- Platform identity: Each desktop operating system (Windows, macOS, Linux) has distinct design guidelines. Windows uses Microsoft Fluent Design with acrylic effects, macOS follows Apple Human Interface Guidelines with translucent materials and unified titlebars, while Linux desktops vary by distribution but often mimic one of these. Respecting these conventions ensures users feel at home with your app.
- Window chrome: The window frame (title bar, close/minimize/maximize buttons) is managed by the OS. Custom chrome can break expected behaviors like snap, shake, or mission control. Always consider whether custom titlebars add value outweighing the loss of native gestures.
- Standard controls: Users expect consistent interaction models for menus, toolbars, checkboxes, radio buttons, and sliders. Using platform-native controls (NSButton on macOS, Button on WinUI) ensures keyboard navigation, accessibility, and high-DPI rendering work automatically.
- Menu bar: macOS places the app menu at the top of the screen, while Windows and Linux embed it in each window. Designing for both requires adaptive layouts that shift menu placement based on the OS detected at runtime.
- Drag and drop: Desktop apps commonly support drag-and-drop from file managers. This requires handling file types, validating data, and providing visual feedback like drag shadows and drop zones. The behavior should match OS-level drag patterns.
- Right-click context menus: Context menus provide quick access to actions relevant to the selected item. They should appear on right-click (or control-click on macOS single-button mice) and include standard entries like Cut, Copy, Paste, Delete, and Properties where applicable.
- System integrations: Desktop apps can register for file associations, URL protocols, and custom notification handlers. A well-integrated app opens the correct file type, responds to deep links, and sends native notifications that respect Focus Assist or Do Not Disturb settings.
- Accessibility out of the box: Native controls inherently support screen readers, keyboard navigation, and High Contrast mode. Custom controls require extra effort to implement ARIA-like roles and expose the correct accessibility tree to platform APIs like UI Automation on Windows or VoiceOver on macOS.
Principle: Platform Fidelity
Definition: A desktop app should feel native to its operating system by adopting visual and behavioral conventions of that platform. This includes using standard window chrome, controls, menus, and keyboard shortcuts (e.g., Ctrl+C on Windows, Cmd+C on macOS) without inventing new interactions that confuse users.
Application: When designing a document editor for both Windows and macOS, use the OS-specific font rendering and spacing. On Windows, use Segoe UI for text, and on macOS, use San Francisco. Implement a menu bar that on macOS sits on the top screen bar, and on Windows inside the window. Users switching platforms will find the app familiar and predictable.
Type Family: System fonts (San Francisco for macOS, Segoe UI for Windows, Noto Sans for Linux)
Hierarchy:
- H1: 20px Bold on Windows, 20px Semibold on macOS
- H2: 16px Bold on Windows, 16px Semibold on macOS
- Body: 14px Regular on Windows, 13px Regular on macOS
- Caption: 12px Regular on Windows, 11px Regular on macOS
Pairing: Use the system font for all UI text. For content areas, a neutral reading font like Open Sans (Windows) or Helvetica (macOS) can be used, but maintain platform font for chrome elements.
- Desktop platforms have unique design guidelines; follow them for native feel.
- Custom window chrome must be weighed against loss of standard OS gestures.
- Native controls provide built-in accessibility and keyboard navigation.
- Menu bar placement differs between macOS (top screen bar) and Windows/Linux (window-specific).
- Drag-and-drop and context menus should mirror OS patterns.
- System integrations like file associations and notifications improve user experience.