/*  ppmround -- make a rawbits pixmap round
    DWF  3/23/95  Version 1

    Copyright (C) 1995  David Flater.

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    If you cannot find a copy of the GNU General Public License,
    write to the Free Software Foundation, Inc., 675 Mass Ave,
    Cambridge, MA 02139, USA.

   gcc -O3 -o ppmround ppmround.c -lm
*/

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

void
usage ()
{
  fprintf (stderr, "Usage:  ppmround r g b < input > output\n");
  exit (-1);
}

void
bogus ()
{
  fprintf (stderr,
  "ppmround version 1 works ONLY on 8-bit rawbits pixmaps\n");
  fprintf (stderr,
  "with maxval = 255, and ONLY on stdin and stdout.\n");
  exit (-1);
}

int
circlep (x, y, width, height)
{
  double dx, dy;
  dx = 2.0 * fabs (x - (double)(width-1) / 2.0) / (double)width;
  dy = 2.0 * fabs (y - (double)(height-1) / 2.0) / (double)height;
  return ((dx*dx + dy*dy) <= 1.0);
}

int
main (int argc, char **argv)
{
  int width, height, maxval, x, y, r, g, b, newr, newg, newb;
  char magicnum[3], junk;
  if (argc != 4)
    usage ();
  if (sscanf (argv[1], "%d", &newr) != 1)
    usage ();
  if (sscanf (argv[2], "%d", &newg) != 1)
    usage ();
  if (sscanf (argv[3], "%d", &newb) != 1)
    usage ();
  if (fscanf (stdin, "%2s %d %d %d%c", magicnum, &width, &height,
  &maxval, &junk) != 5) {
    fprintf (stderr, "Error getting header data\n");
    bogus ();
  }
  if (strcmp (magicnum, "P6")) {
    fprintf (stderr, "Bad magic number\n");
    bogus ();
  }
  if (maxval != 255) {
    fprintf (stderr, "Maxval != 255\n");
    bogus ();
  }
  printf ("%s\n%d %d\n%d\n", magicnum, width, height, maxval);
  for (y=0;y<height;y++)
    for (x=0;x<width;x++) {
      r = getchar ();
      g = getchar ();
      b = getchar ();
      if (circlep (x, y, width, height)) {
        putchar (r);
        putchar (g);
        putchar (b);
      } else {
        putchar (newr);
        putchar (newg);
        putchar (newb);
      }
    }
  fflush (stdout);
  exit (0);
}