Mercurial > octave
view scripts/image/private/ind2x.m @ 33669:96f077c60226 default tip @
maint: Merge stable to default.
author | Markus Mützel <markus.muetzel@gmx.de> |
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date | Wed, 19 Jun 2024 16:41:55 +0200 |
parents | 2e484f9f1f18 |
children |
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######################################################################## ## ## Copyright (C) 1994-2024 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 {} {[x, map] =} ind2x (@var{caller}, @var{x}, @var{map}) ## ## Private function for the ind2XXX functions which have a lot of code in ## common. ## @end deftypefn function [x, map] = ind2x (caller, x, map) ## Check if X is an indexed image. ## An indexed image is defined has having only 2 dimensions, and that's how ## Matlab behaves. But we want to support N-D images, so we will allow up to ## 4-D and check that the 3rd dimension is a singleton. if (all (ndims (x) != [2 4]) || size (x, 3) != 1 || iscomplex (x) || issparse (x) || ! (isfloat (x) && all (x(:) == fix (x(:))) || (isinteger (x) && intmin (x) == 0))) error ("%s: X must be an indexed image", caller); endif ## Check if map is a valid colormap. if (! iscolormap (map)) error ("%s: MAP must be a valid colormap", caller); endif ## Any color indices below the lower bound of the color map are modified ## to point to the first color in the map (see bug #41851). if (isfloat (x)) invalid_idx = x < 1; if (any (invalid_idx(:))) warning (["Octave:" caller ":invalid-idx-img"], [caller ": indexed image contains colors outside of colormap"]); x(invalid_idx) = 1; endif endif ## Switch to using 1-based indexing. ## It is possible that an integer storage class may not have enough room ## to make the switch, in which case we convert the data to single. maxidx = max (x(:)); is_int = isinteger (x); if (is_int) if (maxidx == intmax (x)) x = single (x); endif x += 1; endif ## When there are more colors in the image, than there are in the map, ## pad the colormap with the last color in the map for Matlab compatibility. num_colors = rows (map); if (num_colors - is_int < maxidx) warning (["Octave:" caller ":invalid-idx-img"], [caller ": indexed image contains colors outside of colormap"]); if (numel (x) > maxidx - num_colors + is_int) ## The image is large. So extend the map. pad = repmat (map(end,:), maxidx - num_colors + is_int, 1); map(end+(1:rows (pad)), :) = pad; else ## The map extension would be large. So clip the image. x(x > rows (map)) = rows (map); endif endif endfunction