the window. <lang java>import java.awt.Color; import java.awt.Graphics;

import javax.swing.JFrame; import javax.swing.JPanel;

public class XorPattern extends JFrame{

   private JPanel xorPanel;

   public XorPattern(){
       xorPanel = new JPanel(){
           @Override
           public void paint(Graphics g) {
               for(int y = 0; y < XorPattern.this.xorPanel.getHeight();y++){
                   for(int x = 0; x < XorPattern.this.xorPanel.getWidth();x++){
                       g.setColor(new Color(0, (x ^ y) % 256, 0));
                       g.drawLine(x, y, x, y);
                   }
               }
           }
       };
       add(xorPanel);
       setSize(300, 300);
       setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
       setVisible(true);
   }

   public static void main(String[] args){
       new XorPattern();
   }

}</lang>

Mathematica

<lang Mathematica> ListDensityPlot[

Table[Table[
  FromDigits[BitXor[IntegerDigits[x, 2, 8], IntegerDigits[y, 2, 8]], 
   2], {x, 0, 255}], {y, 0, 255}]]

</lang>

Output #1:

<lang Mathematica> ArrayPlot[Array[BitXor, {511, 511}]] </lang>

Output #2:

OCaml

<lang ocaml>open Graphics

let () =

 open_graph "";
 resize_window 256 256;
 for y = 0 to pred (size_y()) do
   for x = 0 to pred (size_x()) do
     let v = (x lxor y) land 0xFF in
     set_color (rgb v (255 - v) 0);
     plot x y
   done;
 done;
 ignore(read_key())</lang>

Run with:

$ ocaml graphics.cma xor_pattern.ml

Output: