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[project @ 2007-07-24 20:34:08 by dbateman]
author dbateman
date Tue, 24 Jul 2007 20:34:08 +0000
parents be31a048c449
children 93c65f2a5668
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1 ## Copyright (C) 1999,2000 Kai Habel
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2 ##
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3 ## This file is part of Octave.
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4 ##
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5 ## Octave is free software; you can redistribute it and/or modify it
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6 ## under the terms of the GNU General Public License as published by
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7 ## the Free Software Foundation; either version 2, or (at your option)
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8 ## any later version.
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9 ##
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10 ## Octave is distributed in the hope that it will be useful, but
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11 ## WITHOUT ANY WARRANTY; without even the implied warranty of
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12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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13 ## General Public License for more details.
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14 ##
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15 ## You should have received a copy of the GNU General Public License
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16 ## along with Octave; see the file COPYING. If not, write to the Free
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17 ## Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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18 ## 02110-1301, USA.
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19
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20 ## -*- texinfo -*-
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21 ## @deftypefn {Function File} {@var{map_out} =} brighten (@var{map}, @var{beta})
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22 ## @deftypefnx {Function File} {@var{map_out} =} brighten (@var{h}, @var{beta})
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23 ## @deftypefnx {Function File} {@var{map_out} =} brighten (@var{beta})
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24 ## Darkens or brightens the given colormap. If the @var{map} argument
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25 ## is omitted, the function is applied to the current colormap. The first
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26 ## argument can also be a valid graphics handle @var{h}, in which case
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27 ## @code{brighten} is applied to the colormap associated with this handle.
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28 ##
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29 ## Should the resulting colormap @var{map_out} not be assigned, it will be
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30 ## written to the current colormap.
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31 ##
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32 ## The argument @var{beta} should be a scalar between -1 and 1,
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33 ## where a negative value darkens and a positive value brightens
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34 ## the colormap.
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35 ## @seealso{colormap}
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36 ## @end deftypefn
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37
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38 function Rmap = brighten (m, beta)
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39 h = -1;
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40 if (nargin == 1)
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41 beta = m;
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42 m = colormap;
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43 h = gcf ();
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44 elseif (nargin == 2)
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45 if (ishandle (m))
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46 h = m;
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47 m = get (h, "colormap");
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48 elseif ((!is_matrix (m)) || (size (m, 2) != 3))
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49 error ("First argument must be a matrix of size nx3 or a handle.");
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50 endif
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51 else
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52 print_usage ();
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53 endif
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54
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55 if ( (!isscalar (beta)) || (beta <= -1) || (beta >= 1) )
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56 error ("brighten(...,beta) beta must be a scalar in the range (-1,1).");
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57 endif
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58
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59 if (beta > 0)
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60 gamma = 1 - beta;
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61 else
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62 gamma = 1 / (1 + beta);
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63 endif
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64
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65 if (nargout == 0)
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66 if (ishandle (h))
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67 set (h, "colormap", m .^ gamma);
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68 else
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69 colormap (m .^ gamma);
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70 endif
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71 else
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72 Rmap = m .^ gamma;
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73 endif
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74
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75 endfunction