Change imellipse position when the string in edit-text uicontrol is updated.

Hi All,

I rather have a strange requirement. I display an image in an axes of a GUI figure created using GUIDE. I use imellipse to select a circle in the image. Although imellipse allows me to resize it by dragging the boundaries, I also want to resize it based on the vector entered in the uicontrol edit-text.

Essentially, when imellipse is run, a popup window with edit-text uicontrol is created with some initial position vector of the ellipse. I want to change the position vector in the edit-text which gets reflected in the position of ellipse in the image and also that the resizing of imellipse updates the vector in edit-text.

I was able to do the latter part using the following lines of code (under a function called crop) -

EllipseHandle = imellipse(gca,[0.25*width 0.25*height 0.5*width 0.5*height]);  
addNewPositionCallback(EllipseHandle,@(p) set(handles.CroppingVector,'String',num2str(p,3)));

CroppingVector is the tag for the edit-text uicontrol.

Now, I want to update the position of the ellipse when the vector in edit-text is changed. I am able to read the updated vector in the callback function for edit-text which looks like this:

function CroppingVector_Callback(hObject, eventdata, handles)
% hObject    handle to CroppingVector (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
Pos = str2num(get(handles.CroppingVector,'String'));

However, I am having difficulty trying to understand how to update the ellipse position. I tried using (immediately after above line of code in the callback function for edit-text)

setConstrainedPosition(EllipseHandle,Pos);

But I get the following error

Undefined function 'setConstrainedPosition' for input arguments of type 'double'.

Obviously, EllipseHandle is not recognized. Can anyone please suggest a working solution to my problem?

-- Thanks, Ram.