Access Issues for Selected Development Environments
Some techniques for creating accessible software are specific to the development environment being used. This section provides information and further resources for developers working on the Windows OS and Macintosh OS, and for the Java environment, Macromedia Director and Web developers.
Windows OS
Microsoft provides detailed information on building accessible software for the Windows platform. The Microsoft Accessibility and Disabilities Group has created tools, documents and APIs that offer ways to take advantage of access features in the operating system and provides information on other ways to make software more accessible. The Microsoft Windows Guidelines for Accessible Software Design provide comprehensive information on creating accessible software.
In particular, the Microsoft Active Accessibility API (MSAA) uses programmatic means to help software communicate with assistive technologies. MSAA exposes elements of the screen and their state. It also exposes the focus of the screen. Using MSAA, software developers can use entirely custom graphical interfaces while still making each element known to an assistive technology that has been programmed to read this information and convey it to the user.
Resources
Microsoft Accessibility Home Page
Microsoft Active Accessibility: Introduction
Microsoft Windows Guidelines for Accessible Software Design
Macintosh OS
All Macintosh computers ship with several accessibility features already installed that support users with sensory or physical disabilities. Developers may want to test their products with these features invoked to determine whether their software is operable by users requiring assistive technology. Some of the pre-installed accessibility features include the following:
- text-to-speech technology including the PlainTalk speech synthesizer
- voice recognition technology
- CloseView, a built-in screen magnifier for low-vision users
- StickyKeys, software that allows users to strike keys one at a time in cases where two or three keys would normally be pressed simultaneously, such as Shift+F9
- MouseKeys, software that allows users to control all mouse movements by typing on the numeric keypad
In addition to the built-in accessibility features for the Macintosh, Apple maintains a list of Mac-based assistive technology available from vendors outside of Apple. outSPOKEN is the only screen reader developed for the Macintosh platform. For this reason developers should test their products with outSPOKEN. Users who are blind will not be able to use Web sites and educational software if the product is not compatible with this screen reader.
Apple also has a developer Web site that contains an array of resources including the Macintosh Human Interface Guidelines. This document provides "authoritative information on the theory behind the Macintosh 'look and feel' and the practice of using individual interface components. This book includes many examples of good design and explains why one implementation is superior to another."
Apple Disability Resources
Contains links to information about built-in accessibility features for all Macintosh OSes, including the new Universal Access system preference in OS X. Also see the database of third-party disability products for the Macintosh.
Macintosh Human Interface Guidelines
Accessibility information is sprinkled throughout this document.
Universal Access in Macintosh Human Interface Guidelines
Human Interface Design Principles in the Macintosh Human Interface Guidelines
Key accessibility information is included in this section.
Alva Access Group
Alva Access Group manages the development of the outSPOKEN screen reader and inLARGE, a screen magnifier, for the Macintosh. Programmers should download Alva's time-based demos of their products for testing purposes.
The Java™ Platform
The Java platform is an attractive development environment for creating accessible educational software for several reasons:
- Java is a platform-independent language that allows educational software to be accessed from both Macintosh and Windows.
- Accessibility features are built into Java technology's core structure and are supported by the Swing user interface components, which include an effective keyboard interface.
- The Java accessibility API, a standard extension in the Java 2 platform, eliminates any need for retrofitting to enable Java-based assistive technologies to interact effectively with mainstream applications.
- The Sun access team has also developed the Java Access Bridge, which allows users to run Java applications with their platform-specific assistive technologies, such as Windows screen readers.
The Java accessibility API contains several properties that enable developers to determine how assistive technology reports the presence and status of a particular object. Two of the most crucial properties are an object's accessible name and accessible description. Because the accessibility API is built in to Swing components, many UI elements will have their accessible name set automatically. Other components may need a label associated with the object, using the command setLabelFor().
The accessible description may be a longer piece of text needed to provide better context. Accessible descriptions can be set via Jcomponent.setTooltipText(), which has the advantage of updating the description automatically if the tooltip is changed. If an object's accessible name and accessible description are set manually, labels or tooltips added in future releases will not be automatically updated.
Further information on writing accessible Java applications is available from a number of resources:
Guidelines for Writing Accessible Applications Using 100% Pure Java
Sun Microsystems' Accessibility Program/Developer Information
Java Accessibility Helper
Identifies areas in an application's UI where the accessibility support has been improperly used.
Developing Accessible JFC Applications
Focuses on strategies for passing Java Accessibility Helper tool tests.
Java Accessibility Quick Tips: Ensuring and Verifying Basic Application Accessibility
The Java Tutorial/Accessibility Section
Macromedia Products
Macromedia, Inc., produces popular software for creating, building and managing Web sites and stand-alone applications. Historically, Macromedia products have not been very accessible to authors or users with disabilities. However, the company is working to integrate accessibility features and enhancements into their product line. See the Macromedia accessibility page for complete information.
Macromedia Director
Macromedia Director is a commonly used authoring tool for educational software, but it has significant limitations for accessible design. No comprehensive guidelines are available for creating accessible software in Director. If you are using Director to create content, use the information in the section on disabilities, functional limitations, and accessibility tips, and consult the general guidelines on software accessibility referenced at the beginning of that section.
