1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
|
########################################################################
##
## Copyright (C) 1999-2024 The Octave Project Developers
##
## See the file COPYRIGHT.md in the top-level directory of this
## distribution or <https://octave.org/copyright/>.
##
## This file is part of Octave.
##
## Octave is free software: you can redistribute it and/or modify it
## under the terms of the GNU General Public License as published by
## the Free Software Foundation, either version 3 of the License, or
## (at your option) any later version.
##
## Octave is distributed in the hope that it will be useful, but
## WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
## GNU General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with Octave; see the file COPYING. If not, see
## <https://www.gnu.org/licenses/>.
##
########################################################################
## -*- texinfo -*-
## @deftypefn {} {@var{map} =} hsv ()
## @deftypefnx {} {@var{map} =} hsv (@var{n})
## Create color colormap. This colormap begins with red, changes through
## yellow, green, cyan, blue, and magenta, before returning to red.
##
## It is useful for displaying periodic functions. The map is obtained by
## linearly varying the hue through all possible values while keeping constant
## maximum saturation and value. The equivalent code is
## @code{hsv2rgb ([(0:N-1)'/N, ones(N,2)])}.
##
## The argument @var{n} must be a scalar.
## If unspecified, the length of the current colormap, or 64, is used.
## @seealso{colormap}
## @end deftypefn
function map = hsv (n)
if (nargin == 1)
if (! isscalar (n))
error ("hsv: N must be a scalar");
endif
n = double (n);
else
hf = get (0, "currentfigure");
if (! isempty (hf))
n = rows (get (hf, "colormap"));
else
n = 64;
endif
endif
if (n == 1)
map = [1, 0, 0];
elseif (n > 1)
hue = [0:n-1]' / n;
map = hsv2rgb ([hue, ones(n,1), ones(n,1)]);
else
map = zeros (0, 3);
endif
endfunction
## A better demo of this colormap would be to plot the hsv values.
%!demo
%! ## Show the 'hsv' colormap profile and as an image
%! cmap = hsv (256);
%! subplot (2, 1, 1);
%! rgbplot (cmap, "composite");
%! subplot (2, 1, 2);
%! rgbplot (cmap);
|
