PGM *pgm_read(const char *file) {

  int rows = 0, cols = 0;
  unsigned char byte;
  PGM *img;
  FILE *fp;
  int ptype;
  int max;

  if(!(fp = fopen(file, "r"))) {
      fprintf(stderr, "couldn't open file\n");
      return(NULL);
  }

  // READS IN HEADER INFO

  fscanf(fp, "P%d\n", &ptype);
  fscanf(fp, "%d %d\n", &cols, &rows);
  fscanf(fp, "%d\n", &max);

  if (!(img = pgm_alloc(rows, cols))) {
    fprintf(stderr, "couldn't allocate image\n");
    return (NULL);
  }

  img->h = rows;
  img->w = cols;
  img->max = max;
  img->ptype = ptype;

  //READS PIXELS
  for (int i = 0; i < cols; ++i) {
    for (int j = 0; j < rows; ++j) {
      fread(&byte, sizeof(unsigned char), 1, fp);
      img->gpix[i * cols + j] = (float)byte / (float)img->max;
    }
  }

    fclose(fp);
  return (img);
}