plucky (3) libpbm.3.gz

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 forceplain);

       #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       pbm_init()  is   obsolete   (at   least   since   Netpbm   9.25   (March   2002)).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 allocated 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 returning 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   function   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, including 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, including 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_readpbmrow().

       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 positioned 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 returns *eofP false (0).  If there is no
       next  image  in  the  file,  it  returns  *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  returns  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 format.

       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(1), libppm(1), libpnm(1), pbm(1)

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