User manual for old pnm functions(3) User manual for old pnm functions(3)NAMElibpnm - libnetpbm functions to read and write PNM image files
SYNOPSIS
#include <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 *max‐
valP, 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_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 for‐
mat, 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;
extern xelval pnm_pbmmaxval;
#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).
PNM TYPES AND CONSTANTS
Each xel contains three xelvals, each of which should contain only the
values between 0 and PNM_MAXMAXVAL, inclusive. pnm_pbmmaxval is the
maxval used when a PNM program reads a PBM file. Normally it is 1;
however, for some programs, a larger value gives better results.
PNM XEL MANIPULATIONS
The PNM_GET1 macro extracts a single value from an xel, when you 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.
INITIALIZATION
pnm_init is identical to pm_init().
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_read‐
pamrow() 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 PNMformatspecification(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 descrip‐
tion of forceplain above.
MISCELLANEOUS
pnm_check() is similar to pnm_checkpam() except it works only on PNM
images.
pnm_check() is identical to ppm_check().
PNM FORMAT PROMOTION
pnm_promoteformatrow() promotes a row of xels from one maxval and for‐
mat 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.
PNM XEL MANIPULATION
pnm_whitexel() and pnm_blackxel() return a white or black xel, respec‐
tively, for the given maxval and format.
pnm_invertxel() inverts an xel.
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 ALSOLibnetpbm(1), LibnetpbmUser'sGuide(1), LibnetpbmDirectory(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.
netpbm documentation 22 July 2User manual for old pnm functions(3)
