Manual Pages for UNIX Operating System command usage for man tiffdither

User Commands                                       tiffdither(1)



NAME
     tiffdither - convert a  grayscale  image  to  bilevel  using
     dithering

SYNOPSIS
     tiffdither [options] input.tif output.tif

DESCRIPTION
     tiffdither converts a single-channel 8-bit  grayscale  image
     to  a  bilevel image using Floyd-Steinberg error propagation
     with thresholding.

OPTIONS
     The following options are supported:

     -c              Specify a compression  scheme  to  use  when
                     writing image data:


                     -c g3                   CCITT    Group     3
                                             compression    algo-
                                             rithm.




                     -c g4                   CCITT    Group     4
                                             compression    algo-
                                             rithm.



                     -c lzw                  Lempel-Ziv and Welch
                                             algorithm.



                     -c none                 No compression.



                     -c packbits             PackBits compression
                                             algorithm.



                     -c zip                  Deflate  compression
                                             algorithm.


                     By  default,  tiffdither   compresses   data
                     according  to  the  value of the Compression



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User Commands                                       tiffdither(1)



                     tag found in the source file.


     -f              Specify the bit fill order to use  to  write
                     output  data. By default, tiffdither creates
                     a new file with the same fill order  as  the
                     original.  Specify  -f lsb2msb to force data
                     to be written with the FillOrder tag set  to
                     LSB2MSB. Specify -f msb2lsb to force data to
                     be written with the  FillOrder  tag  set  to
                     MSB2LSB.



     -t              Set the threshold value  for  dithering.  By
                     default, the threshold value is 128.



OPERANDS
     The following operands are supported:

     input.tif       The name of the input file.



     output.tif      The name of the output file.



EXTENDED DESCRIPTION
     The CCITT Group 3 and Group  4  compression  algorithms  can
     only be used with bilevel data.

     Group 3 compression can be specified together  with  several
     T.4-specific options:

     1d                      1-dimensional encoding



     2d                      2-dimensional encoding



     fill                    Force each encoded  scanline  to  be
                             zero-filled  so that the terminating
                             EOL code lies on a byte boundary.







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User Commands                                       tiffdither(1)



     Group  3-specific  options  are  specified  by  appending  a
     colon-separated  list to the g3 option. For example, specify
     -c g3:2d:fill to get 2D-encoded data with  byte-aligned  EOL
     codes.

     LZW compression can be specified together with  a  predictor
     value.  A  predictor  value of 2 causes each scanline of the
     output image to undergo horizontal differencing before being
     encoded.  A  predictor value of 1 forces each scanline to be
     encoded without differencing.

     LZW-specific options are specified  by  appending  a  colon-
     separated  list  to  the lzw option. For example, specify -c
     lzw:2 for LZW compression with horizontal differencing.

ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Availability                | image/library/libtiff       |
    |_____________________________|_____________________________|
    | Interface stability         | Uncommitted                 |
    |_____________________________|_____________________________|


SEE ALSO
     pal2rgb(1), fax2tiff(1), tiffinfo(1), tiffcp(1), tiff2bw(1),
     libtiff(3)

NOTES
     Updated by Breda McColgan, Sun Microsystems Inc., 2004.





















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