Saving Screenshots in MATLAB App Designer

MATLAB App Designer is a powerful tool for creating interactive applications and GUIs (Graphical User Interfaces) in MATLAB. One common requirement for users developing apps is to save screenshots of their app interfaces. This article provides a comprehensive guide on how to capture and save screenshots of MATLAB App Designer applications. We will cover various methods, including built-in functions, custom code, and third-party tools.

Introduction Capturing screenshots is a useful feature for documentation, debugging, or sharing your application’s appearance with others. While MATLAB App Designer does not have a direct "Save Screenshot" button, you can accomplish this task using MATLAB's capabilities and custom scripting.

Method 1: Using exportgraphics Function MATLAB R2020a introduced the exportgraphics function, which allows users to export graphics objects to image files. This function can be used to save screenshots of your app's figures or panels.

Example Code:

matlab
% Create a UI figure
fig = uifigure;

% Add a button
btn = uibutton(fig, 'push', 'Text', 'Click me');

% Save screenshot
exportgraphics(fig, 'screenshot.png', 'Resolution', 300);

Explanation:

• uifigure creates a new figure window for the app.
• uibutton adds a button to the figure.
• exportgraphics captures the figure and saves it as 'screenshot.png' with a resolution of 300 DPI.

Method 2: Using getframe and imwrite If you need more control over the screenshot capture, you can use the getframe function to capture the figure content and imwrite to save it as an image file.

Example Code:

matlab
% Create a UI figure
fig = uifigure;

% Add a button
btn = uibutton(fig, 'push', 'Text', 'Click me');

% Capture the frame
frame = getframe(fig);

% Convert to image and save
img = frame2im(frame);
imwrite(img, 'screenshot.png');

Explanation:

• getframe captures the current frame of the figure.
• frame2im converts the frame to an image array.
• imwrite saves the image array as 'screenshot.png'.

Method 3: Using print Function The print function in MATLAB is another way to capture and save figures, including those created with App Designer.

Example Code:

matlab
% Create a UI figure
fig = uifigure;

% Add a button
btn = uibutton(fig, 'push', 'Text', 'Click me');

% Save screenshot
print(fig, 'screenshot', '-dpng', '-r300');

Explanation:

• print saves the figure as 'screenshot.png' with a resolution of 300 DPI.

Method 4: Using Third-Party Tools For users who prefer a more visual approach, third-party screenshot tools can be used. Tools like Snipping Tool (Windows) or Screenshot (macOS) allow users to capture any part of the screen, including the MATLAB App Designer interface.

Steps:

1. Open your MATLAB App Designer application.
2. Launch a third-party screenshot tool.
3. Select the region of the screen you want to capture.
4. Save the captured image.

Best Practices for Capturing Screenshots

• Resolution: Ensure high resolution for clear and detailed screenshots. Use 300 DPI for printing quality.
• Region Selection: Capture only the relevant parts of the app to keep the screenshot focused.
• File Format: PNG is preferred for screenshots due to its lossless compression.

Troubleshooting Common Issues

• Blank Screenshots: Ensure that the figure or component is fully rendered before capturing.
• Low-Quality Images: Increase the DPI setting or use high-resolution display settings.

Conclusion Capturing and saving screenshots in MATLAB App Designer can be achieved through various methods, including built-in functions and third-party tools. By selecting the appropriate method for your needs, you can effectively document and share your MATLAB applications.

Table of Methods

Method	Function Used	Code Example	Output Format
exportgraphics	exportgraphics	Yes	PNG
getframe + imwrite	getframe, imwrite	Yes	PNG
print	print	Yes	PNG
Third-Party Tools	N/A	No	Various