tifftopnm

 

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 tifftopnm(1)                                         tifftopnm(1)
 
 
 
NAME
        tifftopnm - convert a TIFF file into a portable anymap
 
SYNOPSIS
        tifftopnm  [--alphaout={alpha-filename,-}]  [--headerdump]
        tiff-filename
 
 
DESCRIPTION
        Reads a TIFF file as input.  Produces a portable anymap as
        output.   The type of the output file depends on the input
        file - if it's black & white, generates  a  pbm  file;  if
        it's  grayscale,  generates  a  pgm file; otherwise, a ppm
        file.  The program tells you which type it is writing.
 
        This program cannot read every possible TIFF file -- there
        are  myriad  variations  of  the TIFF format.  However, it
        does understand  monochrome  and  gray  scale,  RGB,  RGBA
        (red/green/blue  with  alpha channel), CMYK (Cyan-Magenta-
        Yellow-Black ink color separation), and color palette TIFF
        files.   An  RGB file can have either single plane (inter­
        leaved) color or multiple plane format.  The program reads
        1-8  and  16  bit-per-sample  input,  the latter in either
        bigendian or littlendian encoding.  Tiff directory  infor­
        mation may also be either bigendian or littendian.
 
        One  reason this program isn't as general as TIFF programs
        often are is that it does not use  the  TIFFRGBAImageGet()
        function  of the TIFF library to read TIFF files.  Rather,
        it uses the more primitive TIFFReadScanLine() function and
        decodes it itself.
 
        There is no fundamental reason that this program could not
        read other kinds of TIFF files; the  existing  limitations
        are mainly because no one has asked for more.
 
        The  PNM  output  has  the  same maxval as the Tiff input,
        except that  if  the  Tiff  input  is  colormapped  (which
        implies  a maxval of 65535) the PNM output has a maxval of
        255.  Though this may result  in  lost  information,  such
        input  images hardly ever actually have more color resolu­
        tion than a maxval of 255 provides and people often cannot
        deal  with PNM files that have maxval > 255.  By contrast,
        a non-colormapped Tiff image that doesn't need a maxval  >
        255 doesn't have a maxval > 255, so when we see a non-col­
        ormapped maxval > 255, we take it seriously and produce  a
        matching output maxval.
 
        The  tiff-filename  argument  names  the regular file that
        contains the Tiff image.  You cannot use Standard Input or
        any  other  special  file because the Tiff library must be
        able to perform seeks on it.
 
 
OPTIONS
        --alphaout=alpha-filename
               tifftopnm creates a  PGM  (portable  graymap)  file
               containing  the  alpha  channel values in the input
               image.  If the input image doesn't contain an alpha
               channel,  the alpha-filename file contains all zero
               (transparent) alpha values.  If you  don't  specify
               --alphaout,  tifftopnm  does  not generate an alpha
               file, and if the input image has an alpha  channel,
               tifftopnm simply discards it.
 
               If  you specify - as the filename, tifftopnm writes
               the alpha output to Standard  Output  and  discards
               the image.
 
               See  pnmcomp(1) for one way to use the alpha output
               file.
 
        --headerdump
               Dump TIFF file information to stderr.  This  infor­
               mation may be useful in debugging TIFF file conver­
               sion problems.
 
        All options can be abbreviated to  their  shortest  unique
        prefix.
 
SEE ALSO
        pnmtotiff(1), pnmtotiffcmyk(1), pnmcomp(1), pnm(5)
 
AUTHOR
        Derived  by  Jef  Poskanzer from tif2ras.c, which is Copy­
        right (c) 1990 by Sun Microsystems, Inc.  Author:  Patrick
        J. Naughton (naughton@wind.sun.com).
 
 
 
                           02 April 2000              tifftopnm(1)

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