GUI - Updating a figure pseudo real-time and stopping on mouse-click

Hi all,

On my GUI I'm attempting to write a callback function that runs a loop triggered by a button press and ends when the mouse is clicked. I have been able to code the trigger of a loop that 'continuously' updates a figure for a pre-specified number of iterations. Essentially, there is a callback function with a loop triggered at a button press on the GUI.

I would like to add code that prematurely ends the loop at a mouse press. I have looked at using the "WindowsbuttondownFcn" but could not successfully implement to end the loop. What approach should I take? Any help is greatly appreciated in advance! The current callback function is below:

function uipanel1_SelectionChangeFcn(hObject, eventdata, handles)
switch get(eventdata.NewValue,'Tag') % Get Tag of selected object.
    case 'togglebutton1'
        % Code for when radiobutton1 is selected.

          axes(handles.axes1)
          set (gcf, 'WindowButtonMotionFcn', @mouseMove)
          y = 0;handles.stop = 0;
          while y <15
              y = y+1;
              pause(0.2)
              point = get(gcf,'currentpoint');
              [point flag] = convertpoint(point(1),handles);
  %           Do not run if cursor outside of figure window
              if flag == 0
                  updateplots2(handles,point) 
              end
          end
  End

Answer 1

[Daniel Shub]

The WindowsbuttondownFcn seems like the correct approach. You need to do something in the WindowsbuttondownFcn callback which can then be checked from the uipanel1_SelectionChangeFcn loop.

From the command line or the function that builds your gui:

hfig = gcf;
set (hfig, 'WindowButtonDownFcn', @(src, evt)(setappdata(hfig, 'mouseclick', true)));
setappdata(hfig, 'mouseclick', false);

Then modify your while loop to include:

if getappdata(gcf, 'mouseclick')
  break;
end

[Brandon]

Thank you for the quick responses.

I am having trouble passing arguments from the function called by the WindowbuttondownFcn callback. I added the code

flag2 = set (gcf, 'WindowButtonDownFcn', @mouseclick)

and defined the function mouseclick as follows:

function [flag2] = mouseclick (hObject, handles)

flag2 = 1;

end

So that the new complete code looks like:

function uipanel1_SelectionChangeFcn(hObject, eventdata, handles)

% hObject handle to the selected object in uipanel1

% eventdata structure with the following fields (see UIBUTTONGROUP)

% EventName: string 'SelectionChanged' (read only)

% OldValue: handle of the previously selected object or empty if none was selected

% NewValue: handle of the currently selected object

% handles structure with handles and user data (see GUIDATA)

switch get(eventdata.NewValue,'Tag') % Get Tag of selected object.

case 'togglebutton1'

% Code for when radiobutton1 is selected.

flag2 = 0;

axes(handles.axes1)

set (gcf, 'WindowButtonMotionFcn', @mouseMove)

set(gcf, 'WindowButtonDownFcn', @mouseclick)

y = 0;handles.stop = 0;

while y <15

y = y+1;

pause(0.2)

fprintf('%d',flag2)

point = get(gcf,'currentpoint');

[point flag] = convertpoint(point(1),handles);

% Do not run if cursor outside of figure window

if flag == 0

updateplots2(handles,point)

end

end

case 'togglebutton2'

% Code for when radiobutton2 is selected.

disp('hi')

otherwise

% Code for when there is no match.

end

end

function [flag2] = mouseclick (hObject, handles)

flag2 = 1;

end

This is probably my lack of clear understanding of the function callback architecture, but I cannot use the variable 'flag2' outside of the 'mouseclick' function - This is what I'm attempting to use to 'break' my main loop upon a mouse click.

[Daniel Shub]

See my edit (which allows code formatting). I am passing the data about if a mouse click occurred via the application data of the figure.

Answer 2

[Fangjun Jiang]

Instead of a mouse click (it might accidentally happen), you might want to consider adding a push button (or toggle button) on your GUI to stop it. I saw several posts recently. Jan Simon's answer in this post should provide sufficient leads.

http://www.mathworks.com/matlabcentral/answers/14180-cancel-running-program-with-crtl-c-is-it-possible-to-recover-the-processed-data

[Daniel Shub]

The code is tracking the mouse position, so I would guess that moving the mouse to a button would screw things up.

[Fangjun Jiang]

Okay, then use the WindowsbuttondownFcn suggested by Daniel. I guess you can add a hidden toggle button (or anything else) in the GUI. In your WindowsbuttondownFcn callback, change the value. In your uipanel1_SelectionChangeFcn callback, combine that value check with your y<15 check in the condition for while-loop.

Answer 3

[Daniel Shub]

With a little work you should be able to get your approach to work. A sexier and in my opinion better way to approach it is with a timer

doc timer

Basically you define a function that does:

function timercallback(src, evt, hfig, handles)
  point = get(hfig, 'currentpoint');
  [point, flag] = convertpoint(point(1), handles);
  if flag == 0
    updateplots2(handles, point) 
  end
end

then you build a timer

htimer = timer('ExecutionMode', 'fixedRate', 'Period', 0.2, 'StartDelay', 0.2, 'StartFcn', @(src, evt)timercallback(src, evt, gcf, handles), 'TasksToExecute', 15, 'TimerFcn', @(src, evt)timercallback(src, evt, gcf, handles));

Then your toggle button starts the timer and the WindowbuttondownFcn can stop the timer.