function [cfg] = ft_topoplotER(cfg, varargin)

% FT_TOPOPLOTER plots the topographic distribution over the head of a 2-dimensional
% data representations such as the event-related potentials or fields, or a power
% or connectivity spectrum.
%
% Use as
%   ft_topoplotER(cfg, timelock)
% or
%   ft_topoplotER(cfg, freq)
%
% The data can be an ERP/ERF produced by FT_TIMELOCKANALYSIS, a power spectrum
% (without time dimension) produced by FT_FREQANALYSIS or a connectivity spectrum
% produced by FT_CONNECTIVITYANALYSIS. Also, the output to FT_FREQSTATISTICS and
% FT_TIMELOCKSTATISTICS can be visualised.
%
% The configuration can have the following parameters
%   cfg.parameter          = field that contains the data to be plotted as color, for example 'avg', 'powspctrm' or 'cohspctrm' (default is automatic)
%   cfg.maskparameter      = field in the data to be used for masking of data. It should have alues between 0 and 1, where 0 corresponds to transparent.
%   cfg.xlim               = limit for 1st dimension in data (e.g., time), can be 'maxmin' or [xmin xmax] (default = 'maxmin')
%   cfg.zlim               = limits for color dimension, 'maxmin', 'maxabs', 'zeromax', 'minzero', or [zmin zmax] (default = 'maxmin')
%   cfg.channel            = Nx1 cell-array with selection of channels (default = 'all'), see FT_CHANNELSELECTION for details
%   cfg.refchannel         = name of reference channel for visualising connectivity, can be 'gui'
%   cfg.baseline           = 'yes','no' or [time1 time2] (default = 'no'), see FT_TIMELOCKBASELINE or FT_FREQBASELINE
%   cfg.baselinetype       = 'absolute' or 'relative' (default = 'absolute')
%   cfg.trials             = 'all' or a selection given as a 1xN vector (default = 'all')
%   cfg.colormap           = string, or Nx3 matrix, see FT_COLORMAP
%   cfg.marker             = 'on', 'labels', 'numbers', 'off'
%   cfg.markersymbol       = channel marker symbol (default = 'o')
%   cfg.markercolor        = channel marker color (default = [0 0 0] (black))
%   cfg.markersize         = channel marker size (default = 2)
%   cfg.markerfontsize     = font size of channel labels (default = 8 pt)
%   cfg.highlight          = 'off', 'on', 'labels', 'numbers'
%   cfg.highlightchannel   =  Nx1 cell-array with selection of channels, or vector containing channel indices see FT_CHANNELSELECTION
%   cfg.highlightsymbol    = highlight marker symbol (default = 'o')
%   cfg.highlightcolor     = highlight marker color (default = [0 0 0] (black))
%   cfg.highlightsize      = highlight marker size (default = 6)
%   cfg.highlightfontsize  = highlight marker size (default = 8)
%   cfg.hotkeys            = enables hotkeys (pageup/pagedown/m) for dynamic zoom and translation (ctrl+) of the color limits
%   cfg.colorbar           = whether to show a colorbar alongside the figure (default = 'no')
%                            'no'                 do not show a colorbar
%                            'yes'                at the default MATLAB location
%                            'North'              inside plot box near top
%                            'South'              inside bottom
%                            'East'               inside right
%                            'West'               inside left
%                            'NorthOutside'       outside plot box near top
%                            'SouthOutside'       outside bottom
%                            'EastOutside'        outside right
%                            'WestOutside'        outside left
%   cfg.colorbartext       =  string indicating the text next to colorbar
%   cfg.interplimits       = limits for interpolation (default = 'head')
%                            'electrodes'         to furthest electrode
%                            'head'               to edge of head
%   cfg.interpolation      = 'linear','cubic','nearest','v4' (default = 'v4') see GRIDDATA
%   cfg.style              = plot style (default = 'both')
%                            'straight'           colormap only
%                            'contour'            contour lines only
%                            'both'               both colormap and contour lines
%                            'fill'               constant color between lines
%                            'blank'               only the head shape
%   cfg.gridscale          = scaling grid size that determines resolution of figure (default = 67)
%   cfg.shading            = 'flat' or 'interp' (default = 'flat')
%   cfg.comment            = 'no', 'auto' or 'xlim' (default = 'auto')
%                            'auto': date, xparam and zparam limits are printed
%                            'xlim': only xparam limits are printed
%   cfg.commentpos         = string or two numbers, position of the comment (default = 'leftbottom')
%                            'lefttop' 'leftbottom' 'middletop' 'middlebottom' 'righttop' 'rightbottom'
%                            'title' to place comment as title
%                            'layout' to place comment as specified for COMNT in layout
%                            [x y] coordinates
%   cfg.interactive        = Interactive plot 'yes' or 'no' (default = 'yes')
%                            In a interactive plot you can select areas and produce a new
%                            interactive plot when a selected area is clicked. Multiple areas
%                            can be selected by holding down the SHIFT key.
%   cfg.directionality     = '', 'inflow' or 'outflow' specifies for
%                            connectivity measures whether the inflow into a
%                            node, or the outflow from a node is plotted. The
%                            (default) behavior of this option depends on the dimord
%                            of the input data (see below).
%   cfg.layout             = specify the channel layout for plotting using one of the supported ways (see below).
%   cfg.interpolatenan     = 'yes' or 'no', whether to interpolate over channels containing NaNs (default = 'yes')
%   cfg.figure             = 'yes' or 'no', whether to open a new figure. You can also specify a figure handle from FIGURE, GCF or SUBPLOT. (default = 'yes')
%
% For the plotting of directional connectivity data the cfg.directionality option
% determines what is plotted. The default value and the supported functionality
% depend on the dimord of the input data. If the input data is of dimord
% 'chan_chan_XXX', the value of directionality determines whether, given the
% reference channel(s), the columns (inflow), or rows (outflow) are selected for
% plotting. In this situation the default is 'inflow'. Note that for undirected
% measures, inflow and outflow should give the same output. If the input data is of
% dimord 'chancmb_XXX', the value of directionality determines whether the rows in
% data.labelcmb are selected. With 'inflow' the rows are selected if the
% refchannel(s) occur in the right column, with 'outflow' the rows are selected if
% the refchannel(s) occur in the left column of the labelcmb-field. Default in this
% case is '', which means that all rows are selected in which the refchannel(s)
% occur. This is to robustly support linearly indexed undirected connectivity
% metrics. In the situation where undirected connectivity measures are linearly
% indexed, specifying 'inflow' or 'outflow' can result in unexpected behavior.
%
% The layout defines how the channels are arranged. You can specify the
% layout in a variety of ways:
%  - you can provide a pre-computed layout structure, see FT_PREPARE_LAYOUT
%  - you can give the name of an ascii layout file with extension *.lay
%  - you can give the name of an electrode file
%  - you can give an electrode definition, i.e. "elec" structure
%  - you can give a gradiometer definition, i.e. "grad" structure
% If you do not specify any of these and the data structure contains an
% electrode or gradiometer structure, that will be used for creating a
% layout. If you want to have more fine-grained control over the layout
% of the subplots, you should create your own layout file.
%
% See also FT_SINGLEPLOTER, FT_MULTIPLOTER, FT_SINGLEPLOTTFR, FT_MULTIPLOTTFR,
% FT_TOPOPLOTTFR, FT_PREPARE_LAYOUT

