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Windows Considerations

If you are a Windows developer porting your application to Mac OS X, be prepared to make some changes to your application as part of your port. Applications in Mac OS X have an appearance and behavior that are different from Windows applications in many respects. Unless you keep these differences in mind during the development cycle, your application may look out of place in Mac OS X.

The following list provides some guidelines related to the more noticeable differences between Mac OS X and Windows applications. This list is not exhaustive but is a good starting point for developers new to Mac OS X. For detailed information on how your application should look and behave in Mac OS X, see Apple Human Interface Guidelines. For general porting information, see Porting to Mac OS X from Windows Win32 API.

• Avoid custom controls. Avoid creating custom controls if Mac OS X already provides equivalent controls for your needs. Custom controls are appropriate only in situations where the control is unique to your needs and not provided by the system. Replacing standard controls can make your interface look out of place and might confuse users.

• Use a single menu bar. The Mac OS X menu bar is always at the top of the screen and always contains the commands for the currently active application. You should also pay attention to the layout and placement of menu bar commands, especially commonly used commands such as New, Open, Quit, Copy, Minimize, and Help.

• Pay attention to keyboard shortcuts. Mac OS X users are accustomed to specific keyboard shortcuts and use them frequently. Do not simply migrate the shortcuts from your Windows application to your Mac OS X application. Also remember that Mac OS X uses the Command key not the Control key as the main keyboard modifier.

• Do not use MDI. The Multiple Document Interface (MDI) convention used in Microsoft Windows directly contradicts Mac OS X design guidelines. Windows in Mac OS X are document-centric and not application-centric. Furthermore, the size of a document window is constrained only by the user’s desktop size.

• Use Aqua. Aqua gives Mac OS X applications the distinctive appearance and behavior that users expect from the platform. Using nonstandard layouts, conventions, or user interface elements can make your application seem unpolished and unprofessional.

• Design high-quality icons and images. Mac OS X icons are often displayed in sizes varying from 16x16 to 512x512 pixels. These icons are usually created professionally, with millions of colors and photo-realistic qualities. Your application icons should be vibrant and inviting and should immediately convey your application’s purpose.

• Design clear and consistent dialogs. Use the standard Open, Save, printing, Colors, and Font dialogs in your applications. Make sure alert dialogs follow a consistent format, indicating what happened, why it happened, and what to do about it.

• Consider toolbars carefully. Having a large number of buttons, especially in an unmovable toolbar, contributes to visual clutter and should be avoided. When designing toolbars, include icons only for menu commands that are not easily discoverable or that may require multiple clicks to be reached.

• Use an appropriate layout for your windows. The Windows user interface relies on a left-biased, more crowded layout, whereas Aqua relies on a center-biased, spacious layout. Follow the Aqua guidelines to create an appealing and uncluttered interface that focuses on the task at hand.

• Avoid application setup steps. Whenever possible, Mac OS X applications should be delivered as drag-and-drop packages. If you need to install files in multiple locations, use an installation package to provide a consistent installation experience for the user. If your application requires complex setup procedures in order to run, use a standard Mac OS X assistant. For more information, see “Bundles and Packages.”

• Use filename extensions. Mac OS X fully supports and uses filename extensions. For more information about filename extensions, see File System Overview.

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