libpgm(3)libpgm(3)NAMElibpgm - 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
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
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 pgm_allocarray() 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 )
Read the header from a PGM file, filling in the rows,
cols, maxval and format variables.
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libpgm(3)libpgm(3)
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
void pgm_writepgminit( FILE* fp, int cols, int rows, gray maxval, int forceplain )
Write the header for a portable graymap file. The force-
plain 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 ALSOlibpbm(3), libppm(3), libpnm(3)AUTHOR
Copyright (C) 1989, 1991 by Tony Hansen and Jef Poskanzer.
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