function h = dataSlider(N,fcnHan)
% function h = dataSlider(N,fcnHan)
%
% Creates a gui scrollbar for inspection of data.
% N must be integer number of data slices to step thru
% fcnHan is handle to external function
% external function must have form: fcnHan(v)

% blocks subsequent callbacks until finished

h.f = figure('Menubar','none','Toolbar','none','Name','Slider',...
    'NumberTitle','off','Units','normalized',...
    'Position',[.466 .118 .389 .049]);

h.u = uicontrol('Style','slider','Units','normalized','Position',[.04 .38 .92 .4],...
    'Value',1,'Min',1,'Max',N,'SliderStep',[1/(N-1) 1/(N-1)],...
    'Callback',{@dataSliderFcn,fcnHan},'BusyAction','cancel');

set(h.f,'HandleVisibility','off')

    function dataSliderFcn(obj,evt,fcnHan)
        v = round(get(h.u,'Value'));
        disp('updating....')
        fcnHan(v);
        disp('done')
    end
end