Edit File: tiffdither.1.html
<!-- Creator : groff version 1.18.1 --> <!-- CreationDate: Sat Feb 24 18:37:20 2007 --> <html> <head> <meta name="generator" content="groff -Thtml, see www.gnu.org"> <meta name="Content-Style" content="text/css"> <title>TIFFDITHER</title> </head> <body> <h1 align=center>TIFFDITHER</h1> <a href="#NAME">NAME</a><br> <a href="#SYNOPSIS">SYNOPSIS</a><br> <a href="#DESCRIPTION">DESCRIPTION</a><br> <a href="#OPTIONS">OPTIONS</a><br> <a href="#NOTES">NOTES</a><br> <a href="#SEE ALSO">SEE ALSO</a><br> <hr> <a name="NAME"></a> <h2>NAME</h2> <!-- INDENTATION --> <table width="100%" border=0 rules="none" frame="void" cols="2" cellspacing="0" cellpadding="0"> <tr valign="top" align="left"> <td width="8%"></td> <td width="91%"> <p>tiffdither − convert a greyscale image to bilevel using dithering</p> </td> </table> <a name="SYNOPSIS"></a> <h2>SYNOPSIS</h2> <!-- INDENTATION --> <table width="100%" border=0 rules="none" frame="void" cols="2" cellspacing="0" cellpadding="0"> <tr valign="top" align="left"> <td width="8%"></td> <td width="91%"> <p><b>tiffdither</b> [ <i>options</i> ] <i>input.tif output.tif</i></p> </td> </table> <a name="DESCRIPTION"></a> <h2>DESCRIPTION</h2> <!-- INDENTATION --> <table width="100%" border=0 rules="none" frame="void" cols="2" cellspacing="0" cellpadding="0"> <tr valign="top" align="left"> <td width="8%"></td> <td width="91%"> <p><i>tiffdither</i> converts a single channel 8-bit greyscale image to a bilevel image using Floyd-Steinberg error propagation with thresholding.</p> </td> </table> <a name="OPTIONS"></a> <h2>OPTIONS</h2> <!-- TABS --> <table width="100%" border=0 rules="none" frame="void" cols="5" cellspacing="0" cellpadding="0"> <tr valign="top" align="left"> <td width="10%"></td> <td width="2%"> <p><b>−c</b></p> </td> <td width="6%"></td> <td width="80%"> <p>Specify the compression to use for data written to the output file: <b>none</b> for no compression, <b>packbits</b> for PackBits compression, <b>lzw</b> for Lempel-Ziv & Welch compression, <b>zip</b> for Deflate compression, <b>g3</b> for CCITT Group 3 (T.4) compression, and <b>g4</b> for CCITT Group 4 (T.6) compression. By default <i>tiffdither</i> will compress data according to the value of the <i>Compression</i> tag found in the source file.</p> </td> <td width="0%"> </td> </table> <!-- INDENTATION --> <table width="100%" border=0 rules="none" frame="void" cols="2" cellspacing="0" cellpadding="0"> <tr valign="top" align="left"> <td width="17%"></td> <td width="82%"> <p>The <small>CCITT</small> Group 3 and Group 4 compression algorithms can only be used with bilevel data.</p> <!-- INDENTATION --> <p>Group 3 compression can be specified together with several T.4-specific options: <b>1d</b> for 1-dimensional encoding, <b>2d</b> for 2-dimensional encoding, and <b>fill</b> 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</b> to get 2D-encoded data with byte-aligned EOL codes.</p> <!-- INDENTATION --> <p><small>LZW</small> compression can be specified together with a <i>predictor</i> 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</b> for <small>LZW</small> compression with horizontal differencing.</p> </td> </table> <!-- TABS --> <table width="100%" border=0 rules="none" frame="void" cols="5" cellspacing="0" cellpadding="0"> <tr valign="top" align="left"> <td width="10%"></td> <td width="3%"> <p><b>−f</b></p> </td> <td width="5%"></td> <td width="80%"> <p>Specify the bit fill order to use in writing output data. By default, <i>tiffdither</i> will create a new file with the same fill order as the original. Specifying <b>−f lsb2msb</b> will force data to be written with the <i>FillOrder</i> tag set to <small>LSB2MSB ,</small> while <b>−f msb2lsb</b> will force data to be written with the <i>Fill- Order</i> tag set to <small>MSB2LSB .</small></p> </td> <td width="0%"> </td> <tr valign="top" align="left"> <td width="10%"></td> <td width="3%"> <p><b>−t</b></p> </td> <td width="5%"></td> <td width="80%"> <p>Set the threshold value for dithering. By default the threshold value is 128.</p> </td> <td width="0%"> </td> </table> <a name="NOTES"></a> <h2>NOTES</h2> <!-- INDENTATION --> <table width="100%" border=0 rules="none" frame="void" cols="2" cellspacing="0" cellpadding="0"> <tr valign="top" align="left"> <td width="8%"></td> <td width="91%"> <p>The dither algorithm is taken from the <b>tiffmedian</b>(1) program (written by Paul Heckbert).</p> </td> </table> <a name="SEE ALSO"></a> <h2>SEE ALSO</h2> <!-- INDENTATION --> <table width="100%" border=0 rules="none" frame="void" cols="2" cellspacing="0" cellpadding="0"> <tr valign="top" align="left"> <td width="8%"></td> <td width="91%"> <p><b>pal2rgb</b>(1), <b>fax2tiff</b>(1), <b>tiffinfo</b>(1), <b>tiffcp</b>(1), <b>tiff2bw</b>(1), <b>libtiff</b>(3TIFF)</p> <!-- INDENTATION --> <p>Libtiff library home page: <b>http://www.remotesensing.org/libtiff/</b></p> </td> </table> <hr> </body> </html>