1<!-- Creator : groff version 1.18.1 --> 2<!-- CreationDate: Sat Feb 24 18:37:20 2007 --> 3<html> 4<head> 5<meta name="generator" content="groff -Thtml, see www.gnu.org"> 6<meta name="Content-Style" content="text/css"> 7<title>TIFFDITHER</title> 8</head> 9<body> 10 11<h1 align=center>TIFFDITHER</h1> 12<a href="#NAME">NAME</a><br> 13<a href="#SYNOPSIS">SYNOPSIS</a><br> 14<a href="#DESCRIPTION">DESCRIPTION</a><br> 15<a href="#OPTIONS">OPTIONS</a><br> 16<a href="#NOTES">NOTES</a><br> 17<a href="#SEE ALSO">SEE ALSO</a><br> 18 19<hr> 20<a name="NAME"></a> 21<h2>NAME</h2> 22<!-- INDENTATION --> 23<table width="100%" border=0 rules="none" frame="void" 24 cols="2" cellspacing="0" cellpadding="0"> 25<tr valign="top" align="left"> 26<td width="8%"></td> 27<td width="91%"> 28<p>tiffdither − convert a greyscale image to bilevel 29using dithering</p> 30</td> 31</table> 32<a name="SYNOPSIS"></a> 33<h2>SYNOPSIS</h2> 34<!-- INDENTATION --> 35<table width="100%" border=0 rules="none" frame="void" 36 cols="2" cellspacing="0" cellpadding="0"> 37<tr valign="top" align="left"> 38<td width="8%"></td> 39<td width="91%"> 40<p><b>tiffdither</b> [ <i>options</i> ] <i>input.tif 41output.tif</i></p> 42</td> 43</table> 44<a name="DESCRIPTION"></a> 45<h2>DESCRIPTION</h2> 46<!-- INDENTATION --> 47<table width="100%" border=0 rules="none" frame="void" 48 cols="2" cellspacing="0" cellpadding="0"> 49<tr valign="top" align="left"> 50<td width="8%"></td> 51<td width="91%"> 52<p><i>tiffdither</i> converts a single channel 8-bit 53greyscale image to a bilevel image using Floyd-Steinberg 54error propagation with thresholding.</p> 55</td> 56</table> 57<a name="OPTIONS"></a> 58<h2>OPTIONS</h2> 59<!-- TABS --> 60<table width="100%" border=0 rules="none" frame="void" 61 cols="5" cellspacing="0" cellpadding="0"> 62<tr valign="top" align="left"> 63<td width="10%"></td> 64<td width="2%"> 65 66<p><b>−c</b></p> 67</td> 68<td width="6%"></td> 69<td width="80%"> 70 71<p>Specify the compression to use for data written to the 72output file: <b>none</b> for no compression, <b>packbits</b> 73for PackBits compression, <b>lzw</b> for Lempel-Ziv & 74Welch compression, <b>zip</b> for Deflate compression, 75<b>g3</b> for CCITT Group 3 (T.4) compression, and <b>g4</b> 76for CCITT Group 4 (T.6) compression. By default 77<i>tiffdither</i> will compress data according to the value 78of the <i>Compression</i> tag found in the source file.</p> 79</td> 80<td width="0%"> 81</td> 82</table> 83<!-- INDENTATION --> 84<table width="100%" border=0 rules="none" frame="void" 85 cols="2" cellspacing="0" cellpadding="0"> 86<tr valign="top" align="left"> 87<td width="17%"></td> 88<td width="82%"> 89<p>The <small>CCITT</small> Group 3 and Group 4 compression 90algorithms can only be used with bilevel data.</p> 91<!-- INDENTATION --> 92<p>Group 3 compression can be specified together with 93several T.4-specific options: <b>1d</b> for 1-dimensional 94encoding, <b>2d</b> for 2-dimensional encoding, and 95<b>fill</b> to force each encoded scanline to be zero-filled 96so that the terminating EOL code lies on a byte boundary. 97Group 3-specific options are specified by appending a 98‘‘:’’-separated list to the 99‘‘g3’’ option; e.g. <b>−c 100g3:2d:fill</b> to get 2D-encoded data with byte-aligned EOL 101codes.</p> 102<!-- INDENTATION --> 103<p><small>LZW</small> compression can be specified together 104with a <i>predictor</i> value. A predictor value of 2 causes 105each scanline of the output image to undergo horizontal 106differencing before it is encoded; a value of 1 forces each 107scanline to be encoded without differencing. LZW-specific 108options are specified by appending a 109‘‘:’’-separated list to the 110‘‘lzw’’ option; e.g. <b>−c 111lzw:2</b> for <small>LZW</small> compression with horizontal 112differencing.</p> 113</td> 114</table> 115<!-- TABS --> 116<table width="100%" border=0 rules="none" frame="void" 117 cols="5" cellspacing="0" cellpadding="0"> 118<tr valign="top" align="left"> 119<td width="10%"></td> 120<td width="3%"> 121 122<p><b>−f</b></p> 123</td> 124<td width="5%"></td> 125<td width="80%"> 126 127<p>Specify the bit fill order to use in writing output 128data. By default, <i>tiffdither</i> will create a new file 129with the same fill order as the original. Specifying 130<b>−f lsb2msb</b> will force data to be written with 131the <i>FillOrder</i> tag set to <small>LSB2MSB ,</small> 132while <b>−f msb2lsb</b> will force data to be written 133with the <i>Fill- Order</i> tag set to <small>MSB2LSB 134.</small></p> 135</td> 136<td width="0%"> 137</td> 138<tr valign="top" align="left"> 139<td width="10%"></td> 140<td width="3%"> 141 142<p><b>−r</b></p> 143</td> 144<td width="5%"></td> 145<td width="80%"> 146 147<p>Make each strip have no more than the given number of rows.</p> 148</td> 149<td width="0%"> 150</td> 151<tr valign="top" align="left"> 152<td width="10%"></td> 153<td width="3%"> 154 155<p><b>−t</b></p> 156</td> 157<td width="5%"></td> 158<td width="80%"> 159 160<p>Set the threshold value for dithering. By default the 161threshold value is 128.</p> 162</td> 163<td width="0%"> 164</td> 165</table> 166<a name="NOTES"></a> 167<h2>NOTES</h2> 168<!-- INDENTATION --> 169<table width="100%" border=0 rules="none" frame="void" 170 cols="2" cellspacing="0" cellpadding="0"> 171<tr valign="top" align="left"> 172<td width="8%"></td> 173<td width="91%"> 174<p>The dither algorithm is taken from the 175<b>tiffmedian</b>(1) program (written by Paul Heckbert).</p> 176</td> 177</table> 178<a name="SEE ALSO"></a> 179<h2>SEE ALSO</h2> 180<!-- INDENTATION --> 181<table width="100%" border=0 rules="none" frame="void" 182 cols="2" cellspacing="0" cellpadding="0"> 183<tr valign="top" align="left"> 184<td width="8%"></td> 185<td width="91%"> 186<p><b>pal2rgb</b>(1), <b>fax2tiff</b>(1), 187<b>tiffinfo</b>(1), <b>tiffcp</b>(1), <b>tiff2bw</b>(1), 188<b>libtiff</b>(3TIFF)</p> 189<!-- INDENTATION --> 190<p>Libtiff library home page: 191<b>http://www.simplesystems.org/libtiff/</b></p> 192</td> 193</table> 194<hr> 195</body> 196</html> 197