NAME

       libpnm - libnetpbm functions to read and write PNM image files

SYNOPSIS

       #include <netpbm/pnm.h>

       void pnm_init( int *argcP, char *argv[] );

       xel ** pnm_allocarray( int cols, int rows);

       xel * pnm_allocrow( int cols);

       void pnm_freearray( xel **xels, int rows);

       void pnm_freerow( xel *xelrow);

       void pnm_readpnminit( FILE *fp, int *colsP, int *rowsP, xelval *maxvalP, int *formatP );

       void pnm_readpnmrow( FILE *fp, xel *xelrow, int cols, xelval maxval, int format );

       xel ** pnm_readpnm( FILE *fp, int *colsP, int *rowsP, xelval *maxvalP, int* formatP );

       void pnm_writepnminit( FILE *  fp , int cols, int rows, xelval maxval, int format, int forceplain);

       void pnm_writepnmrow( FILE *fp, xel *xelrow, int cols, xelval maxval, int format, int forceplain );

       void  pnm_writepnm(  FILE *fp, xel ** xels, int cols, int rows, xelval maxval, int format, int forceplain
       );

       void pnm_nextimage(FILE * file,
         int * const eofP);

       void pnm_check( FILE * file, const enum pm_check_type check_type, const int format, const int cols, const
       int rows, const xelval maxval, enum pm_check_code *retvalP);

       void pnm_promoteformatrow( xel *xelrow, int cols,  xelval  maxval,  int  format,  xelval  newmaxval,  int
       newformat);

       void  pnm_promoteformat(  xel  **xels,  int  cols,  xelval  maxval,  int  format,  xelval  newmaxval, int
       newformat);

       xel pnm_whitexel( xelval maxval, int format);

       xel pnm_blackxel( xelval maxval, int format);

       void pnm_invertxel( xel *x, xelval maxval, int format);

       xel pnm_backgroundxelrow( xel *xelrow, int cols, xelval maxval, int format);

       xel pnm_backgroundxel( xel **xels, int cols, int rows, xelval maxval, int format);

       typedef ... xelval;

       typedef ... xel;

       #define PNM_ASSIGN1(x,v) ...

       #define PNM_GET1(x) ...

       #define PNM_EQUAL(x,y) ...

       #define PNM_FORMAT_TYPE(format) ...

DESCRIPTION

       These library functions are part of Netpbm(1).

   TYPES AND CONSTANTS
       Each xel  contains  three  xelvals,  each  of  which  should  contain  only  the  values  between  0  and
       PNM_MAXMAXVAL, inclusive.

   XEL MANIPULATIONS
       The  PNM_GET1  macro extracts a single value from an xel, when ou know it's from a PBM or PGM file.  When
       it's from a PPM file, use PPM_GETR(), PPM_GETG(), and PPM_GETB().

       The PNM_ASSIGN1 macro assigns a single value to an xel, when you know it's from a PBM or PGM file.   When
       it's from a PPM file, use PPM_ASSIGN.

       The  PNM_EQUAL macro checks two xels for equality.  The PNM_FORMAT_TYPE macro computes a format type code
       from a format code.  The format types are PBM, PGM, PPM, and PAM.  But note that PBM, PGM, and  PPM  each
       are two different formats: a plain one and a raw one.  So there are four format types, but seven formats.
       PNM_FORMAT_TYPE does not work on the PAM format code.

       pnm_whitexel()  and  pnm_blackxel()  return  a white or black xel, respectively, for the given maxval and
       format.

       pnm_invertxel() inverts an xel.

   INITIALIZATION
       pnm_init() is obsolete (at least since Netpbm 9.25 (March 2002)).  Use pm_proginit()  instead.

       pnm_init() is identical to pm_proginit.

   MEMORY MANAGEMENT
       pnm_allocarray() allocates space for an array of xels.  pnm_freearray() frees an array space allocated by
       pnm_allocarray() or pnm_readpnm().

       pnm_allocrow() allocates space for a row of a PNM image.  pnm_freerow() frees it.

   READING PNM FILES
       pnm_readpnminit() is similar to pnm_readpaminit(),  but  reads  only  PNM  images  and  has  a  different
       parameter list.

       pnm_readpnmrow()  is  similar  to  pnm_readpamrow()  but  only  works  on  PNM images and has a different
       parameter list and returns the row as an array of xels instead of tuples.

       pnm_readpnm() is similar to pnm_readpam() except that it reads only  PNM  images  and  uses  a  different
       parameter list and returns an array of rows such that pnm_readpnmrow() would return rather than such that
       pnm_readpamrow() would return.

   WRITING FILES
       pnm_writepnminit()  is similar to pnm_writepaminit() except that it can write only a PNM header and has a
       different parameter list.

       forceplain is a binary value.  True (nonzero) means to write the image in the plain  (ASCII)  version  of
       the  selected format.  False (zero) means to write it in the raw (binary) version of the selected format.
       See PNM format specification(1).

       pnm_writepnmrow() is similar to pnm_writepamrow() except that it works only  on  PNM  images  and  has  a
       different  parameter  list and takes an array of xels instead of an array of tuples.  See the description
       of forceplain  above.

       pnm_writepnm() is similar to pnm_writepam() except that it works only  on  PNM  image,  has  a  different
       parameter  list,  and  takes  an  array  of  rows of xels instead of an array of rows of tuples.  See the
       description of forceplain above.

   FORMAT PROMOTION
       pnm_promoteformatrow() promotes a row of xels from one maxval and format to a new set.  Use this when you
       are combining multiple anymaps of different types - just take the maximum of the maxvals and the  maximum
       of the formats, and promote them all to that.

       pnm_promoteformat() promotes an entire anymap.

   MISCELLANEOUS
       pnm_nextimage()   positions   a  PNM  input  file  to  the  next  image  in  it  (so  that  a  subsequent
       pnm_readpnminit() reads its header).

       pnm_nextimage() is analogous to pbm_nextimage(), but works on PPM, PGM, and PBM files.

        pnm_check() is similar to pnm_checkpam() except it works only on PNM images.

       pnm_check() is identical to ppm_check().

       pnm_backgroundxelrow() figures out an appropriate background xel based on the row of xels  xelrow,  which
       is cols xels wide, has maxval maxval, and represents an image with format format.

       This estimate works best when the row is the top or bottom row of the image.

       pnm_backgroundxel()  does  the  same  thing  as  pnm_backgroundxelrow(),  except based on an entire image
       instead of just one row.  This tends to do a slightly better job than pnmbackgroundxelrow().

SEE ALSO

       Libnetpbm(1),  Libnetpbm  User's  Guide(1),  Libnetpbm  Directory(1),  pbm(1),  pgm(1),  ppm(1),  pam(1),
       libpbm(1), libpgm(1), libppm(1)

AUTHOR

       Copyright (C) 1989, 1991 by Tony Hansen and Jef Poskanzer.

DOCUMENT SOURCE

       This  manual  page was generated by the Netpbm tool 'makeman' from HTML source.  The master documentation
       is at

              http://netpbm.sourceforge.net/doc/libpnm.html

netpbm documentation                            08 September 2007           User manual for old pnm functions(3)