Mercurial > octave-nkf
view scripts/image/brighten.m @ 6792:bbe79d3ed56a
[project @ 2007-07-24 20:34:08 by dbateman]
author | dbateman |
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date | Tue, 24 Jul 2007 20:34:08 +0000 |
parents | be31a048c449 |
children | 93c65f2a5668 |
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## Copyright (C) 1999,2000 Kai Habel ## ## 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 2, 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, write to the Free ## Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA ## 02110-1301, USA. ## -*- texinfo -*- ## @deftypefn {Function File} {@var{map_out} =} brighten (@var{map}, @var{beta}) ## @deftypefnx {Function File} {@var{map_out} =} brighten (@var{h}, @var{beta}) ## @deftypefnx {Function File} {@var{map_out} =} brighten (@var{beta}) ## Darkens or brightens the given 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. ## ## Should the resulting colormap @var{map_out} not be assigned, it will be ## written to the current colormap. ## ## The argument @var{beta} should be a scalar between -1 and 1, ## where a negative value darkens and a positive value brightens ## the colormap. ## @seealso{colormap} ## @end deftypefn function Rmap = brighten (m, beta) h = -1; if (nargin == 1) beta = m; m = colormap; h = gcf (); elseif (nargin == 2) if (ishandle (m)) h = m; m = get (h, "colormap"); elseif ((!is_matrix (m)) || (size (m, 2) != 3)) error ("First argument must be a matrix of size nx3 or a handle."); endif else print_usage (); endif if ( (!isscalar (beta)) || (beta <= -1) || (beta >= 1) ) error ("brighten(...,beta) 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 (ishandle (h)) set (h, "colormap", m .^ gamma); else colormap (m .^ gamma); endif else Rmap = m .^ gamma; endif endfunction