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########################################################################
##
## Copyright (C) 2014-2024 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{x}, @var{map}] =} frame2im (@var{frame})
## Convert movie frame to indexed image.
##
## A movie frame is simply a struct with the fields @qcode{"cdata"} and
## @qcode{"colormap"}.
##
## Support for N-dimensional images or movies is given when @var{frame} is a
## struct array. In such cases, @var{x} will be a @nospell{MxNx1xK or MxNx3xK}
## for indexed and RGB movies respectively, with each frame concatenated
## along the 4th dimension.
##
## @seealso{im2frame, getframe}
## @end deftypefn
function [x, map] = frame2im (frame)
if (nargin < 1)
print_usage ();
elseif (! all (isfield (frame, {"cdata", "colormap"})))
error ("frame2im: F must be a struct with the fields colormap and cdata");
endif
n = numel (frame);
if (n == 0)
error ("frame2im: FRAME is empty");
else
x = [frame.cdata];
map = frame(1).colormap;
endif
## support for N-dimensional images if we receive a struct array
if (n > 1)
x = reshape (x, rows (x), columns (x) / n, n, size (frame(1).cdata, 3));
x = permute (x, [1 2 4 3]);
endif
endfunction
%!function f = make_rgb_f ()
%! f = randi ([0 255], 10, 20, 3);
%!endfunction
%!function f = make_ind_f ()
%! f = randi ([1 100], 10, 20, 2);
%!endfunction
%!test
%! x = make_ind_f ();
%! cmap = jet (100);
%! frame = struct ("cdata", x, "colormap", cmap);
%! [rx, rcmap] = frame2im (frame);
%! assert (rx, x);
%! assert (rcmap, cmap);
%!test
%! rgb = make_rgb_f ();
%! frame = struct ("cdata", rgb, "colormap", []);
%! [rrgb, rcmap] = frame2im (frame);
%! assert (rrgb, rgb);
%! assert (rcmap, []);
%!test
%! f1 = make_rgb_f ();
%! f2 = make_rgb_f ();
%! f3 = make_rgb_f ();
%! f4 = make_rgb_f ();
%! rgb = {f1, f2, f3, f4};
%! movie = struct ("cdata", rgb, "colormap", []);
%! [rx, rcmap] = frame2im (movie);
%! assert (rx, cat (4, f1, f2, f3, f4));
%! assert (rcmap, []);
%!test
%! f1 = make_ind_f ();
%! f2 = make_ind_f ();
%! f3 = make_ind_f ();
%! f4 = make_ind_f ();
%! ind = {f1, f2, f3, f4};
%! cmap = jet (100);
%! movie = struct ("cdata", ind, "colormap", cmap);
%! [rx, rcmap] = frame2im (movie);
%! assert (rx, cat (4, f1, f2, f3, f4));
%! assert (rcmap, cmap);
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