#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "ppm.h"
// from w05/tan.c
double v(double a) { double t = fabs(tan(a));  return pow(t,1/t); }
int main( int argc, char *argv[])
{
  int n; if( argc > 1) n = atoi(argv[1]);
  if( n <= 0) n = 250;
  ppm a = ppm_new(n,n);
  double xc = n/2.0, yc = n-1, scale = n/1.6;
  for( int y = 0; y < n; ++y) for( int x = 0; x < n; ++x)
  {
    double dy = y-yc, dx = x-xc, ang = atan2(dy,dx), r = scale*v(ang), d = hypot(dy,dx);
    {
      if( d <= r) { a.r[y][x] = 255; a.g[y][x] = a.b[y][x] = 0; }
      else { a.b[y][x] = a.g[y][x] = a.r[y][x] = 255; }
    }
  }
  ppm_write( a);
  return 0;
}