MATLAB: Slider is not working in the GUI

guiguideimage processingmousescrollslider

I have created a GUI consisted of 4 axes, a push button and a slider. Although, the slider commands (callbacks, uicontrols, guidata etc) including the mouseScroll function, are perfectly working, because they have been tested to a different figure (not my GUI) consisted of a single hFig and an axes1 and it perfectly work, but when I try to implement the same commands to my GUI it fails.

You will notice to the m files I attach, that I have placed the same commands over and over again to almost all the relative callback functions (slider1_Callback, mouseScroll, loadButton, etc) because they were asking for the variables to be stated.

Any help on this?

Best Answer

You are creating a new slider inside the callback of the slider:

handles.SliderFrame = uicontrol('Style','slider','Position',[60 20 400 50], ...
                            'Min',1,'Max',NumFrames,'Value',1, ...
                            'SliderStep',[1/NumFrames 2/NumFrames], ...
                            'Callback',@slider1_Callback);

This hides the formerly existing sliders and sets the slider value to 1 for each call.

Importing the list of files in all slider callbacks is a waste of time in addition.

Solution: Create the slider once only, either in GUIDE or in the OutputFcn (where it is done now already also). Then omit the re-creation by uicontrol.

I suggest to call the slider1_callback from the mouseScroll function.

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MATLAB: How to control two axes over a single slider

Your sliders are in exactly the same screen position. You create slider2 second so it is on top. Clicks go to the top item only in most circumstances. So the slider on the bottom, slider1, is never receiving clicks to know to update.

MATLAB: How to connect GUI sliders to image analysis

This is how I would modify your gui to get the image erodeII and slider values into pushbutton3_Callback

...
% --- Executes on button press in pushbutton1.
function pushbutton1_Callback(hObject, eventdata, handles)
...
handles.erodedII = imerode(erodedI,se);
axes(handles.axes2)%%%%%%%%%
imshow(handles.erodedII);
...
L=bwlabel(handles.erodedII);
% Update handles structure



guidata(hObject, handles);
...
% --- Executes on slider movement.


function slider1_Callback(hObject, eventdata, handles)
...
    handles.slide_thresh=get(hObject,'value');
    % Update handles structure
    guidata(hObject, handles);
    ...
% --- Executes on slider movement.
function slider2_Callback(hObject, eventdata, handles)
...
    handles.slide_min=get(hObject,'value');
    % Update handles structure
    guidata(hObject, handles);
    ...
% --- Executes on slider movement.
function slider3_Callback(hObject, eventdata, handles)
...
    handles.slide_max=get(hObject,'value');
    % Update handles structure
    guidata(hObject, handles);
    ...
        
...
% --- Executes on button press in pushbutton3.
function pushbutton3_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton3 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
img = handles.erodedII;
thresh = handles.slide_thresh;
slide_min = handles.slide_min;
slide_max = handles.slide_max;

In pushbutton3, you do not have to assign fields on the handles structure to a variable in order to use them. I just did that to demonstrate how to access them.

Best Answer

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MATLAB: How to connect GUI sliders to image analysis

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