MATLAB: How to get the minimum and maximum value of the xaxis when I zoom in on a plot

axescallbackguiguideplotzoom in

 Is it possible to define a callback when I zoom in on the plot and get the minimum and maximum x values from the plot? Kindly request you to give an example.

Thanks in Advance.

Best Answer

Have you looked at the xlim() function?

Related Solutions

MATLAB: How to automtically update editText box with ‘new axes limit’ when Zoom tool has changed the axes limit

betty - I don't think that you need an event listener, you just need the means at which to access the handle to the edit text control. From the above example, you haven't indicated how you are using this code or how you have created your GUI, but let's assume that you have done so with GUIDE. Suppose that you have an axes, a (say) checkbox to enable or disable the zoom, and a text box to display the axes limits. Then in the checkbox callback we enable or disable the zoom as

 function checkbox1_Callback(hObject, eventdata, handles)
 if get(hObject,'Value') == 1
    if ~isfield(handles,'hZoom')
        handles.hZoom = zoom;
        set(handles.hZoom,'ActionPostCallback',@zoomPostCallback);
        guidata(hObject,handles);
    end
    set(handles.hZoom,'Enable','on');
 else
    if isfield(handles,'hZoom')
        set(handles.hZoom,'Enable','off');
    end
 end

In the zoom post action callback we do

 function zoomPostCallback(hObject,event)
 handles = guidata(hObject);
 if isfield(handles,'text1')
    set(handles.text1,'String',num2str(get(handles.axes1,'XLim')));
 end

In the above, we use the hObject input parameter to get the handles structure (via guidata) which will have the handle to the text1 control. We update that control using the new limits of axes1. See the attached for a simple example.

MATLAB: “Warning: Error during Mode Callback” when calling functions in Zoom ActionPostCallback

I have found a work around for this bug. By using a while loop and the uiwait, uiresume commands I was able to get the graphs to redraw after the zoom event. Here is the fix to my code:

% --------------------------------------------------------------------

function toolbar_zoomin_OnCallback(hObject, eventdata, handles)
% hObject    handle to toolbar_zoomin (see GCBO)

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

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

global zoom_use current_object stop_updating;
zoom_use=0;
stop_updating = 0;
h = zoom(handles.del_pwr);
h = zoom(handles.gmag);
set(h,'ActionPostCallback',@mypostcallback);
set(h,'Enable','on');
current_object = gcf;
while zoom_use ==0
    uiwait(gcf);
    pushbutton_redrawsmithchart_Callback(hObject, eventdata, handles)
    if stop_updating == 1
        break;
    end
end
% ----occurs after mouse button up for zoom function
function mypostcallback(obj,evd)
global newLim zoom_use current_object;
newLim = get(evd.Axes,'XLim');
disp(sprintf('The new X-Limits are [%.2f %.2f].',newLim));
zoom_use=1;
axis 'auto y';
disp(zoom_use);
uiresume(current_object);
% --------------------------------------------------------------------
function toolbar_zoomin_OffCallback(hObject, eventdata, handles)
% hObject    handle to toolbar_zoomin (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
global stop_updating;
zoom off;
stop_updating = 1;

In addition, in the last line of my redrawsmithchart function I have put the line:

zoom_use= 0;

to reset for the while loop.

There are probably more efficient ways of solving this but none that I can come up with. This also doesn't answer my original question of why I was receiving the error described above.

Best Answer

Related Solutions

MATLAB: How to automtically update editText box with ‘new axes limit’ when Zoom tool has changed the axes limit

MATLAB: “Warning: Error during Mode Callback” when calling functions in Zoom ActionPostCallback

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