#define DIV8(n) (((n) + 7) / 8)
#define ORDENA(a, b) {if (a > b) {int temp = a; a = b; b = temp;}}
#define LIGA_SEGURO(img, y, x) if (x < me->colunas && x >= 0 && y < me->linhas && y >= 0) me->bitmap[y][(x)/8] |= 128 >> ((x)%8);


pos_BwImage *pos_BwImage_new(int lin, int col) {
   pos_BwImage *res;
   unsigned char **bitmap;
   unsigned char *data;
   res = (pos_BwImage *)pos_malloc(sizeof(pos_BwImage));
   if (res == NULL)
      return NULL;

   bitmap = (unsigned char **)pos_malloc(sizeof(unsigned char*)*lin);
   if (bitmap == NULL) {
      pos_free(res);
      return NULL;
   }
   data = (unsigned char *)pos_calloc(lin*DIV8(col), sizeof(unsigned char));
   if (data == NULL) {
      pos_free(bitmap);
      pos_free(res);
      return NULL;
   }
   pos_BwImage_init(res, lin, col, bitmap, data);
   res->modoAlocacao = 2; // tudo mallocado
   return res;
}

pos_BwImage *pos_BwImage_init(pos_BwImage *image, int lin, int col, unsigned char **lines, unsigned char *data) {
   int i;
   image->linhas = lin;
   image->colunas = col;
   image->modoAlocacao = 0;
   image->bitmap = lines;
   for (i = 0; i < lin; i++) {
      image->bitmap[i] = data + (i*DIV8(col));
   }
   return image;
}

void pos_BwImage_drawRect(pos_BwImage *me, int x1, int y1, int x2, int y2) {
   int i;

   ORDENA(x1,x2);
   ORDENA(y1,y2);

   for (i=y1; i<y2;i++)
   {
      LIGA_SEGURO(img,i,x1);
      LIGA_SEGURO(img,i,x2);
   }
   for (i=x1; i<=x2;i++)
   {
      LIGA_SEGURO(img,y1,i);
      LIGA_SEGURO(img,y2,i);
   }
}

int main(void) {
   pos_BwImage *im1;
    pos_BwImage *im2;
    pos_BwImage *im3;
   pos_prn_Code status;

   im1 = pos_BwImage_new(1, 1);
   im2 = pos_BwImage_new(123, 345); //y=123 e x=345

   status = pos_BwImage_print(im1);
   status = pos_BwImage_print(im2);

   pos_BwImage_drawRect(im1, 0, 0, 10, 10);
   status = pos_BwImage_print(im1);
   pos_BwImage_drawRect(im2, 0, 0, 344, 124);
   status = pos_BwImage_print(im2);

   return 0;
}