Program runtime suggests that the function is too deeply nested

function varargout = threshold_OutputFcn(hObject, eventdata, handles)

% varargout cell array for returning output args (see VARARGOUT);

% hObject handle to figure

% eventdata reserved - to be defined in a future version of MATLAB

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

global g_MaxThreshold;

global g_MinThreshold;

global g_LastThresholdedColorBand;

varargout{1} = g_MinThreshold;

varargout{2} = g_MaxThreshold;

varargout{3} = g_LastThresholdedColorBand;

% handles.figMainWindow.Color = [0, 0, .25];

% g = gcf;

% g.WindowState = 'maximized';

%disp('Exited threshold macro');

%| ABOUT CALLBACKS:

%| GUIDE automatically appends subfunction prototypes to this file, and

%| sets objects' callback properties to call them through the FEVAL

%| switchyard above. This comment describes that mechanism.

%|

%| Each callback subfunction declaration has the following form:

%| <SUBFUNCTION_NAME>(H, EVENTDATA, HANDLES, VARARGIN)

%|

%| The subfunction name is composed using the object's Tag and the

%| callback type separated by '_', e.g. 'slider2_Callback',

%| 'threshold_CloseRequestFcn', 'axis1_ButtondownFcn'.

%|

%| H is the callback object's handle (obtained using GCBO).

%|

%| EVENTDATA is empty, but reserved for future use.

%|

%| HANDLES is a structure containing handles of components in GUI using

%| tags as fieldnames, e.g. handles.figMainWindow, handles.slider2. This

%| structure is created at GUI startup using GUIHANDLES and stored in

%| the figure's application data using GUIDATA. A copy of the structure

%| is passed to each callback. You can store additional information in

%| this structure at GUI startup, and you can change the structure

%| during callbacks. Call guidata(h, handles) after changing your

%| copy to replace the stored original so that subsequent callbacks see

%| the updates. Type "help guihandles" and "help guidata" for more

%| information.

%|

%| VARARGIN contains any extra arguments you have passed to the

%| callback. Specify the extra arguments by editing the callback

%| property in the inspector. By default, GUIDE sets the property to:

%| <MFILENAME>('<SUBFUNCTION_NAME>', gcbo, [], guidata(gcbo))

%| Add any extra arguments after the last argument, before the final

%| closing parenthesis.

Answer 1

[Namnendra]

Hi,

The error message you're encountering suggests that your function is too deeply nested, which usually refers to excessive recursion or a complex nested function structure. However, from the code snippet you provided, it seems like a straightforward function. There might be some other parts of your code that are causing this issue, but let's address a few potential areas of improvement and debugging steps:

Suggestions for Improvement

1. Global Variables:

- Global variables can lead to difficult-to-trace bugs and should be used sparingly. If possible, consider passing these variables as input arguments to your function or storing them in the `handles` structure.

2. Code Clarity:

- Ensure that your code is not unnecessarily complex. If there are other functions or callbacks that call each other in a way that might lead to deep nesting, consider refactoring them.

3. Error Checking:

- Ensure that other parts of your code are not recursively calling functions unintentionally.

4. Use `guidata`:

- Instead of using global variables, you can store your variables in the `handles` structure, which is more common in MATLAB GUI applications. Refer to following link to understand more:-

https://www.mathworks.com/help/matlab/ref/guidata.html?s_tid=doc_ta

 function varargout = threshold_OutputFcn(hObject, eventdata, handles)
        % Retrieve values from handles structure
        minThreshold = handles.g_MinThreshold;
        maxThreshold = handles.g_MaxThreshold;
        lastThresholdedColorBand = handles.g_LastThresholdedColorBand;
        
        % Set output variables
        varargout{1} = minThreshold;
        varargout{2} = maxThreshold;
        varargout{3} = lastThresholdedColorBand;
 end

5. Check Other Parts of the GUI Code:

- The issue might not be in this function. Check other callback functions to ensure there is no excessive recursion or deeply nested function calls.

Debugging Steps

1. Profile the Code:

- Use MATLAB’s profiler (`profile on; ...; profile viewer;`) to identify where the nesting or recursion might be happening.

2. Simplify the GUI:

- Temporarily remove or comment out parts of your GUI code to see if the problem persists. This can help isolate the problematic section.

3. Check for Recursion:

- Look for any functions that might be calling themselves either directly or indirectly through other functions, leading to deep nesting.

4. Review GUIDE Callbacks:

- Ensure that the callbacks generated by GUIDE are not creating unintended nested calls.

By addressing these suggestions and following the debugging steps, you should be able to resolve the issue with deeply nested functions in your MATLAB GUI application. If the problem persists, consider providing more context or additional code snippets for further assistance.

Thank you.