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Annotated edit history of pgmtoppm(1) version 2, including all changes. View license author blame.
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1 perry 1 pgmtoppm
2 !!!pgmtoppm
3 NAME
4 SYNOPSIS
5 DESCRIPTION
6 NOTE - MAXVAL
7 SEE ALSO
8 AUTHOR
9 ----
10 !!NAME
11
12
13 pgmtoppm - colorize a PGM (grayscale) image into a PGM (color) image
14 !!SYNOPSIS
15
16
17 __pgmtoppm__ ''colorspec'' [[''pgmfile'']__
18 pgmtoppm__ ''colorspec1''__-__''colorspec2''
19 [[''pgmfile'']__
20 pgmtoppm -map__ ''mapfile''
21 [[''pgmfile'']
22 !!DESCRIPTION
23
24
25 Reads a PGM as input. Produces a PPM file as output with a
26 specific color assigned to each gray value in the
27 input.
28
29
30 If you specify one color argument, black in the pgm file
31 stays black and white in the pgm file turns into the
32 specified color in the ppm file. Gray values in between are
33 linearly mapped to differing intensities of the specified
34 color.
35
36
37 If you specify two color arguments (separated by a dash),
38 then black gets mapped to the first color and white gets
39 mapped to the second and gray values in between get mapped
40 linearly (across a three dimensional space) to colors in
41 between.
42
43
44 You can specify the color in one of five ways:
45
46
47 o
48
49
50 A name, from an X11-style color names file.
51
52
53 o
54
55
56 An X11-style hexadecimal specifier: rgb:r/g/b, where r g and
57 b are each 1- to 4-digit hexadecimal numbers.
58
59
60 o
61
62
63 An X11-style decimal specifier: rgbi:r/g/b, where r g and b
64 are floating point numbers between 0 and 1.
65
66
67 o
68
69
70 For backwards compatibility, an old-X11-style hexadecimal
71 number: #rgb, #rrggbb, #rrrgggbbb, or
72 #rrrrggggbbbb.
73
74
75 o
76
77
78 For backwards compatibility, a triplet of numbers separated
79 by commas: r,g,b, where r g and b are floating point numbers
80 between 0 and 1. (This style was added before MIT came up
81 with the similar rgbi style.)
82
83
84 Also, you can specify an entire colormap with the
85 __-map__ option. The mapfile is just a __ppm__ file;
86 it can be any shape, all that matters is the colors in it
87 and their order. In this case, black gets mapped into the
88 first color in the map file, and white gets mapped to the
89 last and gray values in between are mapped linearly onto the
90 sequence of colors in between.
91 !!NOTE - MAXVAL
92
93
94 The
95 pgmtoppm__, like all Netpbm programs, can
96 accept a PBM file as if it were PGM. The maxval of this
97 image is 1, because only two gray values are needed: black
98 and white. Run this image through __pgmtoppm 0f/00/00__
99 to try to make the image black and faint red. Because the
100 output image will also have maxval 1, there is no such thing
101 as faint red. It has to be either full-on red or black.
102 __pgmtoppm__ rounds the color 0f/00/00 down to black, and
103 you get an output image that is nothing but
104 black.
105
106
107 The fix is easy: Pass the input through __pnmdepth__ on
108 the way into __pgmtoppm__ to increase its depth to
109 something that would give you the resolution you need to get
110 your desired color. In this case, __pnmdepth 16__ would
111 do it. Or spare yourself the unnecessary thinking and just
112 say __pnmdepth 255 .__
113 !!SEE ALSO
114
115
2 perry 116 pnmdepth(1), rgb3toppm(1), ppmtopgm(1),
117 ppmtorgb3(1), ppm(5),
1 perry 118 __pgm(5)__
119 !!AUTHOR
120
121
122 Copyright (C) 1991 by Jef Poskanzer.
123 ----
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