aWriteStream");  #if !HAVE_LIBPNG     /* defined in environ.h and config_auto.h */     return ERROR_INT("no libpng: can't write data", procName, 0); #endif  /* !HAVE_LIBPNG */      if (!fp)         return ERROR_INT("stream not defined", procName, 0);     if (!pixa)         return ERROR_INT("pixa not defined", procName, 0);      n = pixaGetCount(pixa);     f