creating a line cursor in app designer

Hi!

assume I create a signal and show it over an UIiAxes in matlab app designer.

is there a way to create a retangle cursor or line cursor using the imaged.roi.rectangle object / imaged.roi.rectangle object ?

something like the next function:

https://www.mathworks.com/help/dsp/ref/cursormeasurementsconfiguration.html

a full code is needed, if is possible.

thanks

[Adam Danz]

Could you elaborate on what you mean by cursor? Would the line/rectangle follow the mouse cursor?

[David]

Yes, If we use rectangle, i want that only the vertical lines would be dragged after the mouse ). The same for 2 lines objects.

Answer 1

[Sachin]

Hi

I understand that you want to create a line cursor for an app designer.

You can use the Callback function in MATLAB to achieve this. There are several callback functions in MATLAB uifigure that you can help you.

1. WindorButtonMotionFcn – This callback function executes whenever the user moves the pointer within the UI figure.
2. ButtonDownfcn - This callback executes whenever the user clicks on the mouse button

fig = uifigure();
gl = uigridlayout(fig,[2 2]);

ax = uiaxes(gl);

hline = line(ax, [5 5], ax.YLim, 'Color', 'r');
% 
fig.WindowButtonMotionFcn = @(fig, eve) btnCb(fig, eve, ax, hline);
function btnCb(~, ~, ax_up, l_h)
    x = ax_up.CurrentPoint(1, 1)
    if (ax_up.XLim(1) < x) && (x < ax_up.XLim(2))
        l_h.XData = [x,x];
    end
end

Referring to this MATLAB Answer page might be helpful to you:

https://in.mathworks.com/matlabcentral/answers/603793-show-mouse-position-in-another-subplot

Hope this helps you