Mercurial > octave
view scripts/image/cmpermute.m @ 31215:5573b1d511c9
maint: Merge stable to default.
author | Markus Mützel <markus.muetzel@gmx.de> |
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date | Tue, 30 Aug 2022 11:16:55 +0200 |
parents | 796f54d4ddbf |
children | 597f3ee61a48 |
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######################################################################## ## ## Copyright (C) 2004-2022 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{Y}, @var{newmap}] =} cmpermute (@var{X}, @var{map}) ## @deftypefnx {} {[@var{Y}, @var{newmap}] =} cmpermute (@var{X}, @var{map}, @var{index}) ## Reorder colors in a colormap. ## ## When called with only two arguments, @code{cmpermute} randomly rearranges ## the colormap @var{map} and returns a new colormap @var{newmap}. It also ## returns the indexed image @var{Y} which is the equivalent of the original ## input image @var{X} when displayed using @var{newmap}. ## ## When called with an optional third argument the order of colors in the new ## colormap is defined by @var{index}. ## ## @strong{Caution:} @var{index} should not have repeated elements or the ## function will fail. ## ## @end deftypefn function [Y, newmap] = cmpermute (X, map, index) if (nargin < 2) print_usage (); endif cls = class (X); if (! any (strcmp (cls, {"uint8", "uint16", "single", "double"}))) error ("cmpermute: invalid data type '%s'", cls); endif if (! isreal (X) || issparse (X) || (isfloat (X) && (any (X(:) < 1 || any (X(:) != fix (X(:))))))) error ("cmpermute: X must be an indexed image"); endif if (! iscolormap (map) || min (map(:)) < 0 || max (map(:)) > 1) error ("cmpermute: MAP must be a valid colormap"); endif if (nargin < 3) index = randperm (rows (map)); elseif (! isvector (index) || length (index) != rows (map)) error ("cmpermute: invalid parameter INDEX"); endif ## new colormap newmap = map(index,:); ## build reverse index rindex = zeros (size (index)); rindex(index) = 1:length (index); ## preserve class of input image in output if (strcmp (cls, "double")) Y = rindex(X); elseif (strcmp (cls, "single")) rindex = single (rindex); Y = rindex(X); else ## adapt indices rindex = feval (cls, rindex - 1); ## 0-based indices Y = rindex(single (X) + 1); endif endfunction %!demo %! [Y, newmap] = cmpermute ([1:4], hot (4), 4:-1:1) %! ## colormap will be arranged in reverse order (so will image) %!shared X, map %! X = uint8 (magic (16)); %! [X, map] = cmunique (X); %!test # random permutation, 0-based index %! [Y, newmap] = cmpermute (X, map); %! ## test we didn't lose colors %! assert (sort (map), sortrows (newmap)); %! ## test if images are equal %! assert (map(double (X)+1), newmap(double (Y)+1)); %!test # reverse map, 0-based index %! [Y, newmap] = cmpermute (X, map, rows (map):-1:1); %! ## we expect a reversed colormap %! assert (flipud (newmap), map); %! ## we expect reversed indices in image %! assert (X, max (Y(:)) - Y); %!shared X,map %! X = uint16 (magic (20)); %! [X, map] = cmunique (X); %!test # random permutation, 1-based index %! [Y, newmap] = cmpermute (X, map); %! ## test we didn't lose colors %! assert (sort (map), sortrows (newmap)); %! ## test if images are equal %! assert (map(X), newmap(Y)); %!test # reverse map, 1-based index %! [Y, newmap] = cmpermute (X, map, rows (map):-1:1); %! ## we expect a reversed colormap %! assert (newmap (rows (newmap):-1:1,:), map); %! ## we expect reversed indices in image %! assert (X, max (Y(:)) + 1 - Y); ## Test input validation %!error <Invalid call> cmpermute () %!error <Invalid call> cmpermute (1) %!error <invalid data type 'uint32'> cmpermute (uint32 (magic (16)), jet (256)) %!error <X must be an indexed image> cmpermute (1+i, jet (256)) %!error <X must be an indexed image> cmpermute (sparse (1), jet (256)) %!error <X must be an indexed image> cmpermute (0, jet (256)) %!error <X must be an indexed image> cmpermute (1.5, jet (256)) %!error <MAP must be a valid colormap> cmpermute (1, "a") %!error <MAP must be a valid colormap> cmpermute (1, i) %!error <MAP must be a valid colormap> cmpermute (1, ones (3,3,3)) %!error <MAP must be a valid colormap> cmpermute (1, ones (3,2)) %!error <MAP must be a valid colormap> cmpermute (1, [-1 1 1]) %!error <MAP must be a valid colormap> cmpermute (1, [2 1 1]) %!error <invalid parameter INDEX> cmpermute (1, [0 1 0;1 0 1], ones (3)) %!error <invalid parameter INDEX> cmpermute (1, [0 1 0;1 0 1], 1:3)