Provided by: libnetpbm9-dev_10.0-12.2_i386 bug

NAME

       libpgm - functions to support portable graymap (PGM) programs

SYNOPSIS

       #include <pgm.h>

       void pgm_init( int *argcP, char *argv[] );

       gray ** pgm_allocarray( int cols, int rows );

       gray * pgm_allocrow( intcols );

       void pgm_freearray( gray **grays, introws );

       void pgm_freerow( gray *grayrow);

       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 );

       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 );

       void pgm_writepgm( FILE *fp, gray **grays, int  cols,  int  rows,  gray
       maxval, int forceplain );

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

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

       typedef ... gray;

       #define PGM_MAXMAXVAL ...

       #define PGM_OVERALLMAXVAL ...

       extern gray pgm_pbmmaxval;

       #define PGM_FORMAT ...

       #define RPGM_FORMAT ...

       #define PGM_TYPE PGM_FORMAT

       #define PGM_FORMAT_TYPE(format) ...

DESCRIPTION

   TYPES AND CONSTANTS
       Each   gray   should   contain   only   the   values   between   0  and
       PGM_OVERALLMAXVAL.  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.

       PGM_OVERALLMAXVAL is the maximum value of  a  maxval  in  a  PGM  file.
       PGM_MAXMAXVAL  is  the  maximum value of a maxval in a PGM file that is
       compatible with the PGM format as it existed before April 2000.  It  is
       also the maximum value of a maxval that results in the minimum possible
       raster size for a particular image.  I.e an image with a maxval  higher
       than  PGM_MAXMAXVAL  cannot  be read or generated by old PGM processing
       programs and requires more file space.

       PGM_FORMAT is the format code  for  a  Plain  PGM  format  image  file.
       RPGM_FORMAT  is  the  format  code  for  a  Raw  PGM format image file.
       PGM_TYPE is the format type code for the PGM formats.   PGM_FORMAT_TYPE
       is a macro that generates code to compute the format type code of a PBM
       or PGM format from the format code which is its argument.

   INITIALIZATION
       All PGM programs must call pgm_init()  just  after  invocation,  before
       they process their arguments.

   MEMORY MANAGEMENT
       pgm_allocarray() allocates an array of grays.

       pgm_allocrow() allocates a row of the given number of grays.

       pgm_freearray()   frees   the  array  allocated  with  pgm_allocarray()
       containing the given number of rows.

       pgm_freerow() frees a row of grays allocated with pgm_allocrow().

   READING FILES
       If a function in this section is  called  on  a  PBM  format  file,  it
       translates  the PBM file into a PGM file on the fly and functions as if
       it were called on the equivalent PGM file.  The format  value  returned
       by  pgm_readpgminit()  is,  however, not translated.  It represents the
       actual format of the PBM file.

       pgm_readpgminit() reads the header of a PGM  file,  returning  all  the
       information  from the header and leaving the file positioned just after
       the header.

       pgm_readpgmrow() reads a row of grays into the grayrow array.   format,
       cols, and maxval are the values returned by pgm_readpgminit().

       pgm_readpgm()  reads  an  entire  PGM  image into memory, returning the
       allocated array as its return value and returning the information  from
       the   header  as  rows,  cols,  and  maxval.   This  function  combines
       pgm_readpgminit(), pgm_allocarray(), and pgm_readpgmrow().

   WRITING FILES
       pgm_writepgminit() writes the header for  a  PGM  file  and  leaves  it
       positioned just after the header.

       forceplain  is a logical value that tells pgm_writepgminit() to write a
       header for a plain PGM format file, as opposed  to  a  raw  PGM  format
       file.

       pgm_writepgmrow() writes the row grayrow to a PGM file.  For meaningful
       results, cols, maxval, and forceplain must be the same as was used with
       pgm_writepgminit().

       pgm_writepgm()  write  the  header  and all data for a PGM image.  This
       function combines pgm_writepgminit() and pgm_writepgmrow().

   MISCELLANEOUS
       pgm_nextimage() positions a PGM input file to the next image in it  (so
       that a subsequent pgm_readpgminit() reads its header).

       pgm_nextimage()  is  analogous to pbm_nextimage(), but works on PGM and
       PBM files.

       pgm_check() checks for the common file integrity error where  the  file
       is the wrong size to contain all the image data.

       pgm_check()  is  analogous  to  pbm_check(),  but  works on PGM and PBM
       files.

SEE ALSO

       libpbm(3), libppm(3), libpnm(3)

                                                                     libpgm(3)