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Microsoft Active Accessibility

  • Artikel

Microsoft Corporation

August 2001

Summary: This overview describes how Microsoft Active Accessibility can help software developers make their programs more compatible with accessibility aids, and accessibility aid developers can make more reliable and robust aids. (3 printed pages)

  • Introduction
  • What Does Active Accessibility Do?
  • What Are Accessibility Aids?
  • How Does Active Accessibility Help Developers?
  • Do Other Companies Use Active Accessibility?

Introduction

Microsoft Active Accessibility is a developer technology that improves the way programs and the operating system work with accessibility aids. Active Accessibility can help software developers make their programs more compatible with accessibility aids, and accessibility aid developers can make more reliable and robust aids.

As an underlying technology, Active Accessibility is invisible to users. Active Accessibility, used by developers since 1997, may already be in the operating system and programs you use today. For example, Active Accessibility is in Microsoft Office, Microsoft Windows, and Microsoft Internet Explorer.

A wide range of accessibility aids also use Active Accessibility. You can find out whether an aid already includes Active Accessibility by contacting the aid vendor. Contact information for many accessibility aid vendors is available from the Microsoft catalog of accessibility aids.

What Does Active Accessibility Do?

Active Accessibility provides a standard way for accessibility aids to get information about user interface elements, and for programs to expose that information to the aids. For example, Active Accessibility provides these individual pieces of information:

  • Type of object
  • Name of object
  • Location of object
  • Current state of object

And it provides:

  • Notification of changes in user interface via Windows Events, and
  • Navigation (spatial and logical)

This standard helps program developers and aid developers alike ensure their products are compatible.

The standard also gives software developers who use Active Accessibility more flexibility in designing their program user interfaces. Knowing what aids need, software developers can innovate more freely without sacrificing compatibility. On the other hand, aid developers can have confidence that the products they create will work well with programs that use Active Accessibility because it:

  • Provides built-in support in the operating system.
  • Makes available a COM interface and API elements that help replace the unreliable and less portable techniques developers had to use in the past.
  • Provides the framework for programs and operating systems to cooperate with accessibility aids.
  • Provides methods for exposing information about custom controls.
  • Exposes information about most system-provided user interface elements, such as list boxes and buttons.
  • Provides a mechanism for accessibility aids to be notified when the user interface changes.

What Are Accessibility Aids?

Accessibility aids are specialized programs and devices that help people with disabilities use computers more effectively. There are many types of aids. Some examples include:

  • Screen enlargers for people who have low vision
  • Screen readers for people who are blind
  • Voice input utilities for people who provide verbal commands to their computers instead of using the keyboard or mouse

How Does Active Accessibility Help Developers?

Active Accessibility provides a standard way for accessibility aids to get information about user interface elements, and for programs to expose that information to the aids. This standard helps program developers and aid developers alike ensure their products are compatible with each other.

The standard also gives software developers who use Active Accessibility more flexibility in designing their program user interfaces. Knowing what aids need, software developers can innovate more freely without sacrificing compatibility. On the other hand, aid developers can have confidence that the products they create will work well with programs that use Active Accessibility.

In general, Active Accessibility helps because it:

  • Provides dynamic link libraries that are incorporated into the operating system.
  • Makes available a COM interface and API elements that help replace the unreliable and less portable techniques developers had to use in the past.
  • Provides the framework for programs and operating systems to cooperate with accessibility aids.
  • Provides methods for exposing information about custom controls.
  • Exposes information about most system-provided user interface elements, such as list boxes and buttons.
  • Provides a mechanism for accessibility aids to be notified when the screen changes.

Do Other Companies Use Active Accessibility?

Many other companies are now using, or are planning to use, Active Accessibility. Microsoft is actively promoting the benefits of Active Accessibility to the software industry, the accessibility community, and others with the expectation that increasing awareness will encourage other companies to include Active Accessibility in their products. Ultimately, Active Accessibility increases options for people who depend on accessibility aids to use computers.

 

 

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