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########################################################################
##
## Copyright (C) 2010-2024 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 {} {} whitebg ()
## @deftypefnx {} {} whitebg (@var{color})
## @deftypefnx {} {} whitebg ("none")
## @deftypefnx {} {} whitebg (@var{hfig})
## @deftypefnx {} {} whitebg (@var{hfig}, @var{color})
## @deftypefnx {} {} whitebg (@var{hfig}, "none")
## Invert the colors in the current color scheme.
##
## The root properties are also inverted such that all subsequent plots will
## use the new color scheme.
##
## If the optional argument @var{color} is present then the background color
## is set to @var{color} rather than inverted. @var{color} may be a string
## representing one of the eight known colors or an RGB triplet. The special
## string argument @qcode{"none"} restores the plot to the factory default
## colors.
##
## If the first argument @var{hfig} is a figure handle or list of figure
## handles, then operate on these figures rather than the current figure
## returned by @code{gcf}. The root properties will not be changed unless 0
## is in the list of figures.
##
## Programming Note: @code{whitebg} operates by changing the color properties
## of the children of the specified figures. Only objects with a single color
## are affected. For example, a patch with a single @qcode{"FaceColor"} will
## be changed, but a patch with shading (@qcode{"interp"}) will not be
## modified. For inversion, the new color is simply the inversion in RGB
## space: @code{@var{cnew} = [1-@var{R} 1-@var{G} 1-@var{B}]}. When a color
## is specified, the axes and figure are set to the new color, and the color
## of child objects are then adjusted to have some contrast (visibility)
## against the new background.
## @seealso{reset, get, set}
## @end deftypefn
## FIXME: It's not clear whether Matlab also changes color properties
## of the figure object itself, or only the children. However, visually,
## it looks better to change the figure along with the axes background.
function whitebg (varargin)
if (nargin > 2)
print_usage ();
endif
h = 0;
color = NaN;
have_fig = false;
if (nargin > 0)
if (all (ishghandle (varargin{1})))
h = varargin{1};
have_fig = true;
if (nargin == 2)
color = varargin{2};
endif
elseif (nargin == 1)
color = varargin{1};
else
print_usage ();
endif
endif
if (! have_fig)
fig = gcf ();
do_root = true;
elseif (all (isfigure (h) | h == 0))
fig = h(h != 0);
do_root = any (h == 0);
else
error ("whitebg: HFIG must be a valid figure handle");
endif
if (isnan (color))
if (do_root)
## Set the default axes and figure properties on root
## so that subsequent plots have the new color scheme
fac = get (0, "factory");
fields = fieldnames (fac);
idx = ! cellfun ("isempty", regexp (fields,
'^factory(axes|figure).*color$'));
## Use default value in place of factory value if specified.
for field = fields(idx)'
defaultfield = strrep (field{1}, "factory", "default");
try
defaultvalue = 1 - get (0, defaultfield);
catch
defaultvalue = 1 - fac.(field{1});
end_try_catch
set (0, defaultfield, defaultvalue);
endfor
endif
## The sort is necessary so that child legend objects are acted on
## before the legend axes object.
hlist = sort (findobj (fig));
for h = hlist'
props = get (h);
fields = fieldnames (props);
## Find all fields with the word color in them and invert.
idx = find (! cellfun ("isempty", regexp (fields, 'color$')));
for field = fields(idx)'
c = props.(field{1});
if (! ischar (c) && columns (c) == 3)
set (h, field{1}, 1 - c);
endif
endfor
endfor
else # 2nd argument such as a color or "none"
if (! strcmp (color, "none"))
## Set the specified color on the figure and all axes objects
hlist = [fig; findobj(fig, "type", "axes")];
set (hlist, "color", color);
if (do_root)
defs = get (0, "default");
if (isfield (defs, "defaultaxescolor")
&& strcmp (defs.defaultaxescolor, "none"))
set (0, "defaultaxescolor", color);
endif
endif
## Adjust colors of remaining objects to have some contrast
bg = rgb2hsv (get (fig, "color"));
## List of children without the figure and axes objects already changed
hlist = setdiff (findobj (fig), hlist);
for h = hlist'
props = get (h);
fields = fieldnames (props);
## Find all fields with the word color in them and adjust HSV.
idx = find (! cellfun ("isempty", regexp (fields, 'color$')));
for field = fields(idx)'
c = props.(field{1});
if (! ischar (c) && columns (c) == 3)
set (h, field{1}, calc_contrast_color (bg, c));
endif
endfor
endfor
else
## Reset colors to factory defaults
if (do_root)
fac = get (0, "factory");
fields = fieldnames (fac);
idx = ! cellfun ("isempty", regexp (fields,
'^factory(axes|figure).*color$'));
for field = fields(idx)'
factoryfield = field{1};
factoryvalue = fac.(factoryfield);
if (strncmp (factoryfield, "factoryfigure", 13))
## Strip off "factoryfigure" part of fieldname before applying
set (fig, factoryfield(14:end), factoryvalue);
endif
## Remove applied default from root
defaultfield = strrep (factoryfield, "factory", "default");
set (0, defaultfield, "remove");
endfor
endif
hlist = sort (findobj (fig));
for h = hlist'
props = get (h);
fields = fieldnames (props);
## Find all fields with the word color in them and restore to factory.
idx = find (! cellfun ("isempty", regexp (fields, 'color$')));
for field = fields(idx)'
set (h, field{1}, "factory");
endfor
endfor
endif
endif
endfunction
## Calculate a new color which contrasts with the supplied bg color and is
## perceptually related to the original color.
##
## Input color bg must be in HSV space. Input color corig is in RGB space.
##
## FIXME: Calculation is segregated into its own function in case anyone wants
## to try and improve the selection of a "contrasting" color.
##
## This algorithm maintains at least 90 degrees separation between corig and bg
## in Hue rotation space. No modifications are done for saturation or value.
function cnew = calc_contrast_color (bg, corig)
hsv = rgb2hsv (corig);
contrast_hue = mod (bg(1) + 0.5, 1); # Generate a contrasting bg color
## If close to existing contrast color, leave alone
delta = abs (hsv(1) - contrast_hue);
if (delta < 0.25 || delta > 0.75)
cnew(1) = hsv(1);
else
cnew(1) = mod (hsv(1) + 0.5, 1);
endif
## No modifications to saturation or value.
cnew(2:3) = hsv(2:3);
cnew = hsv2rgb (cnew);
endfunction
%!test
%! dac = get (0, "defaultaxescolor");
%! dfc = get (0, "defaultfigurecolor");
%! hf = figure ("visible", "off");
%! unwind_protect
%! hl = line ("Color", "r");
%! assert (get (hf, "color"), dfc);
%! assert (get (gca, "color"), dac);
%! assert (get (hl, "color"), [1 0 0]);
%! whitebg (hf);
%! assert (get (hf, "color"), 1 - dfc);
%! assert (get (gca, "color"), 1 - dac);
%! assert (get (hl, "color"), [0 1 1]);
%! c = [0.2 0.2 0.2];
%! whitebg (hf, c);
%! assert (get (hf, "color"), c);
%! assert (get (gca, "color"), c);
%! unwind_protect_cleanup
%! close (hf);
%! end_unwind_protect
## Test input validation
%!error whitebg (1,2,3)
%!error whitebg ({1}, 2)
|
