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User manual for	old pbm	funLibrary3FunctioUseramanual for old pbm functions(3)

NAME
       libpbm -	libnetpbm functions to read and	write PBM image	files

SYNOPSIS
       #include	<netpbm/pbm.h>

       bit **pbm_allocarray(int	cols,  int rows);

       bit *pbm_allocrow(int cols);

       pbm_freearray(bit **bits, int rows);

       pbm_freerow(bit *bitrow);

       void pbm_readpbminit(FILE * fp, int *colsP, int *rowsP, int *formatP);

       void pbm_readpbmrow(FILE	* fp, bit *bitrow, int cols, int format);

       void   pbm_readpbmrow_packed(FILE   *   fp,   unsigned	char  *	 const
       packed_bits, const int cols, const int format);

       void bit** pbm_readpbm(FILE * fp, int *colsP, int *rowsP);

       void pbm_writepbminit(FILE * fp,	int cols, int rows, int	forceplain);

       void pbm_writepbmrow(FILE * fp, bit *bitrow, int	cols, int forceplain);

       void  pbm_writepbmrow_packed(FILE  *  fp,   unsigned   char   *	 const
       packed_bits, const int cols, const int forceplain);

       void pbm_writepbm(FILE *	fp, bit	**bits,	int cols, int rows, int	force-
       plain);

       #define pbm_packed_bytes(cols) ...

       void pbm_nextimage( FILE	*file, int * const eofP);

       void pbm_check( FILE * file, const enum pm_check_type check_type, const
       int  format, const int cols, const int rows, enum pm_check_code * const
       retval);

DESCRIPTION
       These library functions are part	of Netpbm(1).

   TYPES AND CONSTANTS
       typedef ... bit;

       #define PBM_WHITE ...

       #define PBM_BLACK ...

       Each bit	should contain only the	values of PBM_WHITE or PBM_BLACK.

       #define PBM_FORMAT ...

       #define RPBM_FORMAT ...

       #define PBM_TYPE	PBM_FORMAT

       #define PBM_FORMAT_TYPE(f) ...

       These are for distinguishing different file formats and types.

   INITIALIZATION
       pbm_init() is obsolete (at least	since Netpbm 9.25 (March 2002)).   Use
       pm_proginit() <libpm.html#initialization>  instead.

       pbm_init() is identical to pm_proginit.

   MEMORY MANAGEMENT
       pbm_allocarray()	 allocates an array of bits.  pbm_allocrow() allocates
       a row of	the given number of bits.  pbm_freearray() frees the array al-
       located	with  pbm_allocarray()	containing  the	 given number of rows.
       pbm_freerow() frees a row of bits.

   READING PBM IMAGE FILES
       pbm_readpbminit() reads the header from a PBM  image  in	 a  PBM	 file,
       filling in the rows, cols and format variables.	pbm_readpbmrow() reads
       a row of	bits into the bitrow array.  Format and	cols were filled in by
       pbm_readpbminit().

       pbm_readpbmrow_packed()	is like	pbm_readpbmrow() except	instead	of re-
       turning a bits array, it	returns	an array packed_bits of	bytes with the
       pixels of the image row packed into them.  The pixels are in order from
       left to right across the	row and	from the beginning of the array	to the
       end.   Within  a	 byte, the bits	are in order from the most significant
       bit to the least	significant bit.  If the number	of pixels in  the  row
       is  not	a multiple of 8, the last byte returned	is padded on the least
       significant bit side with undefined bits.  White	is  represented	 by  a
       PBM_WHITE bit; black by PBM_BLACK.

       pbm_readpbm()  reads  an	 entire	bitmap file into memory, returning the
       allocated array and filling in the rows and cols	variables.  This func-
       tion combines pbm_readpbminit(),	pbm_allocarray() and pbm_readpbmrow().

       pbm_readpbminit()  and  pbm_readpbm abort the program with a message to
       Standard	Error if the PBM image header is not syntactically valid,  in-
       cluding	if  it	contains  a number too large to	be processed using the
       system's	normal data structures (to wit,	a number that won't fit	in a C
       'int').

       ppm_readppminit()  and  ppm_readppm abort the program with a message to
       Standard	Error if the PPM image header is not syntactically valid,  in-
       cluding	if  it	contains  a number too large to	be processed using the
       system's	normal data structures (to wit,	a number that won't fit	in a C
       'int').

