tiffdither.1 3.8 KB

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  1. .\"
  2. .\" Copyright (c) 1990-1997 Sam Leffler
  3. .\" Copyright (c) 1991-1997 Silicon Graphics, Inc.
  4. .\"
  5. .\" Permission to use, copy, modify, distribute, and sell this software and
  6. .\" its documentation for any purpose is hereby granted without fee, provided
  7. .\" that (i) the above copyright notices and this permission notice appear in
  8. .\" all copies of the software and related documentation, and (ii) the names of
  9. .\" Sam Leffler and Silicon Graphics may not be used in any advertising or
  10. .\" publicity relating to the software without the specific, prior written
  11. .\" permission of Sam Leffler and Silicon Graphics.
  12. .\"
  13. .\" THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
  14. .\" EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
  15. .\" WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
  16. .\"
  17. .\" IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
  18. .\" ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
  19. .\" OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
  20. .\" WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
  21. .\" LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
  22. .\" OF THIS SOFTWARE.
  23. .\"
  24. .if n .po 0
  25. .TH TIFFDITHER 1 "September 20, 2005" "libtiff"
  26. .SH NAME
  27. tiffdither \- convert a greyscale image to bilevel using dithering
  28. .SH SYNOPSIS
  29. .B tiffdither
  30. [
  31. .I options
  32. ]
  33. .I input.tif
  34. .I output.tif
  35. .SH DESCRIPTION
  36. .I tiffdither
  37. converts a single channel 8-bit greyscale image to a bilevel image
  38. using Floyd-Steinberg error propagation with thresholding.
  39. .SH OPTIONS
  40. .TP
  41. .B \-c
  42. Specify the compression to use for data written to the output file:
  43. .B none
  44. for no compression,
  45. .B packbits
  46. for PackBits compression,
  47. .B lzw
  48. for Lempel-Ziv & Welch compression,
  49. .B zip
  50. for Deflate compression,
  51. .B g3
  52. for CCITT Group 3 (T.4) compression,
  53. and
  54. .B g4
  55. for CCITT Group 4 (T.6) compression.
  56. By default
  57. .I tiffdither
  58. will compress data according to the value of the
  59. .I Compression
  60. tag found in the source file.
  61. .IP
  62. The
  63. .SM CCITT
  64. Group 3 and Group 4 compression algorithms can only
  65. be used with bilevel data.
  66. .IP
  67. Group 3 compression can be specified together with several
  68. T.4-specific options:
  69. .B 1d
  70. for 1-dimensional encoding,
  71. .B 2d
  72. for 2-dimensional encoding,
  73. and
  74. .B fill
  75. to force each encoded scanline to be zero-filled so that the
  76. terminating EOL code lies on a byte boundary.
  77. Group 3-specific options are specified by appending a ``:''-separated
  78. list to the ``g3'' option; e.g.
  79. .B "\-c g3:2d:fill"
  80. to get 2D-encoded data with byte-aligned EOL codes.
  81. .IP
  82. .SM LZW
  83. compression can be specified together with a
  84. .I predictor
  85. value.
  86. A predictor value of 2 causes
  87. each scanline of the output image to undergo horizontal
  88. differencing before it is encoded; a value
  89. of 1 forces each scanline to be encoded without differencing.
  90. LZW-specific options are specified by appending a ``:''-separated
  91. list to the ``lzw'' option; e.g.
  92. .B "\-c lzw:2"
  93. for
  94. .SM LZW
  95. compression with horizontal differencing.
  96. .TP
  97. .B \-f
  98. Specify the bit fill order to use in writing output data.
  99. By default,
  100. .I tiffdither
  101. will create a new file with the same fill order as the original.
  102. Specifying
  103. .B "\-f lsb2msb"
  104. will force data to be written with the
  105. .I Fill\%Order
  106. tag set to
  107. .SM LSB2MSB ,
  108. while
  109. .B "\-f msb2lsb"
  110. will force data to be written with the
  111. .I Fill\%Order
  112. tag set to
  113. .SM MSB2LSB .
  114. .TP
  115. .B \-r
  116. Make each strip have no more than the given number of rows.
  117. .TP
  118. .B \-t
  119. Set the threshold value for dithering.
  120. By default the threshold value is 128.
  121. .SH NOTES
  122. The dither algorithm is taken from the
  123. .BR tiffmedian (1)
  124. program (written by Paul Heckbert).
  125. .SH "SEE ALSO"
  126. .BR pal2rgb (1),
  127. .BR fax2tiff (1),
  128. .BR tiffinfo (1),
  129. .BR tiffcp (1),
  130. .BR tiff2bw (1),
  131. .BR libtiff (3TIFF)
  132. .PP
  133. Libtiff library home page:
  134. .BR http://www.simplesystems.org/libtiff/