libpgm

Section: C Library Functions (3)
Index Return to Main Contents
 

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 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.  

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 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

libpbm(3), libppm(3), libpnm(3)  

AUTHOR

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


 

Index

NAME
SYNOPSIS
#include <pgm.h>
DESCRIPTION
TYPES AND CONSTANTS
typedef ... gray;
#define PGM_FORMAT ...
INITIALIZATION
void pgm_init( int* argcP, char* argv[] )
MEMORY MANAGEMENT
gray** pgm_allocarray( int cols, int rows )
gray* pgm_allocrow( int cols )
void pgm_freearray( gray** grays, int rows )
void pgm_freerow( gray* grayrow )
READING FILES
void pgm_readpgminit( FILE* fp, int* colsP, int* rowsP, gray* maxvalP, int* formatP )
void pgm_readpgmrow( FILE* fp, gray* grayrow, int cols, gray maxval, int format )
gray** pgm_readpgm( FILE* fp, int* colsP, int* rowsP, gray* maxvalP )
WRITING FILES
void pgm_writepgminit( FILE* fp, int cols, int rows, gray maxval, int forceplain )
void pgm_writepgmrow( FILE* fp, gray* grayrow, int cols, gray maxval, int forceplain )
void pgm_writepgm( FILE* fp, gray** grays, int cols, int rows, gray maxval, int forceplain )
SEE ALSO
AUTHOR

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Time: 20:44:43 GMT, June 11, 2022