   WRITING PBM IMAGE FILES
       pbm_writepbminit()  writes  the	header	for a PBM image	in a PBM file.
       forceplain is a boolean value specifying	that  a	 plain	format	(text)
       file  to	 be  written,  as  opposed  to	a  raw	format	(binary)  one.
       pbm_writepbmrow() writes	a row to a PBM file.  pbm_writepbmrow_packed()
       is  the	same  as  pbm_writepbmrow()  except that you supply the	row to
       write as	an array of bytes packed with bits instead of as a bits	array.
       The format of packed_bits  is the same as that returned by pbm_readpbm-
       row().

       pbm_writepbm() writes the header	and all	data for a PBM image to	a  PBM
       file.  This function combines pbm_writepbminit()	and pbm_writepbmrow().

   MISCELLANEOUS
       pbm_nextimage()	positions a PBM	input file to the next image in	it (so
       that a subsequent pbm_readpbminit() reads its header).

       Immediately before a call to pbm_nextimage(), the file  must  be	 posi-
       tioned  either  at  its	beginning (i.e.	nothing	has been read from the
       file yet) or just after an image	(i.e. as left  by  a  pbm_readpbmrow()
       of the last row in the image).

       Note  that  in the raw PNM and PAM format, the next image always	starts
       immediately after the previous image,  so  all  pbm_nextimage()	really
       does is test whether there is a next image or the file is positioned at
       end-of-file.  In	plain PNM, though, there may be	 white	space  between
       images.

       If  pbm_nextimage()   successfully  positions to	the next image,	it re-
       turns *eofP false (0).  If there	is no next image in the	file,  it  re-
       turns  *eofP  true .  If	it can't position or determine the file	status
       because of a file error,	it throws an error <liberror.html#error> .

       pbm_check() checks for the common file integrity	error where  the  file
       is  the	wrong size to contain all the image data.  pbm_check() assumes
       the file	is positioned after an image header (as	 if  pbm_readpbminit()
       was the last operation on the file).  It	checks the file	size to	see if
       the number of bytes left	in the file are	the number required to contain
       the  image  raster.   If	 the file is too short,	pbm_check() causes the
       program t throws	an error <liberror.html#error> .   Otherwise,  it  re-
       turns   one   of	  the  following  values  (enumerations	 of  the  enum
       pm_check_code type) as *retval:

       PM_CHECK_OK
	      The file's size is exactly what is required to  hold  the	 image
	      raster.

       PM_CHECK_UNKNOWN_TYPE
	      format  is  not  a format	whose size pbm_check() can anticipate.
	      The only format with which pbm_check() can deal is raw PBM  for-
	      mat.

       PM_CHECK_TOO_LONG
	      The  file	 is  longer  than  it needs to be to contain the image
	      raster.  The extra data might be another image.

       PM_CHECK_UNCHECKABLE
	      The file is not a	kind that has a	predictable size, so there  is
	      no  simple  way for pbm_check() to know if it is the right size.
	      Only a regular file has predictable size.	 A pipe	 is  a	common
	      example of a file	that does not.

       check_type  must	have the value PM_CHECK_BASIC  (an enumerated value of
       the  pm_check_type  enumerated  type).	Otherwise,   the   effect   of
       pbm_check() is unpredictable.  This argument exists for future backward
       compatible expansion of the function of pbm_check().

SEE ALSO
       libpgm(3), libppm(3), libpnm(3),	pbm(5)

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

DOCUMENT SOURCE
       This manual page	was generated by the Netpbm tool 'makeman'  from  HTML
       source.	The master documentation is at

	      http://netpbm.sourceforge.net/doc/libpbm.html

netpbm documentation	       8 SeptemberUser7manual for old pbm functions(3)

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | AUTHOR | DOCUMENT SOURCE

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