text: /* File: pixmap.h */
  
  #define BLACK   0       
  #define WHITE   255
  #define MAX_VAL 256     /* Rank of possible grey values */
  
  typedef struct
  {
    int w;                 /* Width */
    int h;                 /* Height */
    unsigned char *dat;    /* Image */
    unsigned char **im;
  }page;
  
  extern int load_pixmap(char *filename, page *iimage);
  extern void store_pixmap(char *filename, page oimage);
  
  extern void  generate_page(page *opage, int h, int w, unsigned char val);
  extern void  free_page(page ipage);
  
  