Setting Figure Size in MATLAB App Designer

MATLAB App Designer provides a powerful interface for creating professional-grade graphical user interfaces (GUIs) for MATLAB programs. One of the key aspects of GUI design is controlling the size of figures, or windows, in which the GUI elements are displayed. The figure size is essential for ensuring that all elements are visible and interactable, and it contributes significantly to the overall user experience.

Understanding MATLAB Figure Properties

In MATLAB, figures are windows that contain axes, controls, and other graphical elements. The size and position of a figure are determined by its properties, particularly the Position property. The Position property is a four-element vector that specifies the size and location of the figure on the screen in the format [left bottom width height].

• Left and Bottom: These specify the distance from the lower-left corner of the screen to the lower-left corner of the figure.
• Width and Height: These specify the size of the figure in pixels.

For example, setting the Position property to [100 100 800 600] creates a figure that is 800 pixels wide, 600 pixels tall, and positioned 100 pixels from the left edge and 100 pixels from the bottom edge of the screen.

Setting Figure Size in App Designer

When designing an app in MATLAB App Designer, controlling the size of the main figure (app window) is crucial for creating a well-designed interface. Here's how to set the figure size in MATLAB App Designer:

1. Accessing the Figure Properties: The figure in App Designer is represented by the UIFigure object. You can access its properties in the Design View by clicking on the background of the app or in the Code View by referencing app.UIFigure.

2. Setting the Position: To set the figure size, modify the Position property of app.UIFigure. For example, in the StartupFcn callback, you can add the following code:

   matlab
   app.UIFigure.Position = [100 100 1200 800];
   

   This code sets the figure size to 1200x800 pixels and positions it 100 pixels from the left and bottom edges of the screen.

3. Dynamic Resizing: If you want the figure to resize dynamically based on screen resolution or user preferences, you can programmatically adjust the Position property in response to events or conditions. For instance, you could use the SizeChangedFcn callback to resize UI elements when the figure size changes.

   matlab
   function updateUIComponents(app)
       % Adjust component positions and sizes based on app.UIFigure size
       app.UIAxes.Position = [20 60 app.UIFigure.Position(3)-40 app.UIFigure.Position(4)-80];
   end
   

4. Using AutoResize: MATLAB App Designer also provides an AutoResizeChildren property for the UIFigure, which, when set to on, automatically resizes and repositions child components based on the figure size. However, for more control, it is often better to manage resizing programmatically.

Best Practices for Setting Figure Size

• Consistency: Maintain a consistent figure size across different windows of your app to ensure a cohesive user experience.
• Resolution Considerations: Consider the screen resolution of your target audience. Set the figure size appropriately to ensure all elements are visible without requiring scrolling or resizing.
• User Preferences: Allow users to adjust the figure size according to their preferences. You can save and load these preferences using MATLAB’s getpref and setpref functions.
• Responsive Design: Implement responsive design principles where possible, adjusting the layout and size of UI components based on the figure size to provide an optimal experience on different screen sizes.

Example: Creating a Responsive App Layout

Here is an example of how you might create a responsive layout in MATLAB App Designer by setting and adjusting the figure size:

matlab
classdef MyApp < matlab.apps.AppBase

    % Properties
    properties (Access = public)
        UIFigure  matlab.ui.Figure
        UIAxes    matlab.ui.control.UIAxes
        UITable   matlab.ui.control.Table
    end

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

        % Code that executes after component creation
        function startupFcn(app)
            % Set initial figure size
            app.UIFigure.Position = [100 100 800 600];
            app.updateLayout();
        end

        % Code to update layout based on figure size
        function updateLayout(app)
            % Calculate positions based on figure size
            figWidth = app.UIFigure.Position(3);
            figHeight = app.UIFigure.Position(4);

            % Adjust positions of UI components
            app.UIAxes.Position = [20 figHeight-220 figWidth-40 200];
            app.UITable.Position = [20 20 figWidth-40 figHeight-260];
        end
    end
end

In this example, the updateLayout method adjusts the positions of UIAxes and UITable based on the size of the figure. This ensures that the UI components remain appropriately sized and positioned as the figure size changes.

Common Pitfalls and Troubleshooting

• Fixed Size Components: Avoid setting fixed sizes for UI components unless absolutely necessary. Instead, rely on relative positioning and dynamic resizing to accommodate different screen sizes.
• Overlapping Components: Ensure that your components do not overlap when the figure is resized. This can be managed by setting appropriate margins and using the AutoResizeChildren property judiciously.
• Performance Considerations: Be mindful of the performance impact of dynamic resizing, especially in complex apps with many UI components. Optimize your layout logic to minimize lag and ensure smooth resizing.

Conclusion

Setting and managing figure size in MATLAB App Designer is a crucial part of creating a user-friendly and professional GUI. By understanding the properties of figures, using best practices for layout management, and implementing responsive design techniques, you can create applications that look great and function well across different devices and screen resolutions.

Summary of Key Points:

• Figure Size and Position: Controlled by the Position property.
• Setting Size in App Designer: Modify the Position property of app.UIFigure.
• Dynamic Resizing: Use callbacks like SizeChangedFcn to adjust layout dynamically.
• Best Practices: Consistency, resolution considerations, user preferences, and responsive design.
• Example: Demonstrates a responsive layout in MATLAB App Designer.

By following these guidelines, you can ensure that your MATLAB App Designer projects are well-structured, visually appealing, and easy to use. Whether you're creating simple tools or complex applications, proper figure sizing and layout management are fundamental to success.