How to zoom on the mouse pointer

Hi, I'm using the app designer and I need to select points from a plot. To increase the accuracy of the selected points I would like that after clicking a button in the app it activates a zoomed view of the pointer in a UIAxes next to the plot (where there is the "PREVIEW" label).

How can I achieve this function? Thanks, Luca.

Answer 1

[Cameron]

I'll post how I was able to do what you're asking. For your application, there may be a slight difference because you are using a picture rather than a plot in your big UIAxes, but this should get you 95% of the way there.

% Window button motion function: UIFigure
function UIFigureWindowButtonMotion(app, event)
    PointerLocation = get(app.UIFigure,'CurrentPoint'); %location of pointer

    axisYcoords = [app.UIAxes.InnerPosition(2),...
        app.UIAxes.InnerPosition(2) + app.UIAxes.InnerPosition(4)]; %UIAxes y coordinates
    axisXcoords = [app.UIAxes.InnerPosition(1),...
        app.UIAxes.InnerPosition(1) + app.UIAxes.InnerPosition(3)]; %UIAxes x coordinates
    
    %if statement basically asking if you're pointing inside the UIAxes
    %InnerPosition and also asks if there is data in the UIAxes. You're
    %using a picture so that may need to be updated for you
    if PointerLocation(1) > axisXcoords(1) &&...
            PointerLocation(1) < axisXcoords(2) &&...
            PointerLocation(2) > axisYcoords(1) &&...
            PointerLocation(2) < axisYcoords(2) &&...
            ~isempty(app.UIAxes.Children)
                    
        ZoomMag = 10; %zoom magnification

        xCalibrate = (app.UIAxes.XLim(2) - app.UIAxes.XLim(1))/...
            app.UIAxes.InnerPosition(3); %x value per UIAxes inner pixel
        yCalibrate = (app.UIAxes.YLim(2) - app.UIAxes.YLim(1))/...
            app.UIAxes.InnerPosition(4); %y value per UIAxes inner pixel
        
        %find what your x and y value are at your cursor within the UIAxes
        xValue = xCalibrate*(PointerLocation(1)-app.UIAxes.InnerPosition(1));
        yValue = yCalibrate*(PointerLocation(2)-app.UIAxes.InnerPosition(2));
        
        %need to get original data 
        xData = app.UIAxes.Children.XData;
        yData = app.UIAxes.Children.YData;
        
        %plot the pointer location as a black x and plot the original data
        %on UIAxes2
        plot(app.UIAxes2,...
            xValue,yValue,'xk',...
            xData,yData,'-o')
        
        %adjust the x and y limits on UIAxes2
        xlim(app.UIAxes2,...
            [xValue - (app.UIAxes.XLim(2) - app.UIAxes.XLim(1))/ZoomMag,...
            xValue + (app.UIAxes.XLim(2) - app.UIAxes.XLim(1))/ZoomMag])
        ylim(app.UIAxes2,...
            [yValue - (app.UIAxes.YLim(2) - app.UIAxes.YLim(1))/ZoomMag,...
            yValue + (app.UIAxes.YLim(2) - app.UIAxes.YLim(1))/ZoomMag])
    end
end