Continuous updating of GUI plotting

I am preparing a gui where the visibility of plots are controlled by checkbox selection in two different axes. Additionally, the user should select the Y vector from a popupmenu. The code is working fine (it could be more elegant) but I have issues with refreshing the plot automatically. At present, If I plot and subsequently select a different Y values from the popupmenu I have to uncheck and recheck the checkmark for the changes to take place in the plot. How can I make the GUI refresh the plot automatically if it is selected (checkmark). Any help is much appreciated:

Here is my code:

% --- Executes on pushbutton1.
function pushbutton1_Callback(hObject, eventdata, handles)
X=[1 2 3 4]
Y1=[10 20 30 40]
Y2=[-1 -2 -3 -4]
handles.X=X;
handles.Y1=Y1;
handles.Y2=Y2;
guidata(gcbo, handles);
UnitFcn(handles)

% --- checkbox function on/off
function C = OnOffStr(D)
OffOn = {'off', 'on'};
L     = (D ~= 0) + 1;  % 0/FALSE => 1, anything else => 2
if length(L) == 1
  C = OffOn{L};   % Reply a string
else
  C = OffOn(L);   % Reply a cell string
end

function UnitFcn(handles)
Y1=handles.Y1;

for p = 1:numel(plotdata)

      Unit = get(handles.popupmenu1,'Value');
      if (Unit==1)
      Y(:,p)=Y1(:,p);

      elseif (Unit==2)%
      Y(:,p)=Y1(:,p)*100;

      end         
  end

handles.Y=Y;
guidata(gcbo, handles);
PlotFcn(handles)

function PlotFcn(handles)
X=handles.X;
Y=handles.Y;
Z=handles.Y2;

%Plot in Axes 1
set(handles.axes1, 'NextPlot', 'add');
    handles.plot1 = plot(X,Y,'visible','off','LineWidth',2, ...
                            'color', [0 0 0],'linestyle', '--', 'parent', handles.axes1);    

%Plot in Axes 2
set(handles.axes2, 'NextPlot', 'add');    
    handles.plot2 = plot(X,Y2,'visible','off','LineWidth',2, ...
                            'color', [0 0 0],'linestyle', '--', 'parent', handles.axes2);

guidata(gcbo, handles);

% --- Executes on button press in checkbox1.
function checkbox1_Callback(hObject, eventdata, handles)
set(handles.plot1, 'Visible', OnOffStr(get(hObject,'Value')));

% --- Executes on button press in checkbox1.
function checkbox1_Callback(hObject, eventdata, handles)
set(handles.plot2, 'Visible', OnOffStr(get(hObject,'Value')));

% --- Specify unit in popupmenu1.
function popupmenu1_Callback(hObject, eventdata, handles)
UnitFcn(handles)

function popupmenu1_CreateFcn(hObject, eventdata, handles)
if ispc && isequal(get(hObject,'BackgroundColor'), get(0,'defaultUicontrolBackgroundColor'))
    set(hObject,'BackgroundColor','white');
end

This is a simplified code and the "for p = 1:numel(plotdata)" refer to a matrix where I have ~30 different plots.

[Geoff Hayes]

JB - are you saying that the

 function popupmenu1_Callback(hObject, eventdata, handles)
 UnitFcn(handles)

is not being called when the user chooses something from the popup menu? Because this callback has the code to update the plot (I'm assuming that is what UnitFcn is doing...)

[JB]

I can solve it if I include this code in the PlotFcn:

for i=1:1:numel(X(1,:)) Checked(i,1) = get(handles.(sprintf('checkbox%d',i)),'value'); if (Checked(i,1)==1) set(handles.plot(i), 'Visible', 'on') set(handles.plot(i), 'Visible', 'on') end end

but I am not sure this is the best solution?? It takes some time to run 30 plots with this code.

[Adam]

As an aside: If you are continuously updating a plot it is far better to update the XData and YData of the same plotted object rather than keep plotting a new one.

[JB]

@Geoff. The UnitFcn is called appropriately and the X and Y values are recalculated according to the UnitFcn. But I have to uncheck and recheck the checkbox to make the new plot visible.

[JB]

@Adam. So the way the code is working now is the Y data is recalculated when the popupmenu is selected. Is this what you mean, or how can I change it within the XData and YData of the same plotted object. Thanks

[Adam]

handles.plot1

is the handle to the plot object you created. Instead of just keep replotting it you can use

handles.plot1.YData = ...

to update it with far better performance if you rework your code. Usually I do this by creating an empty plot handle initially then just using an if statement - if the handle is empty then do the plot instruction, else only update the YData (and any other properties that may have changed) of the existing plot.