function h = ft_plot_crosshair(pos, varargin)

% FT_PLOT_CROSSHAIR plots a crosshair at a specified position in two [x, y] or three

% [x, y, z] dimensions.

%

% Use as

% h = ft_plot_crosshair(pos, ...)

% where pos is the desired position of the crosshair. The handles of the lines are

% returned.

%

% Optional input arguments should be specified in key-value pairs and can include

% 'color' = [r g b] value or string, see PLOT

% 'parent' = handle which is set as the parent for the plotted elements (default = [])

% 'handle' = handle of the existing line objects to be updated

%

% You can specify the handles of existing line objects which will be then updated,

% rather than creating a new set of lines. If both parent and handle ar specified,

% the handle option prevail.

%

% Example

% ft_plot_crosshair([0.5 0.5], 'color', 'r')

%

% See also FT_PLOT_BOX, FT_PLOT_LINE, TEXT, LINE

% Copyright (C) 2003-2017, Robert Oostenveld

%

% This file is part of FieldTrip, see http://www.fieldtriptoolbox.org

% for the documentation and details.

%

% FieldTrip 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.

%

% FieldTrip 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 FieldTrip. If not, see <http://www.gnu.org/licenses/>.

%

% $Id$

% get the optional input arguments

color = ft_getopt(varargin, 'color');

parent = ft_getopt(varargin, 'parent');

h = ft_getopt(varargin, 'handle');

if ~isempty(h)

% the parent to the first handle is set as the current axes

set(gcf, 'currentaxes', get(h(1),'parent'));

elseif ~isempty(parent)

% the parent is set as the current axes

set(gcf, 'currentaxes', parent);

else

% the current axes stay as they are

end

% color management

if ~isempty(color)

if ischar(color) && exist([color '.m'], 'file')

color = eval(color);

elseif ischar(color) && ismember(color, htmlcolors)

color = htmlcolors(color);

end

varargin = ft_setopt(varargin, 'color', color);

end

% determine the size of the figure

border = [get(gca, 'xlim') get(gca, 'ylim') get(gca, 'zlim')];

switch numel(pos)

case 2

x = [ border(1) pos(1)

border(2) pos(1) ];

y = [ pos(2) border(3)

pos(2) border(4) ];

if isempty(h) && (~ishold)

hold on

h = line(x, y, varargin{:});

hold off

elseif isempty(h)

h = line(x, y, varargin{:});

else

set(h(1), 'xdata', x(:,1)');

set(h(1), 'ydata', y(:,1)');

set(h(2), 'xdata', x(:,2)');

set(h(2), 'ydata', y(:,2)');

end

if ~isempty(color)

set(h(1), 'color', color);

set(h(2), 'color', color);

else

% ensure they have the same color

set(h(2), 'color', get(h(1), 'color'));

end

case 3

x = [ border(1) pos(1) pos(1)

border(2) pos(1) pos(1)];

y = [ pos(2) border(3) pos(2)

pos(2) border(4) pos(2)];

z = [ pos(3) pos(3) border(5)

pos(3) pos(3) border(6)];

if isempty(h) && (~ishold)

hold on

h = line(x, y, z, varargin{:});

hold off

elseif isempty(h)

h = line(x, y, z, varargin{:});

else

set(h(1), 'xdata', x(:,1)');

set(h(1), 'ydata', y(:,1)');

set(h(1), 'zdata', z(:,1)');

set(h(2), 'xdata', x(:,2)');

set(h(2), 'ydata', y(:,2)');

set(h(2), 'zdata', z(:,2)');

set(h(3), 'xdata', x(:,3)');

set(h(3), 'ydata', y(:,3)');

set(h(3), 'zdata', z(:,3)');

end

if ~isempty(color)

set(h(1), 'color', color);

set(h(2), 'color', color);

set(h(3), 'color', color);

else

% ensure they have the same color

set(h(2), 'color', get(h(1), 'color'));

set(h(3), 'color', get(h(1), 'color'));

end

end % switch