1Pgmramp User Manual(0)                                  Pgmramp User Manual(0)
2
3
4

NAME

6       pgmramp - generate a grayscale ramp
7
8

SYNOPSIS

10       pgmramp  {-lr|-tb|-rectangle|-ellipse|-diagonal} [-maxval=maxval] width
11       height
12
13       All options can be abbreviated to their shortest  unique  prefix.   You
14       may use two hyphens instead of one to designate an option.  You may use
15       either white space or an equals sign between an  option  name  and  its
16       value.
17
18

DESCRIPTION

20       This program is part of Netpbm(1).
21
22       Generates  a  graymap of the specified size containing a black-to-white
23       ramp.  These ramps are useful for multiplying with other images,  using
24       pamarith.
25
26       The  ramp  is linear in brightness, not intensity.  I.e. the gamma-cor‐
27       rected sample values in the PGM rise linearly with  distance  from  the
28       corner of the image.  If you want a ramp that is linear in light inten‐
29       sity, use pnmgamma with pgmramp.
30
31       Options let you choose the shape of the ramp  (left  to  right,  inside
32       out,  etc.).  You can use pamflip to get more shapes.  For example, the
33       -lr option gives you a left to right ramp and
34
35           $ pgmramp -lr 100 100 | pamflip -lr
36
37
38       gives you a right to left ramp.
39
40       To generate a simple ramp of all the values from 0 to maxval,  and  not
41       necessarily a graphic image, use pamseq(1).
42
43       ppmrainbow  does something similar to what pgmramp does, but for color.
44       The image fades between two colors of your choice.
45
46
47

OPTIONS

49       In addition to the options common to all programs  based  on  libnetpbm
50       (most notably -quiet, see
51        Common  Options  ⟨index.html#commonoptions⟩  ), pgmramp recognizes the
52       following command line options:
53
54       You must specify exactly one of the ramp type options.
55
56
57
58       -lr    A left to right ramp.  Black on the left; white on the right.
59
60
61       -tb    A top to bottom ramp.  Black on top; white on the bottom.
62
63
64       -rectangle
65              An outside-in rectangular ramp.  It is black  around  the  edges
66              and white in the center.
67
68
69       -ellipse
70              An  outside-in elliptical ramp.  It is black around the edge and
71              white in the center.
72
73
74       -diagonal
75              A ramp from top left corner diagonally  down  to  bottom  right.
76              Black at the top left; white at the bottom right.
77
78              This option was new in Netpbm 10.66 (March 2014).
79
80
81       -maxval=maxval
82                   The maxval for the generated image.  Default is 255.
83
84                   This  option  was  new  in Netpbm 10.1 (June 2002).  Before
85              that, the maxval
86                   is always 255.
87
88
89
90
91

SEE ALSO

93       pamflip(1), pamarith(1), pnmgamma(1), pamseq(1), ppmrainbow(1), pamgra‐
94       dient(1), pgm(1)
95
96
97

AUTHOR

99       Copyright (C) 1989 by Jef Poskanzer.
100

DOCUMENT SOURCE

102       This  manual  page was generated by the Netpbm tool 'makeman' from HTML
103       source.  The master documentation is at
104
105              http://netpbm.sourceforge.net/doc/pgmramp.html
106
107netpbm documentation           15 February 2014         Pgmramp User Manual(0)
Impressum