#include "stdio.h"
#include "stdlib.h"
#include "math.h"
#include "paulslib.h"
#include "bitmaplib.h"

#define NX 1000
#define NY 1000

double a[4] = {0.0,0.2,-0.15,0.75};
double b[4] = {0.0,-0.26,0.28,0.04};
double c[4] = {0.0,0.23,0.26,-0.04};
double d[4] = {0.16,0.22,0.24,0.85};
double e[4] = {0.0,0.0,0.0,0.0};
double f[4] = {0.0,1.6,0.44,1.6};

int main(int argc,char **argv)
{
   int i,j,k;
   int n = 1000;
   int ix,iy;
   double r,x,y,xlast=0,ylast=0;
   double xmin=1e32,xmax=-1e32,ymin=1e32,ymax=-1e32,scale,xmid,ymid;
   BITMAP *image;
   BITMAP white = {255,255,255};
   BITMAP black = {0,0,0};

   if (argc < 2) {
      fprintf(stderr,"Usage: %s nsteps\n",argv[0]);
      exit(0);
   }
   n = atoi(argv[1]);

   image = CreateBitmap(NX,NY);
   EraseBitmap(image,NX,NY,white);

   for (j=0;j<2;j++) {
      for (i=0;i<n;i++) {
         r = rand() % 100;
         if (r < 10)
            k = 0;
         else if (r < 18)
            k = 1;
         else if (r < 26)
            k = 2;
         else
            k = 3;
         x = a[k] * xlast + b[k] * ylast + e[k];
         y = c[k] * xlast + d[k] * ylast + f[k];
         xlast = x;
         ylast = y;
         if (x < xmin) xmin = x;
         if (y < ymin) ymin = y;
         if (x > xmax) xmax = x;
         if (y > ymax) ymax = y;
         if (j == 1) {
            scale = MIN(NX / (xmax - xmin),NY / (ymax - ymin));
            xmid = (xmin + xmax) / 2;
            ymid = (ymin + ymax) / 2;
            ix = NX / 2 + (x - xmid) * scale;
            iy = NY / 2 + (y - ymid) * scale;
            DrawPixel(image,NX,NY,ix,iy,black);
         }
      }
   }

   WriteBitmap(stdout,image,NX,NY,2);
}