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

NAME    [Toc]    [Back]

     libpgm - functions	to support portable graymap programs

SYNOPSIS    [Toc]    [Back]

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

DESCRIPTION    [Toc]    [Back]

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

     Each gray should contain only the values between 0	and PGM_MAXMAXVAL.
     pgm_pbmmaxval 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    [Toc]    [Back]
     void pgm_init( int* argcP,	char* argv[] )

     All PGM programs must call	this routine.

   MEMORY MANAGEMENT    [Toc]    [Back]
     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 pgm_allocarray() containing the given
     number of rows.

     void pgm_freerow( gray* grayrow )

     Free a row	of grays.

   READING FILES    [Toc]    [Back]
     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 pgm_readpgminit().

     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 pgm_readpgminit(), pgm_allocarray() and pgm_readpgmrow().

   WRITING FILES    [Toc]    [Back]
     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 pgm_writepgminit() and pgm_writepgmrow().

SEE ALSO    [Toc]    [Back]

     libpbm(3),	libppm(3), libpnm(3)

AUTHOR    [Toc]    [Back]

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


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