forked from Mirrors/freeswitch
133 lines
3.7 KiB
Groff
133 lines
3.7 KiB
Groff
.\" $Id: tiffdither.1,v 1.4 2006-04-20 12:17:19 dron Exp $
|
|
.\"
|
|
.\" Copyright (c) 1990-1997 Sam Leffler
|
|
.\" Copyright (c) 1991-1997 Silicon Graphics, Inc.
|
|
.\"
|
|
.\" Permission to use, copy, modify, distribute, and sell this software and
|
|
.\" its documentation for any purpose is hereby granted without fee, provided
|
|
.\" that (i) the above copyright notices and this permission notice appear in
|
|
.\" all copies of the software and related documentation, and (ii) the names of
|
|
.\" Sam Leffler and Silicon Graphics may not be used in any advertising or
|
|
.\" publicity relating to the software without the specific, prior written
|
|
.\" permission of Sam Leffler and Silicon Graphics.
|
|
.\"
|
|
.\" THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
|
|
.\" EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
|
|
.\" WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
|
|
.\"
|
|
.\" IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
|
|
.\" ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
|
|
.\" OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
|
|
.\" WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
|
|
.\" LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
|
|
.\" OF THIS SOFTWARE.
|
|
.\"
|
|
.if n .po 0
|
|
.TH TIFFDITHER 1 "September 20, 2005" "libtiff"
|
|
.SH NAME
|
|
tiffdither \- convert a greyscale image to bilevel using dithering
|
|
.SH SYNOPSIS
|
|
.B tiffdither
|
|
[
|
|
.I options
|
|
]
|
|
.I input.tif
|
|
.I output.tif
|
|
.SH DESCRIPTION
|
|
.I tiffdither
|
|
converts a single channel 8-bit greyscale image to a bilevel image
|
|
using Floyd-Steinberg error propagation with thresholding.
|
|
.SH OPTIONS
|
|
.TP
|
|
.B \-c
|
|
Specify the compression to use for data written to the output file:
|
|
.B none
|
|
for no compression,
|
|
.B packbits
|
|
for PackBits compression,
|
|
.B lzw
|
|
for Lempel-Ziv & Welch compression,
|
|
.B zip
|
|
for Deflate compression,
|
|
.B g3
|
|
for CCITT Group 3 (T.4) compression,
|
|
and
|
|
.B g4
|
|
for CCITT Group 4 (T.6) compression.
|
|
By default
|
|
.I tiffdither
|
|
will compress data according to the value of the
|
|
.I Compression
|
|
tag found in the source file.
|
|
.IP
|
|
The
|
|
.SM CCITT
|
|
Group 3 and Group 4 compression algorithms can only
|
|
be used with bilevel data.
|
|
.IP
|
|
Group 3 compression can be specified together with several
|
|
T.4-specific options:
|
|
.B 1d
|
|
for 1-dimensional encoding,
|
|
.B 2d
|
|
for 2-dimensional encoding,
|
|
and
|
|
.B fill
|
|
to force each encoded scanline to be zero-filled so that the
|
|
terminating EOL code lies on a byte boundary.
|
|
Group 3-specific options are specified by appending a ``:''-separated
|
|
list to the ``g3'' option; e.g.
|
|
.B "\-c g3:2d:fill"
|
|
to get 2D-encoded data with byte-aligned EOL codes.
|
|
.IP
|
|
.SM LZW
|
|
compression can be specified together with a
|
|
.I predictor
|
|
value.
|
|
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.
|
|
LZW-specific options are specified by appending a ``:''-separated
|
|
list to the ``lzw'' option; e.g.
|
|
.B "\-c lzw:2"
|
|
for
|
|
.SM LZW
|
|
compression with horizontal differencing.
|
|
.TP
|
|
.B \-f
|
|
Specify the bit fill order to use in writing output data.
|
|
By default,
|
|
.I tiffdither
|
|
will create a new file with the same fill order as the original.
|
|
Specifying
|
|
.B "\-f lsb2msb"
|
|
will force data to be written with the
|
|
.I Fill\%Order
|
|
tag set to
|
|
.SM LSB2MSB ,
|
|
while
|
|
.B "\-f msb2lsb"
|
|
will force data to be written with the
|
|
.I Fill\%Order
|
|
tag set to
|
|
.SM MSB2LSB .
|
|
.TP
|
|
.B \-t
|
|
Set the threshold value for dithering.
|
|
By default the threshold value is 128.
|
|
.SH NOTES
|
|
The dither algorithm is taken from the
|
|
.BR tiffmedian (1)
|
|
program (written by Paul Heckbert).
|
|
.SH "SEE ALSO"
|
|
.BR pal2rgb (1),
|
|
.BR fax2tiff (1),
|
|
.BR tiffinfo (1),
|
|
.BR tiffcp (1),
|
|
.BR tiff2bw (1),
|
|
.BR libtiff (3TIFF)
|
|
.PP
|
|
Libtiff library home page:
|
|
.BR http://www.remotesensing.org/libtiff/
|