/* to run:
    gcc -O6 frac.c -lm
    stty raw ; a.out ; stty cooked

   Should sense your screen size in linux (not too big
   since xterm mouse reporting doesn't handle large
   coordinates very well).

   Commands are ',' to decrease iteration count and '.'
   to increase it.  Mouse click zooms in on that position.
   'q' quits.

 */
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <complex.h>
#include <sys/ioctl.h> // for the ioctl call.

typedef long double complex comp;
long double depth;

long double iter (comp c, long double r) {
 comp i = 0;
 while ((creal(i)*creal(i)+cimag(i)*cimag(i))<=2.0 && (r+=1.0) < depth) i =  i * i - c;
 return r;
}

void color (int c) {
 static int last=-1;
	if (c != last)
		switch (last=c) {
   	case 0: printf ("\e[0;30;7m "); return;
   	case 1: printf ("\e[1;30;7m "); return;
   	case 2: printf ("\e[0;37;7m "); return;
   	case 3: printf ("\e[0;33;7m "); return;
   	case 4: printf ("\e[0;31;7m "); return;
   	case 5: printf ("\e[1;31;7m "); return;
   	case 6: printf ("\e[1;33;7m "); return;
   	case 7: printf ("\e[1;32;7m "); return;
   	case 8: printf ("\e[0;32;7m "); return;
   	case 9: printf ("\e[0;34;7m "); return;
   	case 10: printf ("\e[1;34;7m "); return;
   	case 11: printf ("\e[0;36;7m "); return;
   	case 12: printf ("\e[1;36;7m "); return;
   	case 13: printf ("\e[0;35;7m "); return;
   	case 14: printf ("\e[1;35;7m "); return;
   	case 15: printf ("\e[1;37;7m "); return;
   	case 16: printf ("\e[0;30;7m "); return;
	default: exit(1);
		}
	else putchar (' ');
}

int main (int argc, char *argv[]) {
 long double y, x, width, height, scroll=0.0,
        a=-1.5, b=1.0, c=1.5, d=-1.0, // Upperleft, lowerleft coordinates.
        nx, ny, // New coordinate of mouse click on fractal.
        nw, nh; // New width and heigh of fractal window.
 comp i;
 long double r;
 char button, mx, my; // Mouse click positions.
 struct winsize win;


 depth =  30.0;
 printf ("\e[?9h"); // Turn on mouse reporting.
 while (1) {
 ioctl(1, TIOCGWINSZ, &win);
 width = win.ws_col;
 height = win.ws_row;
  nw = c-a;
  nh = b-d;
  printf ("\e[H\e[7m"); // Home cursor.
  for (y=b; y>d-(nh*scroll); y-=nh/((long double)height-3.0)) {
   for (x=a; x<c; x+=nw/((long double)width-1.0)) {
    r = iter(x+I*y, 0.0);
	 /*
    if      (r<depth*1.0/16.0) color(0);
    else if (r<depth*2.0/16.0) color(1);
    else if (r<depth*3.0/16.0) color(2);
    else if (r<depth*4.0/16.0) color(3);
    else if (r<depth*5.0/16.0) color(4);
    else if (r<depth*6.0/16.0) color(5);
    else if (r<depth*7.0/16.0) color(6);
    else if (r<depth*8.0/16.0) color(7);
    else if (r<depth*9.0/16.0) color(8);
    else if (r<depth*10.0/16.0)color(9);
    else if (r<depth*11.0/16.0)color(10);
    else if (r<depth*12.0/16.0)color(11);
    else if (r<depth*13.0/16.0)color(12);
    else if (r<depth*14.0/16.0)color(13);
    else if (r<depth*15.0/16.0)color(14);
    else if (r<depth*16.0/16.0)color(15);
    else                       color(16);
	 */
	 color(16*(r/depth));
   }
   printf("\r\n");
  }
  // Parse xterm mouse click.
  r = getchar();
  if (r=='r') scroll = scroll == 0.0 ? 100.0 : 0.0;
  if (r=='q') return 0;
  if (r==',') depth *=0.2;
  if (r=='.') depth *=5.0;
  if (r=='') {
   scanf("[M%c%c%c", &button, &mx, &my);
  	mx -= '!'; my -= '!';
    nx = a + ((long double)mx/(long double)width)  * nw;
    ny = b - ((long double)my/(long double)height) * nh;
   if (button == ' ') {
    nw *= 0.1;
    nh *= 0.1;
   } else {
    nw *= 0.6;
    nh *= 0.6;
   }
   a = nx-nw;
   b = ny+nh;
   c = nx+nw;
   d = ny-nh;
  }
 }
}