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1 ## Copyright (C) 1999, 2000, 2007 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 3 of the License, or (at |
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8 ## your option) 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, see |
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17 ## <http://www.gnu.org/licenses/>. |
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18 |
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19 ## -*- texinfo -*- |
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20 ## @deftypefn {Function File} {@var{map_out} =} brighten (@var{map}, @var{beta}) |
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21 ## @deftypefnx {Function File} {@var{map_out} =} brighten (@var{h}, @var{beta}) |
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22 ## @deftypefnx {Function File} {@var{map_out} =} brighten (@var{beta}) |
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23 ## Darkens or brightens the given colormap. If the @var{map} argument |
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24 ## is omitted, the function is applied to the current colormap. The first |
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25 ## argument can also be a valid graphics handle @var{h}, in which case |
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26 ## @code{brighten} is applied to the colormap associated with this handle. |
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27 ## |
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28 ## Should the resulting colormap @var{map_out} not be assigned, it will be |
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29 ## written to the current colormap. |
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30 ## |
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31 ## The argument @var{beta} should be a scalar between -1 and 1, |
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32 ## where a negative value darkens and a positive value brightens |
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33 ## the colormap. |
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34 ## @seealso{colormap} |
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35 ## @end deftypefn |
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36 |
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37 function Rmap = brighten (m, beta) |
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38 h = -1; |
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39 if (nargin == 1) |
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40 beta = m; |
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41 m = colormap; |
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42 h = gcf (); |
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43 elseif (nargin == 2) |
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44 if (ishandle (m)) |
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45 h = m; |
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46 m = get (h, "colormap"); |
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47 elseif (! is_matrix (m) || size (m, 2) != 3) |
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48 error ("First argument must be a matrix of size nx3 or a handle."); |
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49 endif |
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50 else |
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51 print_usage (); |
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52 endif |
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53 |
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54 if (! isscalar (beta) || beta <= -1 || beta >= 1) |
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55 error ("brighten(...,beta) beta must be a scalar in the range (-1,1)."); |
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56 endif |
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57 |
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58 if (beta > 0) |
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59 gamma = 1 - beta; |
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60 else |
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61 gamma = 1 / (1 + beta); |
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62 endif |
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63 |
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64 if (nargout == 0) |
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65 if (ishandle (h)) |
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66 set (h, "colormap", m .^ gamma); |
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67 else |
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68 colormap (m .^ gamma); |
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69 endif |
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70 else |
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71 Rmap = m .^ gamma; |
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72 endif |
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73 |
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74 endfunction |
