113 lines
3.3 KiB
Groff
113 lines
3.3 KiB
Groff
.\" $Id: tiffmedian.1,v 1.4 2016-09-25 20:05:52 bfriesen Exp $
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.\"
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.\" Copyright (c) 1990-1997 Sam Leffler
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.\" Copyright (c) 1991-1997 Silicon Graphics, Inc.
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.\"
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.\" Permission to use, copy, modify, distribute, and sell this software and
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.\" its documentation for any purpose is hereby granted without fee, provided
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.\" that (i) the above copyright notices and this permission notice appear in
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.\" all copies of the software and related documentation, and (ii) the names of
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.\" Sam Leffler and Silicon Graphics may not be used in any advertising or
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.\" publicity relating to the software without the specific, prior written
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.\" permission of Sam Leffler and Silicon Graphics.
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.\"
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.\" THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
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.\" EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
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.\" WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
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.\"
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.\" IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
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.\" ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
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.\" OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
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.\" WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
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.\" LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
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.\" OF THIS SOFTWARE.
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.\"
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.if n .po 0
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.TH TIFFMEDIAN 1 "November 2, 2005" "libtiff"
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.SH NAME
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tiffmedian \- apply the median cut algorithm to data in a
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.SM TIFF
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file
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.SH SYNOPSIS
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.B tiffmedian
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[
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.I options
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]
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.I input.tif
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.I output.tif
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.SH DESCRIPTION
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.I tiffmedian
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applies the median cut algorithm to an
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.SM RGB
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image in
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.I input.tif
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to generate a palette image that is written to
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.IR output.tif .
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The generated colormap has, by default, 256 entries.
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The image data is quantized by mapping each
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pixel to the closest color values in the colormap.
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.SH OPTIONS
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.TP
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.B \-c
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Specify the compression to use for data written to the output file:
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.B none
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for no compression,
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.B packbits
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for PackBits compression,
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.B lzw
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for Lempel-Ziv & Welch compression,
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and
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.B zip
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for Deflate compression.
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By default
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.I tiffmedian
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will compress data according to the value of the
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.I Compression
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tag found in the source file.
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.IP
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.SM LZW
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compression can be specified together with a
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.I predictor
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value.
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A predictor value of 2 causes
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each scanline of the output image to undergo horizontal
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differencing before it is encoded; a value
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of 1 forces each scanline to be encoded without differencing.
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LZW-specific options are specified by appending a ``:''-separated
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list to the ``lzw'' option; e.g.
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.B "\-c lzw:2"
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for
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.SM LZW
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compression with horizontal differencing.
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.TP
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.B \-C
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Specify the number of entries to use in the generated colormap.
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By default all 256 entries/colors are used.
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.TP
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.B \-f
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Apply Floyd-Steinberg dithering before selecting a colormap entry.
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.TP
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.B \-r
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Specify the number of rows (scanlines) in each strip of data
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written to the output file.
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By default,
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.I tiffmedian
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attempts to set the rows/strip
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that no more than 8 kilobytes of data appear in a strip.
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.SH NOTES
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This program is derived from Paul Heckbert's
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.I median
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program.
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.SH "SEE ALSO"
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.BR pal2rgb (1),
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.BR tiffinfo (1),
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.BR tiffcp (1),
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.BR tiffcmp (1),
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.BR libtiff (3TIFF)
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.PP
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.BR "Color Image Quantization for Frame Buffer Display",
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Paul Heckbert, SIGGRAPH proceedings, 1982, pp. 297-307.
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.PP
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Libtiff library home page:
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.BR http://www.simplesystems.org/libtiff/
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