#include<stdio.h>
#include<stdlib.h>

#define SIZE 256
#define SCALE ((double)SIZE / 1024.0)

typedef struct { int x, y; } XY;
static XY points[] =
{
   {100, 900},
   {100, 500}, {600, 300}, {900, 100},
   {1000, 400}, {700, 600}, {900, 900},
   {600, 1000}, {500, 900}, {100, 900},
   {0, 0}
};

/* Interpolate between two points. */
static double Interpolate(double a, double b, double t)
{
   return a + (b - a) * t;
}

int main(int argc, char **argv)
{
   unsigned char *image = calloc(SIZE * SIZE, 1);
   int x, y, p, t;
   double ft;

   if( image == NULL )
      return printf("Out of memory\n");

   /* Draw edges. */
   for(p = 0; points[p + 1].x != 0; p += 3)
   {
      for(t = 0; t < SIZE * 4; t++)
      {
         ft = (double)t / (SIZE * 4.0);

         /* https://en.wikipedia.org/wiki/De_Casteljau%27s_algorithm */
         x = (int)
            Interpolate(
               Interpolate(
                  Interpolate(points[p].x * SCALE, points[p+1].x * SCALE, ft),
                  Interpolate(points[p+1].x * SCALE, points[p+2].x * SCALE, ft),
                  ft),
               Interpolate(
                  Interpolate(points[p+1].x * SCALE, points[p+2].x * SCALE, ft),
                  Interpolate(points[p+2].x * SCALE, points[p+3].x * SCALE, ft),
                  ft),
               ft);
         y = (int)
            Interpolate(
               Interpolate(
                  Interpolate(points[p].y * SCALE, points[p+1].y * SCALE, ft),
                  Interpolate(points[p+1].y * SCALE, points[p+2].y * SCALE, ft),
                  ft),
               Interpolate(
                  Interpolate(points[p+1].y * SCALE, points[p+2].y * SCALE, ft),
                  Interpolate(points[p+2].y * SCALE, points[p+3].y * SCALE, ft),
                  ft),
               ft);

         if( x >= 0 && x < SIZE && y >= 0 && y < SIZE )
            image[y * SIZE + x] = 1;
      }
   }

   /* Output image as PBM. */
   printf("P1\n%d %d\n", SIZE, SIZE);
   for(y = 0; y < SIZE; y++)
   {
      for(x = 0; x < SIZE; x++)
         fputs(image[y * SIZE + x] ? "0 " : "1 ", stdout);
      putchar('\n');
   }
   return 0;
}