function g_arithmetic(currPanel,varargin)   
    % This callback is called whenever the user selects an arithmetic block.
        
        global guiFontSize params functionName selBlocks %#ok<NUSED>
        panelDimens = get(currPanel, 'Position');
        backColor   = get(currPanel, 'BackgroundColor');

        delete(findobj(gcf,'Parent',currPanel))
        guiFontSize = getappdata(0, 'ltpda_gui_fontsize')-1;
        lineSpacing = 30 * guiFontSize/10;

        paramcommand = get_param(gcbh,'Description');
      % noParamsReq=0;
        if isempty(paramcommand)
            paramcommand = g_RetrievePlist('arithmetic');
            selBlocks = utils.prog.gcbsh;
            for kk=1:length(selBlocks)
                set_param(selBlocks(kk),'Description',paramcommand);
            end
        end
        eval(paramcommand)

        logosize = [30,30];
        dimension = [panelDimens(3)-135 , 15 , logosize];
        logo = axes('Parent',currPanel,'Units','pixels','Position',dimension);
        image(imread('buttonyes.jpg'),'Parent',logo);
        axis(logo,'off');
      % Apply button
        uicontrol('Parent',currPanel,'Units','pixels','Position',[panelDimens(3)-100 20 80 guiFontSize*20/10],'HorizontalAlignment','right','FontSize',guiFontSize,'String','Apply','Visible','on','Callback', @ApplyArithCallback,'DeleteFcn',{@ApplyArithCallback,0},'Tag','apply','Enable','off','Style','pushbutton');

        uicontrol('Parent',currPanel,'BackgroundColor',backColor,'Units','pixels','Position',[20 panelDimens(4)-55 100 20],'String','List of input:','HorizontalAlignment','left','FontSize',guiFontSize,'Visible','on','Style','text');  
        y = nparams(params);
        for i=1:y
           uicontrol('Parent',currPanel,'BackgroundColor',backColor,'Units','pixels','Position',[7 panelDimens(4)-lineSpacing*(i+2)-4 8 20],'String','>','FontSize',guiFontSize,'FontWeight','Bold','Visible','on','Style','text');
           uicontrol('Parent',currPanel,'Units','pixels','Position',[20 panelDimens(4)-lineSpacing*(i+2) 100 20],'String',lower(params.params(i).key),'FontSize',guiFontSize,'Visible','on','Enable','on','UserData',i,'Callback',@g_editNameCallback,'Style','edit');
         % Remove input button
           if i>1
              uicontrol('Parent',currPanel,'Units','pixels','Position',[125 panelDimens(4)-lineSpacing*(i+2) 20 20],'String','-','Visible','on','Enable','on','Callback', @g_RemParamCallback,'UserData',i,'Style','pushbutton');
           end
        end
      % Add input button
        uicontrol('Parent',currPanel,'Units','pixels','Position',[20 panelDimens(4)-40-lineSpacing*(y+2) 20 20],'String','+','Visible','on','Enable','on','Callback', @g_AddParamCallback,'UserData','input','Style','pushbutton');

      % Output name:
        uicontrol('Parent',currPanel,'BackgroundColor',backColor,'Units','pixels','Position',[20 panelDimens(4)-47-lineSpacing*(y+3) 140 20],'String','Output name:','HorizontalAlignment','left','FontSize',guiFontSize,'Visible','on','Style','text');
        outName = get(gcbh,'UserData');
        if isempty(outName), outName = get(gcbh,'Name'); end
        uicontrol('Parent',currPanel,'Units','pixels','Position',[20 panelDimens(4)-40-lineSpacing*(y+4) 100 20],'String',outName,'FontSize',guiFontSize,'Visible','on','Enable','on','UserData',i,'Callback','set(gcbh,''UserData'',get(gco,''String''));set(gcbh,''UserDataPersistent'',''on'')','Style','edit');

      % 'Type in the equation' text
        uicontrol('Parent',currPanel,'BackgroundColor',backColor,'Units','pixels','Position',[180 panelDimens(4)-50 400 20],'String','Type in the equation, using as an example:','HorizontalAlignment','left','FontSize',guiFontSize,'Visible','on','Style','text');  
      % Example edit field
        uicontrol('Parent',currPanel,'TooltipString','This in an example of how to type in an equation','BackgroundColor',[0.97 0.97 0.97],'Units','pixels','Position',[180 panelDimens(4)-72 500 20],'String','(alpha+beta)/2+alpha^2','FontSize',guiFontSize,'Visible','on','Enable','on','Callback','set(gco,''String'',''(alpha+beta)/2+alpha^2'')','Style','edit');

      % 'output =' text
        uicontrol('Parent',currPanel,'BackgroundColor',backColor,'Units','pixels','Position',[180 panelDimens(4)-100 400 20],'String','Output =','HorizontalAlignment','left','FontSize',guiFontSize,'Visible','on','Style','text');  
      % Main edit field
        eqString = get_param(gcbh,'MaskDescription');
        if numel(eqString)>16 && strcmp(eqString(1:17),'Arithmetic block:'), eqString = ''; end
        uicontrol('Parent',currPanel,'BackgroundColor',[0.9 0.9 0.9],'Units','pixels','Position',[180 panelDimens(4)-300 500 200],'String',eqString,'Max',2,'FontSize',guiFontSize,'Visible','on','Enable','on','Tag','equationField','Callback','set(findobj(''Tag'',''apply''),''Enable'',''on'');','Style','edit');

        
    %----------------------------------------------------------------------
    function ApplyArithCallback(varargin)
    % Whenever the user clicks on the 'Apply' button for the arithmetic
    % block.
    
        eqField = findobj(gcf,'Tag','equationField');
        eq = get(eqField,'String');
        if ~isempty(eq)
            if numel(eq)>40, eq(1:end-25) = []; eq = ['...',eq]; end
            for nn=1:length(selBlocks)
                set_param(selBlocks(nn),'MaskDescription',get(eqField,'String'));
                set_param(selBlocks(nn),'AttributesFormatString',eq);
            end
        else
            eqString = get_param(gcbh,'MaskDescription');
            if numel(eqString)>16 && strcmp(eqString(1:17),'Arithmetic block:'), eqString = ''; end
            set(eqField,'String',eqString);
        end
    
    end
    %----------------------------------------------------------------------
        
    end
    %----------------------------------------------------------------------