tiffdither.1.html 5.7 KB

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  7. <title>TIFFDITHER</title>
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  9. <body>
  10. <h1 align=center>TIFFDITHER</h1>
  11. <a href="#NAME">NAME</a><br>
  12. <a href="#SYNOPSIS">SYNOPSIS</a><br>
  13. <a href="#DESCRIPTION">DESCRIPTION</a><br>
  14. <a href="#OPTIONS">OPTIONS</a><br>
  15. <a href="#NOTES">NOTES</a><br>
  16. <a href="#SEE ALSO">SEE ALSO</a><br>
  17. <hr>
  18. <a name="NAME"></a>
  19. <h2>NAME</h2>
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  26. <p>tiffdither &minus; convert a greyscale image to bilevel
  27. using dithering</p>
  28. </td>
  29. </table>
  30. <a name="SYNOPSIS"></a>
  31. <h2>SYNOPSIS</h2>
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  38. <p><b>tiffdither</b> [ <i>options</i> ] <i>input.tif
  39. output.tif</i></p>
  40. </td>
  41. </table>
  42. <a name="DESCRIPTION"></a>
  43. <h2>DESCRIPTION</h2>
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  50. <p><i>tiffdither</i> converts a single channel 8-bit
  51. greyscale image to a bilevel image using Floyd-Steinberg
  52. error propagation with thresholding.</p>
  53. </td>
  54. </table>
  55. <a name="OPTIONS"></a>
  56. <h2>OPTIONS</h2>
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  63. <p><b>&minus;c</b></p>
  64. </td>
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  67. <p>Specify the compression to use for data written to the
  68. output file: <b>none</b> for no compression, <b>packbits</b>
  69. for PackBits compression, <b>lzw</b> for Lempel-Ziv &amp;
  70. Welch compression, <b>zip</b> for Deflate compression,
  71. <b>g3</b> for CCITT Group 3 (T.4) compression, and <b>g4</b>
  72. for CCITT Group 4 (T.6) compression. By default
  73. <i>tiffdither</i> will compress data according to the value
  74. of the <i>Compression</i> tag found in the source file.</p>
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  85. <p>The <small>CCITT</small> Group 3 and Group 4 compression
  86. algorithms can only be used with bilevel data.</p>
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  88. <p>Group 3 compression can be specified together with
  89. several T.4-specific options: <b>1d</b> for 1-dimensional
  90. encoding, <b>2d</b> for 2-dimensional encoding, and
  91. <b>fill</b> to force each encoded scanline to be zero-filled
  92. so that the terminating EOL code lies on a byte boundary.
  93. Group 3-specific options are specified by appending a
  94. &lsquo;&lsquo;:&rsquo;&rsquo;-separated list to the
  95. &lsquo;&lsquo;g3&rsquo;&rsquo; option; e.g. <b>&minus;c
  96. g3:2d:fill</b> to get 2D-encoded data with byte-aligned EOL
  97. codes.</p>
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  99. <p><small>LZW</small> compression can be specified together
  100. with a <i>predictor</i> value. A predictor value of 2 causes
  101. each scanline of the output image to undergo horizontal
  102. differencing before it is encoded; a value of 1 forces each
  103. scanline to be encoded without differencing. LZW-specific
  104. options are specified by appending a
  105. &lsquo;&lsquo;:&rsquo;&rsquo;-separated list to the
  106. &lsquo;&lsquo;lzw&rsquo;&rsquo; option; e.g. <b>&minus;c
  107. lzw:2</b> for <small>LZW</small> compression with horizontal
  108. differencing.</p>
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  117. <p><b>&minus;f</b></p>
  118. </td>
  119. <td width="5%"></td>
  120. <td width="80%">
  121. <p>Specify the bit fill order to use in writing output
  122. data. By default, <i>tiffdither</i> will create a new file
  123. with the same fill order as the original. Specifying
  124. <b>&minus;f lsb2msb</b> will force data to be written with
  125. the <i>FillOrder</i> tag set to <small>LSB2MSB ,</small>
  126. while <b>&minus;f msb2lsb</b> will force data to be written
  127. with the <i>Fill- Order</i> tag set to <small>MSB2LSB
  128. .</small></p>
  129. </td>
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  131. </td>
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  133. <td width="10%"></td>
  134. <td width="3%">
  135. <p><b>&minus;r</b></p>
  136. </td>
  137. <td width="5%"></td>
  138. <td width="80%">
  139. <p>Make each strip have no more than the given number of rows.</p>
  140. </td>
  141. <td width="0%">
  142. </td>
  143. <tr valign="top" align="left">
  144. <td width="10%"></td>
  145. <td width="3%">
  146. <p><b>&minus;t</b></p>
  147. </td>
  148. <td width="5%"></td>
  149. <td width="80%">
  150. <p>Set the threshold value for dithering. By default the
  151. threshold value is 128.</p>
  152. </td>
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  154. </td>
  155. </table>
  156. <a name="NOTES"></a>
  157. <h2>NOTES</h2>
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  164. <p>The dither algorithm is taken from the
  165. <b>tiffmedian</b>(1) program (written by Paul Heckbert).</p>
  166. </td>
  167. </table>
  168. <a name="SEE ALSO"></a>
  169. <h2>SEE ALSO</h2>
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  176. <p><b>pal2rgb</b>(1), <b>fax2tiff</b>(1),
  177. <b>tiffinfo</b>(1), <b>tiffcp</b>(1), <b>tiff2bw</b>(1),
  178. <b>libtiff</b>(3TIFF)</p>
  179. <!-- INDENTATION -->
  180. <p>Libtiff library home page:
  181. <b>http://www.simplesystems.org/libtiff/</b></p>
  182. </td>
  183. </table>
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