MATLAB: Removing any previously draw roi on an image

deletefindallMATLABroi.ellipse

Hello. I have an image in a UIAxes component (app designer) and have the code below. Everytime I run the code (via pushButton callback), I want tod elete any previous roi ellipses and create a new one, hence I try and delete any previous ones. The way I've done doesn't do anything

            [sx,sy]=size(app.imgArray{1})
            ax=app.UIAxes3;
            g=get(ax,'children')
            findall(g, 'type', 'Ellipse');
            t = findall(g, 'type', 'Ellipse'); delete(t);
            h = images.roi.Ellipse(app.UIAxes3,'Center',[round(sy/2) round(sx/2)],'Semiaxes',[round(sx/2) round(sx/2)],'Color','r','StripeColor','b','LineWidth',1);

Have also tried (but didn't work)

            findall(g, 'type', 'line');
            t = findall(g, 'type', 'line'); delete(t);

Best Answer

findobj(ax,'Type','images.roi.Ellipse')

Related Solutions

MATLAB: How to retrieve intensities of a ROI in App Designer

See attached demos for masking.

MATLAB: Accessing an ROI move listener in another function so to delete it

Assuming you don't want to delete the ellipse, you could instead delete the listener within your button's callback function. You can pass the listener to that function in a number of ways, one of which is to save the listener within (or as) a property of your app. Another possibility is to directly pass the listener to your button's callback property. I hope the following helps illustrate this, even though it is simply a script and not tied to an object like in appdesigner:

f = uifigure;
ax = axes(f, 'Position', [0.1, 0.6, 0.8, 0.4]);
b = uibutton(f,...
    'Position', [0.1*f.Position(3), 0.1*f.Position(4), 0.8*f.Position(3), 0.4*f.Position(4)],...
    'ButtonPushedFcn', @buttonpress);
% Draw ROI
h = images.roi.Ellipse(ax, 'Center', [0.5 0.5],...
    'Semiaxes', [0.3 0.3]);
% Listen for mouse movement of the ROI
l = addlistener(h, 'MovingROI', @allevents);
% Update button's callback, passing in the listener l
b.ButtonPushedFcn = {b.ButtonPushedFcn, l};
function allevents(~, evt)
    evname = evt.EventName;
    if strcmp(evname, 'MovingROI')
        disp(['ROI moving Current Center: ' mat2str(evt.CurrentCenter)]);
        disp(['ROI moving Current SemiAxes: ' mat2str(evt.CurrentSemiAxes)]);
    end
end
function buttonpress(src, ~, l)
    if nargin > 2 % if nargin > 3 in appdesigner, I believe
        delete(l)
        % src.ButtonPushedFcn = @buttonpress;
    end
end

Best Answer

Related Solutions

MATLAB: How to retrieve intensities of a ROI in App Designer

MATLAB: Accessing an ROI move listener in another function so to delete it

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