Mercurial > octave
view scripts/image/rainbow.m @ 33529:4aec1230dd8f bytecode-interpreter tip
maint: Merge default to bytecode-interpreter
author | Arun Giridhar <arungiridhar@gmail.com> |
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date | Sat, 04 May 2024 08:31:05 -0400 |
parents | d8e5e55c3cf5 |
children |
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######################################################################## ## ## Copyright (C) 1999-2024 The Octave Project Developers ## ## See the file COPYRIGHT.md in the top-level directory of this ## distribution or <https://octave.org/copyright/>. ## ## 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 3 of the License, 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, see ## <https://www.gnu.org/licenses/>. ## ######################################################################## ## -*- texinfo -*- ## @deftypefn {} {@var{map} =} rainbow () ## @deftypefnx {} {@var{map} =} rainbow (@var{n}) ## Create color colormap. This colormap ranges from red through orange, ## yellow, green, blue, to violet. ## ## The argument @var{n} must be a scalar. ## If @var{n} is not specified the length of the current colormap is used. If ## there is no current colormap the default value of 256 is used. ## @seealso{colormap} ## @end deftypefn ## this colormap is not part of matlab, it is like the prism ## colormap map but with a continuous map function map = rainbow (n) if (nargin == 1) if (! (isscalar (n) && isreal (n) && n == fix (n))) error ("rainbow: N must be a scalar integer"); endif n = double (n); else hf = get (0, "currentfigure"); if (! isempty (hf)) n = rows (get (hf, "colormap")); else n = 256; endif endif if (n == 1) map = [1, 0, 0]; elseif (n > 1) x = [0:(n-1)]' / (n - 1); r = ( (x < 2/5) + (x >= 2/5 & x < 3/5) .* (-5 * x + 3) + (x >= 4/5) .* (10/3 * x - 8/3)); g = ( (x < 2/5) .* (5/2 * x) + (x >= 2/5 & x < 3/5) + (x >= 3/5 & x < 4/5) .* (-5 * x + 4)); b = ( (x >= 3/5 & x < 4/5) .* (5 * x - 3) + (x >= 4/5)); map = [r, g, b]; else map = zeros (0, 3); endif endfunction %!demo %! ## Show the 'rainbow' colormap profile and as an image %! cmap = rainbow (256); %! subplot (2, 1, 1); %! rgbplot (cmap, "composite"); %! subplot (2, 1, 2); %! rgbplot (cmap); %!assert (size (rainbow ()), [256, 3]) %!assert (size (rainbow (16)), [16, 3]) %!assert (rainbow (1), [1, 0, 0]) %!assert (rainbow (true), double ([1, 0, 0])) %!assert (rainbow (char (1)), double ([1, 0, 0])) %!assert (rainbow (int32 (1)), double ([1, 0, 0])) %!assert (rainbow (0), zeros (0, 3)) %!assert (rainbow (-1), zeros (0, 3)) %!assert (rainbow (6)(:), [1, 1, 1, 0, 0, 2/3, 0, 0.5, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1]', 3*eps) ## Input validation %!error <N must be a scalar integer> rainbow ("foo") %!error <N must be a scalar integer> rainbow ([1, 2, 3]) %!error <N must be a scalar integer> rainbow ({1, 2, 3})