uno-test-resize-app-window

Resize App Window on macOS for Visual Testing

Resize a running Uno Platform desktop app window programmatically using the macOS Accessibility API. Useful for verifying responsive layout behavior at specific widths without manual interaction.

Prerequisites

• macOS with Accessibility API access granted to the terminal/IDE
• A running Uno Platform desktop app (use uno_app_start / uno_app_get_runtime_info first)

Usage

Run resize-window.sh with three arguments:

resize-window.sh APP_NAME WIDTH HEIGHT

• APP_NAME — the app's process name (from uno_app_get_runtime_info → Process Name)
• WIDTH — target window width in pixels
• HEIGHT — target window height in pixels

Common Test Widths

Width	Columns (typical)	Use case
500	1	Mobile / narrow
750	2	Tablet / medium
1024	3	Desktop / wide
1280	3-4	Large desktop

Workflow

1. Start the app with uno_app_start
2. Confirm running with uno_app_get_runtime_info (note Process Name)
3. Take initial screenshot with uno_app_get_screenshot
4. Run resize-window.sh "AppName" 500 800
5. Take screenshot and verify layout reflow
6. Repeat at additional widths as needed
7. Restore original size when done

Troubleshooting

• "App not found": Verify the process name matches exactly (case-sensitive). Check with uno_app_get_runtime_info.
• "Resize failed: -25211": Accessibility access not granted. The user must grant access in System Settings > Privacy & Security > Accessibility for the terminal app.
• Xcode objc warnings in stderr: Harmless; ignore. The resize still succeeds.

Notes

• This technique uses the macOS Accessibility API (AXUIElement), not AppleScript. AppleScript System Events requires separate assistive access and often fails for non-scriptable apps.
• The script targets the first window of the process. If the app has multiple windows, only the first is resized.
• Window position can also be set by replacing kAXSizeAttribute with kAXPositionAttribute and using CGPoint instead of CGSize.