Mercurial > octave-nkf
annotate scripts/image/hot.m @ 14279:f205d0074687
Update colormap files with faster code.
* autumn.m, bone.m, cool.m, copper.m, flag.m, gmap40.m, gray.m, hot.m, hsv.m,
jet.m, lines.m, ocean.m, pink.m, prism.m, rainbow.m, spring.m, summer.m,
white.m, winter.m: Use indexing in place of kron or repmat for faster code.
author | Rik <octave@nomad.inbox5.com> |
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date | Sat, 28 Jan 2012 22:33:57 -0800 |
parents | 11949c9795a0 |
children | b9c02ee24de1 |
rev | line source |
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maint: update copyright notices for 2012
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1 ## Copyright (C) 1999-2012 Kai Habel |
6788 | 2 ## |
3 ## This file is part of Octave. | |
4 ## | |
5 ## Octave is free software; you can redistribute it and/or modify it | |
6 ## under the terms of the GNU General Public License as published by | |
7016 | 7 ## the Free Software Foundation; either version 3 of the License, or (at |
8 ## your option) any later version. | |
6788 | 9 ## |
10 ## Octave is distributed in the hope that it will be useful, but | |
11 ## WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 ## General Public License for more details. | |
14 ## | |
15 ## You should have received a copy of the GNU General Public License | |
7016 | 16 ## along with Octave; see the file COPYING. If not, see |
17 ## <http://www.gnu.org/licenses/>. | |
6788 | 18 |
19 ## -*- texinfo -*- | |
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20 ## @deftypefn {Function File} {@var{map} =} hot () |
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21 ## @deftypefnx {Function File} {@var{map} =} hot (@var{n}) |
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22 ## Create color colormap. This colormap ranges from black through dark red, |
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23 ## red, orange, yellow, to white. |
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24 ## The argument @var{n} must be a scalar. |
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25 ## If unspecified, the length of the current colormap, or 64, is used. |
6788 | 26 ## @seealso{colormap} |
27 ## @end deftypefn | |
28 | |
29 ## Author: Kai Habel <kai.habel@gmx.de> | |
30 | |
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31 function map = hot (n) |
6788 | 32 |
33 if (nargin == 0) | |
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34 n = rows (colormap); |
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35 elseif (nargin == 1) |
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36 if (! isscalar (n)) |
6788 | 37 error ("hot: argument must be a scalar"); |
38 endif | |
39 else | |
40 print_usage (); | |
41 endif | |
42 | |
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43 if (n == 1) |
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44 map = [0, 0, 0]; |
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45 elseif (n > 1) |
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46 x = linspace (0, 1, n)'; |
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47 r = (x < 2/5) .* (5/2 * x) ... |
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48 + (x >= 2/5); |
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49 g = (x >= 2/5 & x < 4/5) .* (5/2 * x - 1) ... |
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50 + (x >= 4/5); |
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51 b = (x >= 4/5) .* (5 * x - 4); |
6788 | 52 map = [r, g, b]; |
53 else | |
54 map = []; | |
55 endif | |
56 | |
57 endfunction | |
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58 |
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59 |
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60 %!demo |
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61 %! ## Show the 'hot' colormap as an image |
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62 %! image (1:64, linspace (0, 1, 64), repmat ((1:64)', 1, 64)); |
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63 %! axis ([1, 64, 0, 1], "ticy", "xy"); |
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64 %! colormap (hot (64)); |
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65 |