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
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
|
########################################################################
##
## 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_out} =} brighten (@var{beta})
## @deftypefnx {} {@var{map_out} =} brighten (@var{map}, @var{beta})
## @deftypefnx {} {@var{map_out} =} brighten (@var{h}, @var{beta})
## @deftypefnx {} {} brighten (@dots{})
## Brighten or darken a colormap.
##
## The argument @var{beta} must be a scalar between -1 and 1, where a negative
## value darkens and a positive value brightens the colormap.
##
## If the @var{map} argument is omitted, the function is applied to the current
## colormap.
##
## The first argument can also be a valid graphics handle @var{h}, in which
## case @code{brighten} is applied to the colormap associated with this handle.
##
## If no output is specified then the result is written to the current
## colormap.
## @seealso{colormap, contrast}
## @end deftypefn
function rmap = brighten (arg1, beta)
if (nargin < 1)
print_usage ();
endif
h = -1;
if (nargin == 1)
beta = arg1;
m = colormap ();
h = gcf ();
else
if (ishghandle (arg1))
h = arg1;
m = get (h, "colormap");
elseif (iscolormap (arg1))
m = arg1;
else
error ("brighten: first argument must be a colormap or a graphics handle");
endif
endif
if (! isscalar (beta) || beta <= -1 || beta >= 1)
error ("brighten: BETA must be a scalar in the range (-1,1)");
endif
if (beta > 0)
gamma = 1 - beta;
else
gamma = 1 / (1 + beta);
endif
if (nargout == 0)
if (ishghandle (h))
set (h, "colormap", m .^ gamma);
else
colormap (m .^ gamma);
endif
else
rmap = m .^ gamma;
endif
endfunction
%!demo
%! ## First figure uses default grayscale colormap
%! clf;
%! colormap (gray (64));
%! image (1:64, linspace (0, 1, 64), repmat ((1:64)', 1, 64));
%! axis ([1, 64, 0, 1], "xy");
%! set (gca, "xtick", []);
%! title ("default grayscale colormap");
%! pos = get (gcf, "position");
%! pos(1) += pos(3) + 25;
%! ## Second figure uses brightened grayscale colormap
%! figure ("position", pos);
%! colormap (gray (64));
%! image (1:64, linspace (0, 1, 64), repmat ((1:64)', 1, 64));
%! axis ([1, 64, 0, 1], "xy");
%! set (gca, "xtick", []);
%! brighten (0.5);
%! title ("grayscale colormap brightened by 0.5");
|
