Create a selectable grid in a MATLAB app

I am trying to create a MATLB app with APPDesigner. I have added an axis element that has to contain a series of subplots (16x16). I have been able to create the subplots and plot them in the app. However, I wanted to create a grid that separates the subplots, and lets the user select a specific square from the grid to then display their selection in the app. This is what I currently have:

 k = 1;
            axes_handle = app.SpectralPlotAxes;
            figure_spectra = fiu¡gure('Visible', 'off'); % Create a new figure (not visible)
            hold on;
            figureWidth = 800; % Adjust the figure width as desired
            figureHeight = figureWidth; % Set the figure height equal to the width to make it square
            set(figure_spectra, 'Units', 'pixels');
            set(figure_spectra, 'Position', [100, 100, figureWidth, figureHeight]);
            for i = 1:length(FID_data(1,:,1))
                for j = 1:length(FID_data(1,1,:))
                     current_data = FID_data(:, j, i);
                     subaxis(16,16,k, 'Spacing', 0, 'Padding', 0, 'Margin', 0,'SpacingHoriz', 0);
                     plot(current_data)
                     ylim([0 a])
                     k = k+1;
                     set(gca, 'XTickLabel', []);
                     set(gca, 'YTickLabel', []);
                     set(gca, 'Color','w', 'XColor','b', 'YColor','b')
             
                end
            end
            
            frame = getframe(gcf);
            spectral_data = frame.cdata;

            imshow(imageData,'Parent',axes_handle);
            numRows = length(FID_data(1,:,1));
            numCols = length(FID_data(1,:,1));
            
            % Determine the size of each grid cell
            [height, width, ~] = size(spectral_data);
            cellHeight = height / numRows;
            cellWidth = width / numCols;

            % Prompt the user to select a grid section
            [x, y] = ginput(1);
            
            % Calculate the selected grid indices
            selectedRow = ceil(y / cellHeight);
            selectedCol = ceil(x / cellWidth);
            
            % Display the selected grid indices
            app.Label.Text = ['X: ', num2str(selectedRow), ', Y: ', num2str(selectedCol)]
            

However, when I run this and load my data, instead of creating the grid over the figure I display, the app opens a new figure of the subplots outside the app and does not let me select anything at all. Could anyone help or guide me to solve this problem?

Thank you

[Mario Malic]

Hey,

try using the CurrentAxes or CurrentObject property from the uifigure object to get the handle to the selected subplot that you can use to display.

https://uk.mathworks.com/help/matlab/ref/matlab.ui.figureappd-properties.html#mw_9947f5f7-275a-4f03-9d2a-88300fecc0b6

Answer 1

[Divyanshu]

Hi Marina,

Here are few points to consider for better understanding of the sample app:

• I have created a sample app which has four subplots.
• These subplots I have created using ‘tiledlayout’ function.
• Initially during the start-up of the app, all the suplots are plotted and corresponding axes to each subplot and the plot itself are hidden.
• Now the user can specify the subplot number in the edit field, based on the choice corresponding subplot is made visible.

Here is the code-view of the app with example of two subplots, which can be extended further based on use-case:

methods (Access = private)
    % Code that executes after component creation
    function createPlot(app)
        fig = uifigure;
        p = uipanel(fig);
        t = tiledlayout(p, 2, 2);
        x = [1:5];
        y = [1,4,6,9,11];
        app.ax1 = nexttile(t);
        app.p1 = plot(app.ax1,x,y);
        app.ax2 = nexttile(t);
        app.p2 = plot(app.ax2,2*x,y);
        set(app.ax1,'visible','off');
        set(app.p1,'visible','off');
        set(app.ax2,'visible','off');
        set(app.p2,'visible','off');
        
    end

    % Button pushed function: SelectButton
    function DisplayTile(app, event)
        app.SPN = app.SubPlotEditField.Value;
        if(app.SPN == 1)
            set(app.ax1,'visible','on');
            set(app.p1,'visible','on');
            set(app.ax2,'visible','off');
            set(app.p2,'visible','off');
        elseif(app.SPN == 2)
            set(app.ax2,'visible','on');
            set(app.p2,'visible','on');
            set(app.ax1,'visible','off');
            set(app.p1,'visible','off');
        end
    end
end

Please refer the following documentation for further details on ‘tiledlayout’ function:

Create tiled chart layout - MATLAB tiledlayout (mathworks.com)