Penguin
Recent Changes
Annotated edit history of giftopnm(1) version 1, including all changes. View license author blame.
Rev Author # Line
1 perry 1 giftopnm
2 !!!giftopnm
3 NAME
4 SYNOPSIS
5 DESCRIPTION
6 OPTIONS
7 BUGS
8 SEE ALSO
9 AUTHOR
10 LICENSE
11 ----
12 !!NAME
13
14
15 giftopnm - convert a GIF file into a portable anymap
16 !!SYNOPSIS
17
18
19 __giftopnm__
20 [[__--alphaout=__{''alpha-filename'',__-__}]
21 [[__-verbose__] [[__-comments__] [[__-image__
22 ''N''] [[''GIFfile'']
23 !!DESCRIPTION
24
25
26 Reads a GIF file for input, and outputs portable
27 anymap.
28
29
30 If you have an animated GIF file, you can extract individual
31 frames from it with __gifsicle__ and then convert those
32 using __giftopnm__.
33
34
35 A GIF image contains rectangular pixels. They all have the
36 same aspect ratio, but may not be square (it's actually
37 quite unusual for them not to be square, but it could
38 happen). The pixels of a Netpbm image are always square.
39 Because of the computational complexity to do otherwise,
40 __giftopnm__ converts a GIF image to a Netpbm image
41 pixel-for-pixel. This means if the GIF pixels are not
42 square, the Netpbm output image has the wrong aspect ratio.
43 In this case, __giftopnm__ issues an informational
44 message telling you to run __pnmscale__ to correct the
45 output.
46 !!OPTIONS
47
48
49 __--alphaout=__''alpha-filename''
50
51
52 __giftopnm__ creates a PGM (portable graymap) file
53 containing the alpha channel values in the input image. If
54 the input image doesn't contain an alpha channel, the
55 ''alpha-filename'' file contains all zero (transparent)
56 alpha values. If you don't specify __--alphaout__,
57 __giftopnm__ does not generate an alpha file, and if the
58 input image has an alpha channel, __giftopnm__ simply
59 discards it.
60
61
62 If you specify __-__ as the filename, __giftopnm__
63 writes the alpha output to Standard Output and discards the
64 image.
65
66
67 See pnmcomp(1) for one way to use the alpha output
68 file.
69
70
71 __-verbose__
72
73
74 Produce verbose output about the GIF file
75 input.
76
77
78 __-comments__
79
80
81 Only output GIF89 comment fields.
82
83
84 __-image__
85
86
87 Output the specified gif image from the input GIF archive
88 (where ''N'' is '1', '2', '20'...). Normally there is
89 only one image per file, so this option is not
90 needed.
91
92
93 All flags can be abbreviated to their shortest unique
94 prefix.
95 !!BUGS
96
97
98 This does not correctly handle the Plain Text Extension of
99 the GIF89 standard, since I did not have any example input
100 files containing them.
101 !!SEE ALSO
102
103
104 ppmtogif(1), ppmcolormask(1),
105 pnmcomp(1), gifsicle(1)
106 ppm(5).
107 !!AUTHOR
108
109
110 Copyright (c) 1993 by David Koblas
111 (koblas@netcom.com)
112 !!LICENSE
113
114
115 If you use __giftopnm__, you are using a patent on the
116 LZW compression method which is owned by Unisys, and in all
117 probability you do not have a license from Unisys to do so.
118 Unisys typically asks $5000 for a license for trivial use of
119 the patent. Unisys has never enforced the patent against
120 trivial users. The patent expires in 2003.
121
122
123 Rumor has it that IBM also owns a patent covering
124 __giftopnm__.
125
126
127 A replacement for the GIF format that does not require any
128 patents to use is the PNG format.
129 ----
This page is a man page (or other imported legacy content). We are unable to automatically determine the license status of this page.