How to Select GUI axes?

Hello,

I am trying to create a GUI where I load an image and then select points on the image using ginput. However, when I run the callback that contains the ginput line it opens a new window to select points in. In the ginput documentationm it says that I need to set the current axes to the plot that I want to select points in. How do I do this (see line 26)?

Thanks

classdef CameraCalGUI_v1 < matlab.apps.AppBase

    % Properties that correspond to app components
    properties (Access = public)
        UIFigure            matlab.ui.Figure
        UIAxes              matlab.ui.control.UIAxes
        LoadCalImageButton  matlab.ui.control.Button
        UITable             matlab.ui.control.Table
        SelectPointsButton  matlab.ui.control.Button
    end

    % Callbacks that handle component events
    methods (Access = private)

        % Button pushed function: LoadCalImageButton
        function LoadCalImageButtonPushed(app, event)
            path = '';
            [filename, filepath] = uigetfile([path '*.tif']);
            imag = imread([filepath '\' filename]);
            imshow(imag(:,:,1:3),'Parent',app.UIAxes);
        end

        % Button pushed function: SelectPointsButton
        function SelectPointsButtonPushed(app, event)
           set(app.UIFigure,'currentaxes')
            [xi, yi, ~] = ginput(1);
            app.UITable.Data = [app.UITable.Data; xi, yi];
        end
    end

    % Component initialization
    methods (Access = private)

        % Create UIFigure and components
        function createComponents(app)

            % Create UIFigure and hide until all components are created
            app.UIFigure = uifigure('Visible', 'off');
            app.UIFigure.Position = [100 100 640 480];
            app.UIFigure.Name = 'UI Figure';

            % Create LoadCalImageButton
            app.LoadCalImageButton = uibutton(app.UIFigure, 'push');
            app.LoadCalImageButton.ButtonPushedFcn = createCallbackFcn(app, @LoadCalImageButtonPushed, true);
            app.LoadCalImageButton.Position = [70 410 100 22];
            app.LoadCalImageButton.Text = 'Load Cal Image';

            % Create UIAxes
            app.UIAxes = uiaxes(app.UIFigure);
            title(app.UIAxes, 'Calibration Image')
            xlabel(app.UIAxes, 'X')
            ylabel(app.UIAxes, 'Y')
            app.UIAxes.Position = [217 97 396 344];

            % Create UITable
            app.UITable = uitable(app.UIFigure);
            app.UITable.ColumnName = {'X'; 'Y'};
            app.UITable.RowName = {};
            app.UITable.Position = [33 131 174 204];

            % Create SelectPointsButton
            app.SelectPointsButton = uibutton(app.UIFigure, 'push');
            app.SelectPointsButton.ButtonPushedFcn = createCallbackFcn(app, @SelectPointsButtonPushed, true);
            app.SelectPointsButton.Position = [70 365 100 22];
            app.SelectPointsButton.Text = 'Select Points';

            % Show the figure after all components are created
            app.UIFigure.Visible = 'on';
        end
    end

    % App creation and deletion
    methods (Access = public)

        % Construct app
        function app = CameraCalGUI_v1

            % Create UIFigure and components
            createComponents(app)

            % Register the app with App Designer
            registerApp(app, app.UIFigure)

            if nargout == 0
                clear app
            end
        end

        % Code that executes before app deletion
        function delete(app)

            % Delete UIFigure when app is deleted
            delete(app.UIFigure)
        end
    end
end

Answer 1

[Walter Roberson]

ginput() is only for traditional figures. It always uses gcf() but gcf() never finds uifigures.

See https://www.mathworks.com/matlabcentral/answers/392617-how-can-i-use-ginput-in-app-designer

[Christopher Saltonstall]

Is there another function that I can use to select points on a figure in a GUI?

[Walter Roberson]

Not that I know of, but there might be something that could be adapted in the File Exchange.

For a single point, since you are not expecting to draw the points as you go, then use axes CurrentPoint property as described by one of the answers linked to above.

Perhaps use one of the roi functions such as https://www.mathworks.com/help/images/ref/images.roi.crosshair.html