function ret = spm_ov_rgb(varargin)
% RGB overlays - plugin for spm_orthviews
% A shorthand to overlaying the absolute value of three different images
% onto a displayed image in colours red, green and blue. The overlay images
% are optionally masked and multiplied with a scaling image. The displayed
% overlay images are the absolute value of the given overlays.
%
% This routine is a plugin to spm_orthviews. For general help about
% spm_orthviews and plugins type
%             help spm_orthviews
% at the MATLAB prompt.
%__________________________________________________________________________
% Copyright (C) 2012 Wellcome Trust Centre for Neuroimaging

% Volkmar Glauche
% $Id: spm_ov_rgb.m 4996 2012-10-11 18:28:37Z guillaume $

global st;
if isempty(st)
    error('rgb: This routine can only be called as a plugin for spm_orthviews!');
end

if nargin < 2
    error('rgb: Wrong number of arguments. Usage: spm_orthviews(''rgb'', cmd, volhandle, varargin)');
end

cmd = lower(varargin{1});
volhandle = varargin{2};

switch cmd

    %-Context menu and callbacks
    %----------------------------------------------------------------------
    case 'context_menu'
        item0 = uimenu(varargin{3}, 'Label', 'RGB overlays');
        item1 = uimenu(item0, 'Label', 'Add', 'Callback', ...
            sprintf('%s(''context_init'', %d);', mfilename, volhandle), ...
            'Tag',['RGB_0_', num2str(volhandle)]);
        item1 = uimenu(item0, 'Label', 'Help', 'Callback', ...
            sprintf('spm_help(''%s'');', mfilename));

    case 'context_init'
        Finter = spm_figure('FindWin', 'Interactive');
        spm_input('!DeleteInputObj',Finter);
        [Vqfnames,sts] = spm_select(3, 'image',...
            'RGB components images (such as eigenvectors)');
        if ~sts, return; end
        Vq = spm_vol(Vqfnames);
        Vfafname = spm_select([0 1],'image','Scaling image (FA) (optional)');
        Vfa = spm_vol(Vfafname);
        Vmaskfname = spm_select([0 1],'image','Mask image (optional)');
        Vmask = spm_vol(Vmaskfname);
        spm('pointer','watch');
        Vamq = rmfield(Vq,'private');
        for k=1:3
            [p,n,e,v] = spm_fileparts(Vq(k).fname);
            sel = 2*isempty(Vmask)+isempty(Vfa);
            switch(sel)
                case 0, %both Vmask and Vfa set
                    Vamq(k).fname=fullfile(p,['abs_msk_fa_' n e v]);
                    spm_imcalc([Vq(k) Vfa Vmask],Vamq(k),'abs(i1.*i2.*i3)',{[],1,[]});
                case 1, %only Vmask set
                    Vamq(k).fname=fullfile(p,['abs_msk_' n e v]);
                    spm_imcalc([Vq(k) Vmask],Vamq(k),'abs(i1.*i2)',{[],1,[]});
                case 2, %only Vfa set
                    Vamq(k).fname=fullfile(p,['abs_fa_' n e v]);
                    spm_imcalc([Vq(k) Vfa],Vamq(k),'abs(i1.*i2)',{[],1,[]});
                case 3, %nothing set
                    Vamq(k).fname=fullfile(p,['abs_' n e v]);
                    spm_imcalc(Vq(k),Vamq(k),'abs(i1)',{[],1,[]});
            end
        end
        spm_orthviews('addcolouredimage',volhandle,Vamq(1),[1 0 0]);
        spm_orthviews('addcolouredimage',volhandle,Vamq(2),[0 1 0]);
        spm_orthviews('addcolouredimage',volhandle,Vamq(3),[0 0 1]);
        spm_orthviews('redraw');

        spm_input('!DeleteInputObj',Finter);
        spm('pointer','arrow');
        
    case 'redraw'
        % Do nothing
        
    otherwise
        fprintf('spm_orthviews(''rgb'', ...): Unknown action %s', cmd);
end