Mercurial > octave
view scripts/image/ind2rgb.m @ 31602:16fb0e3e6aab
maint: Merge stable to default.
author | John W. Eaton <jwe@octave.org> |
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date | Thu, 01 Dec 2022 15:04:44 -0500 |
parents | 796f54d4ddbf |
children | 597f3ee61a48 |
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######################################################################## ## ## Copyright (C) 1994-2022 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{rgb} =} ind2rgb (@var{x}, @var{map}) ## @deftypefnx {} {[@var{R}, @var{G}, @var{B}] =} ind2rgb (@var{x}, @var{map}) ## Convert an indexed image to red, green, and blue color components. ## ## The image @var{x} must be an indexed image which will be converted using the ## colormap @var{map}. If @var{map} does not contain enough colors for the ## image, pixels in @var{x} outside the range are mapped to the last color in ## the map. ## ## The output may be a single RGB image (@nospell{MxNx3} matrix where M and N ## are the original image @var{x} dimensions, one for each of the red, green ## and blue channels). Alternatively, the individual red, green, and blue ## color matrices of size @nospell{MxN} may be returned. ## ## Multi-dimensional indexed images (of size @nospell{MxNx1xK}) are also ## supported. ## ## @seealso{rgb2ind, ind2gray, hsv2rgb} ## @end deftypefn function [R, G, B] = ind2rgb (x, map) if (nargin != 2) print_usage (); endif [x, map] = ind2x ("ind2rgb", x, map); ## Compute result sz = size (x); R = reshape (map(x(:), 1), sz); G = reshape (map(x(:), 2), sz); B = reshape (map(x(:), 3), sz); ## Use ND array if only one output is requested. if (nargout <= 1) if (ndims (x) == 2) R = reshape ([R(:); G(:); B(:)], [sz, 3]); elseif (ndims (x) == 4) R = permute (reshape ([R(:); G(:); B(:)], [sz(1) sz(2) sz(4) 3]), ... [1 2 4 3]); else ## we should never reach here since ind2x() should filter them out error ("ind2rgb: an indexed image must have 2 or 4 dimensions"); endif endif endfunction %!shared img, map, ergb, rgb, r, g, b %! img = [2 4 5; 3 2 5; 1 2 4]; %! map = [0.0 0.0 0.0 %! 0.2 0.4 0.6 %! 0.4 0.4 0.5 %! 0.3 0.7 1.0 %! 0.1 0.5 0.8]; %! ergb(:,:,1) = [0.2 0.3 0.1; 0.4 0.2 0.1; 0.0 0.2 0.3]; %! ergb(:,:,2) = [0.4 0.7 0.5; 0.4 0.4 0.5; 0.0 0.4 0.7]; %! ergb(:,:,3) = [0.6 1.0 0.8; 0.5 0.6 0.8; 0.0 0.6 1.0]; %! ## test basic usage with 1 and 3 outputs %! [rgb] = ind2rgb (img, map); %! [r, g, b] = ind2rgb (img, map); %! %!assert (ergb, rgb) %!assert (ergb, reshape ([r(:) g(:) b(:)], [size(img) 3])) %!test %! ## test correction for integers %! img = uint8 (img - 1); %! [rgb] = ind2rgb (img, map); %! assert (ergb, rgb); %!test %! ## Check that values below lower bound are mapped to first color value %! warning ("off", "Octave:ind2rgb:invalid-idx-img", "local"); %! rgb = ind2rgb ([-1 0 2], gray (64)); %! assert (rgb(:,1:2,:), zeros (1,2,3)); %! assert (rgb(:,3,:), 1/63 * ones (1,1,3)); ## Test input validation %!error <Invalid call> ind2rgb () %!error <Invalid call> ind2rgb (1) %!error <X must be an indexed image> ind2rgb (ones (3,3,3), jet (64)) %!error <X must be an indexed image> ind2rgb (1+i, jet (64)) %!error <X must be an indexed image> ind2rgb (sparse (1), jet (64)) %!error <X must be an indexed image> ind2rgb (1.1, jet (64)) %!error <X must be an indexed image> ind2rgb ({1}, jet (64)) %!error <MAP must be a valid colormap> ind2rgb (1, {1}) %!error <MAP must be a valid colormap> ind2rgb (1, 1+i) %!error <MAP must be a valid colormap> ind2rgb (1, ones (2,2,2)) %!error <MAP must be a valid colormap> ind2rgb (1, ones (2,4)) %!error <MAP must be a valid colormap> ind2rgb (1, [-1]) %!error <MAP must be a valid colormap> ind2rgb (1, [2]) %!warning <contains colors outside of colormap> ind2rgb ([-1 1], jet (64)); %!warning <contains colors outside of colormap> ind2rgb ([0 1 2], gray (5)); %!warning <contains colors outside of colormap> ind2rgb ([1 2 6], gray (5)); %!warning <contains colors outside of colormap> ind2rgb (uint8 ([1 2 5]), gray (5)); ## We support any unsigned integer type which Matlab does not. See ## bug #47115. %!test %! cmap = repmat (linspace (0, 1, 9)(:), [1 3]); %! ind = [0 3 6; 1 4 7; 2 5 8]; %! rgb = repmat (reshape (linspace (0, 1, 9), [3 3]), [1 1 3]); %! assert (ind2rgb (uint8 (ind), cmap), rgb); %! assert (ind2rgb (uint16 (ind), cmap), rgb); %! assert (ind2rgb (uint32 (ind), cmap), rgb); %! assert (ind2rgb (uint64 (ind), cmap), rgb); %! fail ("ind2rgb (int8 (ind), cmap)", "X must be an indexed image") %! fail ("ind2rgb (int16 (ind), cmap)", "X must be an indexed image") %! fail ("ind2rgb (int32 (ind), cmap)", "X must be an indexed image") %! fail ("ind2rgb (int64 (ind), cmap)", "X must be an indexed image") %! %! cmap(65541,:) = cmap(9,:); # index outside the uint16 range %! cmap(9,:) = 0; %! ind(3,3) = 65540; %! assert (ind2rgb (uint32 (ind), cmap), rgb); %! assert (ind2rgb (uint64 (ind), cmap), rgb); %!test <*59242> %! warning ("off", "Octave:ind2rgb:invalid-idx-img", "local"); %! assert (ind2rgb (uint64 (intmax ("uint64")), jet (64)), ... %! reshape ([0.5,0,0], [1,1,3]));