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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 TIFFMEDIAN 1 "November 2, 2005" "libtiff" | |
26 | .SH NAME | |
27 | tiffmedian \- apply the median cut algorithm to data in a | |
28 | .SM TIFF | |
29 | file | |
30 | .SH SYNOPSIS | |
31 | .B tiffmedian | |
32 | [ | |
33 | .I options | |
34 | ] | |
35 | .I input.tif | |
36 | .I output.tif | |
37 | .SH DESCRIPTION | |
38 | .I tiffmedian | |
39 | applies the median cut algorithm to an | |
40 | .SM RGB | |
41 | image in | |
42 | .I input.tif | |
43 | to generate a palette image that is written to | |
44 | .IR output.tif . | |
45 | The generated colormap has, by default, 256 entries. | |
46 | The image data is quantized by mapping each | |
47 | pixel to the closest color values in the colormap. | |
48 | .SH OPTIONS | |
49 | .TP | |
50 | .B \-c | |
51 | Specify the compression to use for data written to the output file: | |
52 | .B none | |
53 | for no compression, | |
54 | .B packbits | |
55 | for PackBits compression, | |
56 | .B lzw | |
57 | for Lempel-Ziv & Welch compression, | |
58 | and | |
59 | .B zip | |
60 | for Deflate compression. | |
61 | By default | |
62 | .I tiffmedian | |
63 | will compress data according to the value of the | |
64 | .I Compression | |
65 | tag found in the source file. | |
66 | .IP | |
67 | .SM LZW | |
68 | compression can be specified together with a | |
69 | .I predictor | |
70 | value. | |
71 | A predictor value of 2 causes | |
72 | each scanline of the output image to undergo horizontal | |
73 | differencing before it is encoded; a value | |
74 | of 1 forces each scanline to be encoded without differencing. | |
75 | LZW-specific options are specified by appending a ``:''-separated | |
76 | list to the ``lzw'' option; e.g. | |
77 | .B "\-c lzw:2" | |
78 | for | |
79 | .SM LZW | |
80 | compression with horizontal differencing. | |
81 | .TP | |
82 | .B \-C | |
83 | Specify the number of entries to use in the generated colormap. | |
84 | By default all 256 entries/colors are used. | |
85 | .TP | |
86 | .B \-f | |
87 | Apply Floyd-Steinberg dithering before selecting a colormap entry. | |
88 | .TP | |
89 | .B \-r | |
90 | Specify the number of rows (scanlines) in each strip of data | |
91 | written to the output file. | |
92 | By default, | |
93 | .I tiffmedian | |
94 | attempts to set the rows/strip | |
95 | that no more than 8 kilobytes of data appear in a strip. | |
96 | .SH NOTES | |
97 | This program is derived from Paul Heckbert's | |
98 | .I median | |
99 | program. | |
100 | .SH "SEE ALSO" | |
101 | .BR pal2rgb (1), | |
102 | .BR tiffinfo (1), | |
103 | .BR tiffcp (1), | |
104 | .BR tiffcmp (1), | |
105 | .BR libtiff (3TIFF) | |
106 | .PP | |
107 | .BR "Color Image Quantization for Frame Buffer Display", | |
108 | Paul Heckbert, SIGGRAPH proceedings, 1982, pp. 297-307. | |
109 | .PP | |
110 | Libtiff library home page: | |
111 | .BR http://www.remotesensing.org/libtiff/ |