180 lines
5.4 KiB
HTML
180 lines
5.4 KiB
HTML
<html>
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<head>
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<meta name="generator" content="groff -Thtml, see www.gnu.org">
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<meta name="Content-Style" content="text/css">
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<title>TIFFDITHER</title>
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</head>
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<body>
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<h1 align=center>TIFFDITHER</h1>
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<a href="#NAME">NAME</a><br>
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<a href="#SYNOPSIS">SYNOPSIS</a><br>
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<a href="#DESCRIPTION">DESCRIPTION</a><br>
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<a href="#OPTIONS">OPTIONS</a><br>
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<a href="#NOTES">NOTES</a><br>
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<a href="#SEE ALSO">SEE ALSO</a><br>
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<hr>
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<!-- Creator : groff version 1.18 -->
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<!-- CreationDate: Mon Oct 7 17:36:40 2002 -->
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<a name="NAME"></a>
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<h2>NAME</h2>
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<!-- INDENTATION -->
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<p><table width="100%" border=0 rules="none" frame="void"
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cols="2" cellspacing="0" cellpadding="0">
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<tr valign="top" align="left">
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<td width="8%"></td>
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<td width="91%">
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<p>tiffdither − convert a greyscale image to bilevel
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using dithering</p>
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</td>
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</table></p>
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<a name="SYNOPSIS"></a>
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<h2>SYNOPSIS</h2>
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<p><table width="100%" border=0 rules="none" frame="void"
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cols="2" cellspacing="0" cellpadding="0">
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<tr valign="top" align="left">
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<td width="8%"></td>
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<td width="91%">
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<p><b>tiffdither</b> [ <i>options</i> ] <i>input.tif
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output.tif</i></p>
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</td>
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</table></p>
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<a name="DESCRIPTION"></a>
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<h2>DESCRIPTION</h2>
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<p><table width="100%" border=0 rules="none" frame="void"
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cols="2" cellspacing="0" cellpadding="0">
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<tr valign="top" align="left">
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<td width="8%"></td>
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<td width="91%">
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<p><i>tiffdither</i> converts a single channel 8-bit
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greyscale image to a bilevel image using Floyd-Steinberg
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error propagation with threholding.</p>
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</td>
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</table></p>
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<a name="OPTIONS"></a>
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<h2>OPTIONS</h2>
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<!-- TABS -->
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<p><table width="100%" border=0 rules="none" frame="void"
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cols="5" cellspacing="0" cellpadding="0">
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<tr valign="top" align="left">
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<td width="10%"></td>
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<td width="2%">
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<p><b>−c</b></p>
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</td>
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<td width="6%"></td>
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<td width="80%">
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<p>Specify the compression to use for data written to the
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output file: <b>none</b> for no compression, <b>packbits</b>
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for PackBits compression, <b>lzw</b> for Lempel-Ziv &
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Welch compression, <b>zip</b> for Deflate compression,
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<b>g3</b> for CCITT Group 3 (T.4) compression, and <b>g4</b>
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for CCITT Group 4 (T.6) compression. By default
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<i>tiffdither</i> will compress data according to the value
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of the <i>Compression</i> tag found in the source file.</p>
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</td>
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<td width="0%">
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</td>
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</table></p>
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<p><table width="100%" border=0 rules="none" frame="void"
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cols="2" cellspacing="0" cellpadding="0">
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<tr valign="top" align="left">
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<td width="17%"></td>
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<td width="82%">
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<p>The <small>CCITT</small> Group 3 and Group 4 compression
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algorithms can only be used with bilevel data.</p>
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<!-- INDENTATION -->
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<p>Group 3 compression can be specified together with
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several T.4-specific options: <b>1d</b> for 1-dimensional
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encoding, <b>2d</b> for 2-dimensional encoding, and
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<b>fill</b> to force each encoded scanline to be zero-filled
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so that the terminating EOL code lies on a byte boundary.
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Group 3-specific options are specified by appending a
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‘‘:’’-separated list to the
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‘‘g3’’ option; e.g. <b>−c
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g3:2d:fill</b> to get 2D-encoded data with byte-aligned EOL
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codes.</p>
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<!-- INDENTATION -->
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<p><small>LZW</small> compression can be specified together
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with a <i>predictor</i> value. 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 of 1 forces each
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scanline to be encoded without differencing. LZW-specific
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options are specified by appending a
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‘‘:’’-separated list to the
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‘‘lzw’’ option; e.g. <b>−c
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lzw:2</b> for <small>LZW</small> compression with horizontal
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differencing.</p>
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</td>
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</table></p>
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<!-- TABS -->
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<p><table width="100%" border=0 rules="none" frame="void"
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cols="5" cellspacing="0" cellpadding="0">
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<tr valign="top" align="left">
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<td width="10%"></td>
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<td width="3%">
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<p><b>−f</b></p>
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</td>
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<td width="5%"></td>
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<td width="80%">
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<p>Specify the bit fill order to use in writing output
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data. By default, <i>tiffdither</i> will create a new file
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with the same fill order as the original. Specifying
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<b>−f lsb2msb</b> will force data to be written with
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the FillOrder tag set to <small>LSB2MSB ,</small> while
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<b>−f msb2lsb</b> will force data to be written with
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the FillOrder tag set to <small>MSB2LSB .</small></p>
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</td>
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<td width="0%">
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</td>
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<tr valign="top" align="left">
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<td width="10%"></td>
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<td width="3%">
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<p><b>−t</b></p>
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</td>
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<td width="5%"></td>
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<td width="80%">
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<p>Set the threshold value for dithering. By default the
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threshold value is 128.</p>
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</td>
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<td width="0%">
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</td>
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</table></p>
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<a name="NOTES"></a>
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<h2>NOTES</h2>
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<!-- INDENTATION -->
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<p><table width="100%" border=0 rules="none" frame="void"
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cols="2" cellspacing="0" cellpadding="0">
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<tr valign="top" align="left">
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<td width="8%"></td>
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<td width="91%">
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<p>The dither algorithm is taken from the
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<i>tiffmedian</i>(1) program (written by Paul Heckbert).</p>
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</td>
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</table></p>
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<a name="SEE ALSO"></a>
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<h2>SEE ALSO</h2>
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<!-- INDENTATION -->
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<p><table width="100%" border=0 rules="none" frame="void"
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cols="2" cellspacing="0" cellpadding="0">
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<tr valign="top" align="left">
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<td width="8%"></td>
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<td width="91%">
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<p><i>pal2rgb</i>(1), <i>fax2tiff</i>(1),
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<i>tiffinfo</i>(1), <i>tiffcp</i>(1), <i>tiff2bw</i>(1),
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<i>libtiff</i>(3)</p>
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</td>
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</table></p>
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<hr>
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</body>
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</html>
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