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Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support. Accessibility (Design basics)
In this articleNote This design guide was created for Windows 7 and has not been updated for newer versions of Windows. Much of the guidance still applies in principle, but the presentation and examples do not reflect our current design guidance. Designing software for accessibility means ensuring that programs and functionality are easily available to the widest range of users, including those who have disabilities and impairments. The number of users that accessibility features can help may surprise you; for example, in the United States, surveys have shown that more than half of all computer users experience difficulties or impairments related to accessibility, and are likely to benefit from the use of accessible technology. Moreover, approaching software design with the flexibility and inclusiveness that are the hallmarks of accessibility often results in overall improved usability and customer satisfaction. The Ease of Access Center, available from Control Panel, provides a central location where users can choose and customize the accessibility features they want. Note: Guidelines related to keyboard, mouse, color, and sound are presented in separate articles. Design conceptsMany physical, perceptual, and cognitive factors come into play when users interact with computer hardware and software. Before considering ways to make your program's features more accessible, it helps to learn about what kinds of disabilities and impairments exist, and some of the assistive technologies these users may be working with as they interact with computers. Types of impairmentsThe following table describes common user disabilities and impairments, and lists a few of the most important solutions used to make computers more accessible.
For more guidelines about helping users with these impairments, see Addressing particular impairments later in this article. Types of assistive technologies and accessibility featuresScreen readers A screen reader enables users with visual disabilities or impairments to navigate a UI by transforming visuals to audio. Thus, UI text, controls, menus, toolbars, graphics, and other screen elements are spoken by the computerized voice of the screen reader. To create a program optimized for screen reader assistive technology, you must plan for how the screen reader will identify each UI element. Each UI element that the user can interact with must be keyboard accessible, as well as be exposed through an accessibility application programming interface (API). We recommend using UI Automation, the new accessibility framework for all versions of Microsoft Windows that support Windows Presentation Foundation (WPF). UI Automation provides programmatic access to most elements on the desktop, enabling assistive technology products such as screen readers to provide information about the UI to users and to manipulate the UI by means other than standard input (for example, by speaking rather than or in addition to manipulating the mouse or keyboard). For more information, see the UI Automation Overview. Be aware that although screen readers are a very important assistive technology, there are others as well. For more information about the range of technologies available, see Types of Assistive Technology Products. Speech recognition Speech recognition is an accessibility feature in Windows that allows users to interact with their computers by voice, reducing the need for motor interaction with the mouse or keyboard. Users can dictate documents and e-mail, use voice commands to start and switch between programs, control the operating system, and even fill out forms on the Web. Magnifier Magnification helps users with low vision by enlarging items on screen anywhere from 2 to 16 times the original. Users can set this feature to track the mouse (to see an enlarged version of what the mouse is pointing to), the keyboard (to see the area where the pointer moves when tabbing), or text editing (to see what they are typing). Visual settings and color schemes In addition to making things on the screen larger, users with visual impairment may benefit from system settings such as high-contrast mode or the ability to customize background and foreground color schemes. Narrator Narrator is a scaled-down screen reader in Windows that allows users to hear on-screen text and UI elements read aloud, even including some events (including error messages) that happen spontaneously. The user can hear the Narrator menus without leaving the active window. Users can customize the extent to which Microsoft Narrator is used. On-screen keyboard For users who have difficulty with physical keyboards, and need to use an alternative input device such as a switch, on-screen keyboards are a necessity. Users can select keys using the mouse or another pointing device, a small group of keys, or just one key, depending on how you set up On-Screen Keyboard. Mouse keys With Mouse Keys enabled, users who prefer the keyboard can use the arrow keys on the numeric keypad to move the mouse pointer. For a complete list of accessibility features, see Accessibility in Windows Vista on the Microsoft Web site. Keyboard-based navigationThe Tab key, arrow keys, space bar, and Enter key are important for keyboard-based navigation. Pressing Tab cycles input focus through the different control groups, and pressing the arrow keys moves within a control or among controls within a group. Pressing space bar is the same as clicking the control with input focus, whereas pressing Enter is the same as clicking the default command button or command link, regardless of input focus. In this example, users can press Tab until the desired option has input focus, then press Enter to open the object. Access keysAccess keys allow users to choose options and initiate commands directly without having to navigate to the control first. Access keys are indicated by underlining one of the characters in each control's label. Users then activate the option or command by pressing the Alt key along with the underlined character. Access keys aren't case sensitive. In this example, pressing Alt+O activates the Open command. Choosing logical access keys for controls usually poses no difficulty; the more controls there are on a window, however, the greater the possibility you will run out of access key choices. In this case, assign access keys to control groups rather than each individual one. In this example, access keys are assigned to control groups, rather than individual controls. Access keys are often confused with shortcut keys, but shortcut keys are assigned differently from access keys and have different goals. For example, shortcut keys use Ctrl and Function key sequences and are intended primarily as a shortcut for advanced users instead of for accessibility. For more information, see Keyboard. Designing for accessibility: three fundamental practicesAccessible programs help all users in some way because the objectives of accessibility and usability overlap. For example, features designed to make advanced users as efficient as possible also benefit users who prefer using the keyboard because of dexterity impairment. Three fundamental practices will help you with accessible design: allow for a degree of flexibility in your UI, let respect for user needs and preferences play a major role in design decisions, and provide programmatic access to your UI. Providing flexible UI Accessible design is, at least in part, about giving users choices. Not a frustrating, dizzying array of choices, but a limited number of choices that smartly anticipates user needs. "Don't like navigating by way of the mouse? Here, you can do the very same things using only the keyboard. Don't like physical keyboards? Here's a virtual one you can use on-screen." For example, provide flexibility by:
Multimodal interfaces and flexible navigation essentially offer the user the architecture of information redundancy. Redundancy sometimes has negative connotations; in user interface text, for example, we advise removing redundancy to streamline the reading experience. But in the context of accessibility, redundancy connotes positive, fail-safe mechanisms and experiences. Respecting your users Respect as a general, guiding principle is vital for designing accessible programs. Even as an intellectual exercise, imagine what it must be like to encounter your program as a user who is disabled. Take the time to test UI screens in high contrast mode and at various resolutions, to ensure the experience is a good one for users with visual impairments. Test keyboard accessibility by selecting the Underline keyboard shortcuts and access keys check box in the Ease of Access Center Control Panel item (so that access keys are always visible). You can even go beyond rigorous testing by hiring developers and designers who have a natural aptitude for empathizing with others to begin with. You should also demonstrate respect by:
In software products, respect for users may manifest itself in usability and market research, in efficacious support services and documentation, and of course in design decisions. For example, thinking again in terms of design for advanced users: are you putting that cutting-edge new feature in because you want it, or because you know that your advanced users have been asking for it? The latter case indicates that your design decision-making process is well-informed by the value of respect. Providing programmatic access Providing programmatic access to the UI is essential so that assistive technologies (such as screen readers, alternative input devices, and speech recognition programs) interpret the screen correctly for their users. By creating a "map" of each UI screen in your program, you make it available to users of assistive technologies. Do this well by:
If you do only four things...
GuidelinesGeneral
Addressing particular impairmentsVisual
Hearing
Dexterity
Cognitive
Seizure
Speech or language
Incorrect: Is three the next digit? Click OK to begin. Correct: Is the next digit three? To begin, click OK. Access keys
Menu access keys
Dialog box access keys
For more guidelines and examples, see Keyboard. Text
Documentation
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