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########################################################################
##
## Copyright (C) 2012-2024 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 {} {} rgbplot (@var{cmap})
## @deftypefnx {} {} rgbplot (@var{cmap}, @var{style})
## @deftypefnx {} {@var{h} =} rgbplot (@dots{})
## Plot the components of a colormap.
##
## Two different @var{style}s are available for displaying the @var{cmap}:
##
## @table @asis
## @item profile (default)
## Plot the RGB line profile of the colormap for each of the channels (red,
## green and blue) with the plot lines colored appropriately. Each line
## represents the intensity of an RGB component across the colormap.
##
## @item composite
## Draw the colormap across the X-axis so that the actual index colors are
## visible rather than the individual color components.
##
## @end table
##
## The optional return value @var{h} is a graphics handle to the created plot.
##
## Run @code{demo rgbplot} to see an example of @code{rgbplot} and each style
## option.
## @seealso{colormap}
## @end deftypefn
function h = rgbplot (cmap, style = "profile")
if (nargin < 1)
print_usage ();
endif
if (! iscolormap (cmap))
error ("rgbplot: CMAP must be a valid colormap");
elseif (! ischar (style))
error ("rgbplot: STYLE must be a string");
endif
switch (lower (style))
case "profile"
x = 1:rows (cmap);
htmp = plot (x,cmap(:,1),"r", x,cmap(:,2),"g", x,cmap(:,3),"b");
set (gca, "ytick", 0:0.1:1, "xlim", [0 rows(cmap)]);
case "composite"
htmp = image (1:rows (cmap));
set (gca, "ytick", []);
colormap (cmap);
otherwise
error ("rgbplot: unknown STYLE '%s'", style);
endswitch
xlabel ("color index");
if (nargout > 0)
h = htmp;
endif
endfunction
%!demo
%! clf;
%! subplot (1, 2, 1);
%! rgbplot (ocean, "profile");
%! subplot (1, 2, 2);
%! rgbplot (ocean, "composite");
## Test input validation
%!error <Invalid call> rgbplot ()
%!error <CMAP must be a valid colormap> rgbplot ({0 1 0})
%!error <STYLE must be a string> rgbplot ([0 1 0], 2)
%!error <unknown STYLE 'nostyle'> rgbplot ([0 1 0], "nostyle")
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