% Undocumented options:
%
% It is possible to use multiple highlight-selections (e.g.: multiple
% statistical clusters of channels) To do this, all the content of
% the highlight-options (including cfg.highlight) should be placed
% in a cell-array (even if the normal content was already in a
% cell-array). Specific marker settings (e.g. color, size) are defaulted
% when not present.
%
% Example (3 selections):
% cfg.highlight          = {'labels', 'labels', 'numbers'}
% cfg.highlightchannel   = {{'MZF03','MZC01','MRT54'}, [1:5], 'C*'}
% cfg.highlightsymbol    = {'o',[],'+'}        % the empty option will be defaulted
% cfg.highlightcolor     = {'r',[0 0 1]};      % the missing option will be defaulted
% cfg.highlightsize      = [];                 % will be set to default, as will the missing cfg.highlightfontsize
%
% Other options:
% cfg.labeloffset (offset of labels to their marker, default = 0.005)

% Copyright (C) 2005-2020, F.C. Donders Centre
%
% 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/>.
%
% $Id$

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% DEVELOPERS NOTE: This code is organized in a similar fashion for multiplot/singleplot/topoplot
% and for ER/TFR and should remain consistent over those 6 functions.
% Section 1: general cfg handling that is independent from the data
% Section 2: data handling, this also includes converting bivariate (chan_chan and chancmb) into univariate data
% Section 3: cfg handling that depends on the data
% Section 4: actual plotting
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%% Section 1: general cfg handling that is independent from the data

% these are used by the ft_preamble/ft_postamble function and scripts
ft_revision = '$Id$';
ft_nargin   = nargin;
ft_nargout  = nargout;

% do the general setup of the function
ft_defaults
ft_preamble init
ft_preamble debug
ft_preamble loadvar varargin
ft_preamble provenance varargin

% the ft_abort variable is set to true or false in ft_preamble_init
if ft_abort
  return
end

% this is needed for the figure title
if isfield(cfg, 'dataname') && ~isempty(cfg.dataname)
  dataname = cfg.dataname;
elseif isfield(cfg, 'inputfile') && ~isempty(cfg.inputfile)
  dataname = cfg.inputfile;
elseif nargin>1
  dataname = arrayfun(@inputname, 2:nargin, 'UniformOutput', false);
else
  dataname = {};
end

% make sure figure window titles are labeled appropriately, pass this onto the actual plotting function
cfg.funcname = mfilename;
cfg.dataname = dataname;

% prepare the layout, this should be done only once
tmpcfg = keepfields(cfg, {'layout', 'channel', 'rows', 'columns', 'commentpos', 'skipcomnt', 'scalepos', 'skipscale', 'projection', 'viewpoint', 'rotate', 'width', 'height', 'elec', 'grad', 'opto', 'linecolor', 'showcallinfo', 'trackcallinfo', 'trackusage', 'trackdatainfo', 'trackmeminfo', 'tracktimeinfo', 'checksize'});
cfg.layout = ft_prepare_layout(tmpcfg, varargin{1});

% call the common function that is shared between ft_topoplotER and ft_topoplotTFR
cfg = topoplot_common(cfg, varargin{:});

% remove this field again, it is only used for figure labels
cfg = removefields(cfg, 'funcname');

% do the general cleanup and bookkeeping at the end of the function
ft_postamble debug
ft_postamble previous varargin
ft_postamble provenance
ft_postamble savefig

% add a menu to the figure, but only if the current figure does not have subplots
menu_fieldtrip(gcf, cfg, false);

if ~ft_nargout
  % don't return anything
  clear cfg
end
