Provided by: netpbm_10.0-15_i386 bug

NAME

       pnmtotiff - convert a portable anymap into a TIFF file

SYNOPSIS

       pnmtotiff  [-none|-packbits|-lzw|-g3|-g4]  [-2d] [-fill] [-predictor n]
       [-msb2lsb|-lsb2msb]   [-rowsperstrip    n]    [-minisblack|-miniswhite]
       [-truecolor] [-color] [-indexbits 1|2|4|8] [pnmfile]

       Minimum unambiguous abbreviations of options are acceptable.

DESCRIPTION

       Reads a PNM image as input.  Produces a TIFF file as output.

       The  output  goes  to  Standard  Output, which must be a seekable file.
       That means no pipes, but any regular file should work.

OPTIONS

       By default, pnmtotiff creates a TIFF file with no compression.  This is
       your best bet most of the time.  If you want to try another compression
       scheme or tweak some of the other even  more  obscure  output  options,
       there are a number of flags to play with.

       Actually,  the  best  default would be to use LZW compression, which is
       what pnmtotiff used to do by default.  However,  the  Tiff  library  no
       longer  does  LZW  compression  due to concerns with violating Unisys's
       patent on LZW compression.

       The -none, -packbits, -lzw, -g3, -g4, -flate,  and  -adobeflat  options
       are used to override the default and set the compression scheme used in
       creating the output file.  The CCITT Group 3 and  Group  4  compression
       algorithms  can  only  be  used with bilevel data.  -lzw doesn't really
       work because the Tiff library doesn't do LZW compression.  It used  to,
       but  its developers removed the function out of concern about violating
       Unisys's patent.  This option remains in case you use  a  Tiff  library
       that  cooperates,  now or in the future.  The -2d and -fill options are
       meaningful only with Group 3 compression:  -2d  requests  2-dimensional
       encoding,  while  -fill  requests  that  each encoded scanline be zero-
       filled to a byte boundry.  The -predictor  option  is  only  meaningful
       with  LZW  compression:  a predictor value of 2 causes each scanline of
       the output image  to  undergo  horizontal  differencing  before  it  is
       encoded;  a  value  of  1  forces  each  scanline to be encoded without
       differencing.

       By default, pnmtotiff creates a TIFF file with msb-to-lsb  fill  order.
       The  -msb2lsb and -lsb2msb options are used to override the default and
       set the fill order used in creating the file.

       The fill order is the order in which pixels are packed into a  byte  in
       the  Tiff  raster, in the case that there are multiple pixels per byte.
       msb-to-lsb means that the leftmost columns go into the most significant
       bits  of  the  byte  in the Tiff image.  However, there is considerable
       confusion about the meaning of  fill  order.   Some  believe  it  means
       whether  16  bit  sample  values in the Tiff image are little-endian or
       big-endian.  This is totally erroneous (The endianness of integers in a
       Tiff  image  is  designated  by  the  image's  magic number).  However,
       ImageMagick and older Netpbm both have been  known  to  implement  that
       interpretation.  2001.09.06.

       If  the  image  does  not  have  sub-byte pixels, these options have no
       effect other than to set the value of the FILLORDER  tag  in  the  Tiff
       image (which may be useful for those programs that misinterpret the tag
       with reference to 16 bit samples).

       The -rowsperstrip option  can  be  used  to  set  the  number  of  rows
       (scanlines)  in each strip of data in the output file.  By default, the
       output file has the number of rows per strip set to a value  that  will
       ensure each strip is no more than 8 kilobytes long.

       The -minisblack and -miniswhite option force the output image to have a
       "minimum is black" or "minimum is white" photometric, respectively.  If
       you  don't  specify either, pnmtotiff uses minimum is black except when
       using Group 3 or Group 4 compression, in which case  pnmtotiff  follows
       CCITT  fax standards and uses "minimum is white."  This usually results
       in better compression and is generally preferred for bilevel coding.

