Mercurial > octave
view scripts/image/bone.m @ 33528:6813c5c7e1b9 default tip @
Update to gnulib revision 6213c5bd72d15ca5e1ea9c34122899e02fed448c.
* bootstrap.conf: Update GNULIB_REVISION that contains a fix for a build issue
when targeting Cygwin.
author | Markus Mützel <markus.muetzel@gmx.de> |
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date | Fri, 03 May 2024 16:04:05 +0200 |
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} =} bone () ## @deftypefnx {} {@var{map} =} bone (@var{n}) ## Create color colormap. This colormap varies from black to white with ## gray-blue shades. ## ## 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 function map = bone (n) if (nargin == 1) if (! (isscalar (n) && isreal (n) && n == fix (n))) error ("bone: 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 = [1/8 1/8 1/8]; elseif (n == 2) map = [1/16 1/8 1/8 1 1 1 ]; elseif (n > 2) x = [0:n-1]' / (n-1); idx = floor (3/4*n); nel = n - idx + 1; # number of elements rem = mod (n, 8); switch (rem) case {2, 4} base = 1 / (16 + 2*(n-rem)); case {5, 7} base = 1 / (24 + 2*(n-rem)); otherwise base = 0; endswitch r(1:idx,1) = 7/8 * x(1:idx); r(idx:n,1) = linspace (7/8 * x(idx) + base, 1, nel); idx = floor (3/8 * n); nel = idx + 1; g(1:idx,1) = 7/8 * x(1:idx); g(idx:2*idx,1) = linspace (7/8 * x(idx), 7/8 * x(2*idx) + 1/8, nel); g(2*idx+1:n,1) = 7/8 * x(2*idx+1:n) + 1/8; base = 1 / (8*idx); nel = idx; b(1:idx,1) = linspace (base, 7/8 * x(idx) + 1/8, nel); b(idx:n,1) = 7/8 * x(idx:n) + 1/8; map = [r, g, b]; else map = zeros (0, 3); endif endfunction %!demo %! ## Show the 'bone' colormap profile and as an image %! cmap = bone (256); %! subplot (2, 1, 1); %! rgbplot (cmap, "composite"); %! subplot (2, 1, 2); %! rgbplot (cmap); %!assert (size (bone ()), [256, 3]) %!assert (size (bone (16)), [16, 3]) %!assert (bone (1), [1/8, 1/8, 1/8]) %!assert (bone (true), double ([1/8, 1/8, 1/8])) %!assert (bone (char (1)), double ([1/8, 1/8, 1/8])) %!assert (bone (int32 (1)), double ([1/8, 1/8, 1/8])) %!assert (bone (2), [1/16, 1/8, 1/8; 1 ,1, 1]) %!assert (bone (0), zeros (0, 3)) %!assert (bone (-1), zeros (0, 3)) %!test %! a = [ 0, 0, 1/8; %! 7/32, 11/32, 11/32; %! 23/48, 9/16, 9/16; %! 71/96, 25/32, 25/32; %! 1, 1, 1]; %! assert (bone (5), a, eps) ## Input validation %!error <N must be a scalar integer> bone ("foo") %!error <N must be a scalar integer> bone ([1, 2, 3]) %!error <N must be a scalar integer> bone ({1, 2, 3})