libpgm(3)         Image Format Library C++ Reference Manual          libpgm(3)



NAME
     libpgm - functions to support portable graymap programs

SYNOPSIS
     #include <pgm.h>
     cc ... libpgm.a libpbm.a


DESCRIPTION
   TYPES AND CONSTANTS
     typedef ... gray;
     #define PGM_MAXMAXVAL ...
     extern gray pgm_pbmmaxval;

     Each gray should contain only the values between 0 and PGMMAXMAXVAL.
     pgmpbmmaxval is the maxval used when a PGM program reads a PBM file.
     Normally it is 1; however, for some programs, a larger value gives better
     results.

     #define PGM_FORMAT ...
     #define RPGM_FORMAT ...
     #define PGM_TYPE PGM_FORMAT
     int PGM_FORMAT_TYPE( int format )

     For distinguishing different file formats and types.

   INITIALIZATION
     void pgm_init( int* argcP, char* argv[] )

     All PGM programs must call this routine.

   MEMORY MANAGEMENT
     gray** pgm_allocarray( int cols, int rows )

     Allocate an array of grays.

     gray* pgm_allocrow( int cols )

     Allocate a row of the given number of grays.

     void pgm_freearray( gray** grays, int rows )

     Free the array allocated with pgmallocarray() containing the given
     number of rows.

     void pgm_freerow( gray* grayrow )

     Free a row of grays.

   READING FILES
     void pgm_readpgminit( FILE* fp, int* colsP, int* rowsP, gray* maxvalP, int* formatP )




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libpgm(3)         Image Format Library C++ Reference Manual          libpgm(3)



     Read the header from a PGM file, filling in the rows, cols, maxval and
     format variables.

     void pgm_readpgmrow( FILE* fp, gray* grayrow, int cols, gray maxval, int format )

     Read a row of grays into the grayrow array.  Format, cols, and maxval
     were filled in by pgmreadpgminit().

     gray** pgm_readpgm( FILE* fp, int* colsP, int* rowsP, gray* maxvalP )

     Read an entire graymap file into memory, returning the allocated array
     and filling in the rows, cols and maxval variables.  This function
     combines pgmreadpgminit(), pgmallocarray() and pgmreadpgmrow().

   WRITING FILES
     void pgm_writepgminit( FILE* fp, int cols, int rows, gray maxval, int forceplain )

     Write the header for a portable graymap file.  The forceplain flag forces
     a plain-format file to be written, as opposed to a raw-format one.

     void pgm_writepgmrow( FILE* fp, gray* grayrow, int cols, gray maxval, int forceplain )

     Write a row from a portable graymap.

     void pgm_writepgm( FILE* fp, gray** grays, int cols, int rows, gray maxval, int forceplain )

     Write the header and all data for a portable graymap.  This function
     combines pgmwritepgminit() and pgmwritepgmrow().

SEE ALSO
     libpbm(3), libppm(3), libpnm(3)

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





















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