       Before February 2001, pnmtotiff always produced "minimum is black," due
       to   a   bug.    In   either   case,  pnmtotiff  sets  the  photometric
       interpretation tag in the TIFF output according to which photometric is
       actually used.

       -truecolor  tells  pnmtotiff  to  produce  the  24-bit RGB form of TIFF
       output if it is producing a color TIFF  image.   Without  this  option,
       pnmtotiff  produces  a  colormapped  (paletted) 8-bit TIFF image unless
       there are more than 256 colors  (and  in  the  latter  case,  issues  a
       warning).

       The  -truecolor  option  can  prevent  pnmtotiff from making two passes
       through the input file, thus improving speed and memory usage.  See the
       section MULTIPLE PASSES.

       If  pnmtotiff  produces  a  grayscale  TIFF  image,  this option has no
       effect.

       -color tells pnmtotiff to produce a color,  as  opposed  to  grayscale,
       TIFF  image  if  the  input  is PPM, even if it contains only shades of
       gray.  Without this option, pnmtotiff produces a grayscale  TIFF  image
       if  the  input is PPM and contains only shades of gray, and at most 256
       shades.  Otherwise, it produces a color TIFF output.  For PBM  and  PGM
       input,  pnmtotiff always produces grayscale TIFF output and this option
       has no effect.

       The -color option can prevent pnmtotiff from making two passes  through
       the input file, thus improving speed and memory usage.  See the section
       MULTIPLE PASSES.

       The -indexbits option is meaningful only for a  colormapped  (paletted)
       image.  In  this  kind  of  image, the raster contains values which are
       indexes into a table of colors, with the indexes normally  taking  less
       space  that  the color description in the table. pnmtotiff can generate
       indexes of 1, 2, 4, or 8 bits. By default, it will use 8, because  many
       programs that interpret TIFF images can't handle any other width.

NOTES

       There  are  myriad  variations  of  the  TIFF  format, and this program
       generates only a few of them.  pnmtotiff creates a grayscale TIFF  file
       if  its input is a PBM (monochrome) or PGM (grayscale) file.  pnmtotiff
       also creates a grayscale file if it input is PPM (color), but there  is
       only  one  color  in the image.  If the input is a PPM (color) file and
       there are 256 colors or fewer, but more than 1, pnmtotiff  generates  a
       color palette TIFF file.  If there are more colors than that, pnmtotiff
       generates an RGB (not RGBA) single plane TIFF file.  Use  pnmtotiffcmyk
       to  generate  the  cyan-magenta-yellow-black  ink color separation TIFF
       format.

       The number of bits per sample in the TIFF output is determined  by  the
       maxval  of the PNM input.  If the maxval is less than 256, the bits per
       sample in the output is the smallest number that can encode the maxval.
       If  the  maxval  is greater than or equal to 256, there are 16 bits per
       sample in the output.

   Multiple Passes
       pnmtotiff reads the input image once if it can,  and  otherwise  twice.
       It  needs  that  second  pass  to  analyze  the colors in the image and
       generate  a  color  map  (pallette)  and  determine  if  the  image  is
       grayscale.  So the second pass only happens when the input is PPM.  And
       you can avoid it then by specifying  both  the  -truecolor  and  -color
       options.

       If  the input image is small enough to fit in your system's file cache,
       the second pass is very fast.  If not, it requires  reading  from  disk
       twice, which can be slow.

       When  the  input  is  from  a  file  that cannot be rewound and reread,
       pnmtotiff reads the entire input image into a temporary file which can,
       and works from that.  Even if it only needs one pass.

SEE ALSO

       tifftopnm(1), pnmtotiffcmyk(1), pnmdepth(1), pnm(5)

AUTHOR

       Derived  by  Jef Poskanzer from ras2tiff.c, which is Copyright (c) 1990
       by   Sun   Microsystems,   Inc.    Author:    Patrick    J.    Naughton
       (naughton@wind.sun.com).

                                24 January 2001                   pnmtotiff(1)