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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 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} {} hot (@var{n}) |
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21 ## Create color colormap. This colormap is black through dark red, red, |
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22 ## orange, yellow to white. The argument @var{n} should be a scalar. If it |
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23 ## is omitted, the length of the current colormap or 64 is assumed. |
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24 ## @seealso{colormap} |
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25 ## @end deftypefn |
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26 |
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27 ## Author: Kai Habel <kai.habel@gmx.de> |
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28 |
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29 function map = hot (number) |
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30 |
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31 if (nargin == 0) |
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32 number = rows (colormap); |
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33 elseif (nargin == 1) |
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34 if (! isscalar (number)) |
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35 error ("hot: argument must be a scalar"); |
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36 endif |
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37 else |
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38 print_usage (); |
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39 endif |
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40 |
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41 if (number == 1) |
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42 map = [0, 0, 0]; |
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43 elseif (number > 1) |
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44 x = linspace (0, 1, number)'; |
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45 r = (x < 2/5) .* (5/2 * x) + (x >= 2/5); |
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46 g = (x >= 2/5 & x < 4/5) .* (5/2 * x - 1) + (x >= 4/5); |
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47 b = (x >= 4/5) .* (5*x - 4); |
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48 map = [r, g, b]; |
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49 else |
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50 map = []; |
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51 endif |
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52 |
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53 endfunction |