Applications created with Director are not compatible with assistive technologies, but Director MX includes features that support the development of directly accessible applications via an included text-to-speech Xtra (a programmer's tool that expands the functionality of Director). These new accessibility features allow developers to associate text to be voiced with graphic members of the Director application. This provides additional textual information to help users understand and navigate the application and to create a tab order for keyboard users.
One challenge of directly accessible Director content is that developers must provide additional information about on-screen items in order for them to be useful. For example, a blind user might hear the words associated with an item- words on a button, for example- but not realize that the item itself is actually available unless the developer indicates this by adding informational text to be voiced.
Director does not by default support using the keyboard to interact with on-screen controls. Developers generally create mouse interactions for each object. If an application has a series of buttons displayed, the developer must use the accessibility features of Director MX to add code that permits the use of the Tab key to move the focus from item to item, and to have the Enter key or space bar trigger activation of the button. This keyboard support is not limited to Director MX, but advanced knowledge is required on the part of the developer in order to implement it in previous versions of Director.
In addition, the custom menu bars developers can create in Director look like Macintosh OS menu bars but do not behave in a standard way. They are not compatible with screen readers for Macintosh. All features available in the menus must be made available in some other way, such as with a keyboard shortcut or in an accessible dialog box. It may be also be possible to use the text-to-speech solution within Director MX. Because of these limitations, developers using Director to create educational software must create directly accessible applications. This includes building a full keyboard interface so that students who cannot use a mouse can access the software, and providing full audio output for visually impaired users. Audio can be provided by recording a narrator voicing all text or by using text-to-speech software to voice text strings.
In some cases, a product can be designed to include default features for low-vision users, such as choice of font size or high-contrast colors. A Director Xtra can add text-to-speech to Director applications. See Macromedia Xtras Developer Support for the most up-to-date information on Xtras and on implementing keyboard access. (Note that Macromedia Director MX includes a text-to-speech Xtra which can be accessed via the Library.) Also consult DirectXtras to learn about Xtras related to text-to-speech, including DirectTTS, which provides applications with the ability to talk by transforming text to speech. Electronic Ink also has a text-to-speech Xtra, Yak Xtra, for Director and Authorware.
Video in a Director application can be made accessible by providing closed captions and audio descriptions. If QuickTime movies are embedded within a Director application, the access tracks can be controlled within Director by referencing the tracks by track number. For example, if the main video track is track one, the main audio is track two, the captions are track three, and the audio description is track four, then buttons can be added to the user interface that allow users to turn captions and description on and off. Use the track numbers to send the information about which tracks to display to QuickTime. See Guideline 2 for complete information on preparing captions and audio descriptions for digital multimedia.
Can Studios, a media design company in England, has developed Canvas Learning, a tool for creating and delivering accessible e-learning and assessment, which is based on Macromedia Director. One example is "The Street," an accessible 20-hour course that delivers key communication skills. The course targets high school and college students between the ages of 16 and 25. The Can Studios software is designed to be directly accessible, so that a person with a disability can operate all of the built-in access features of the product without relying on an assistive technology. The software offers a full keyboard interface and audio output for all visual commands and lessons. New titles created in Canvas Learning will also offer an integrated magnification tool. Visit Canvas Learning for more information, including an overview of accessibility features and a demo. You may also view a sample of "The Street."
Another example of a directly accessible Director application is available courtesy of NCAM's CD-ROM Access Project. The prototype accessible version of How the West Was One + Three x Four (based on the original program from Sunburst Communications, Inc.) shows how a full keyboard and audio interface can be created using Director, allowing all students to use a math game that originally was inaccessible. See a description of the accessible prototype for more information.
Macromedia Flash
To help users get the most from a Flash experience, Flash Player 6 has integrated support for Microsoft Active Accessibility (MSAA). MSAA serves as a bridge between Flash Player 6 and assistive technologies such as the JAWS and Window-Eyes screen readers. By default, Flash Player 6 recognizes text symbols and text within movie clips and button symbols. Text elements and buttons in movies created in Flash 4 and 5 are therefore available to screen readers, without modification. This means the majority of Flash content available today will be significantly more accessible when used with Flash Player 6. However, this doesn't guarantee that the content was authored to be accessible.
Authors of Flash content may now also take advantage of accessibility features of Flash MX. Using the new Accessibility panel, authors can specify text equivalents for elements of Flash movies and provide control over how assistive technologies handle these elements. The Accessibility panel allows authors to specify a brief descriptive text equivalent (similar to HTML's alt attribute); authors may also write a longer text equivalent if necessary. MSAA then passes this information to assistive technologies, such as a screen reader.
Two resources for more information about Flash accessibility are:
MacGregor, Chris, et. al. The Flash Usability Guide. Birmingham: friends of ED, 2002.
Thatcher, Jim, et. al. Constructing Accessible Web Sites. Birmingham: glasshaus, 2002.
Macromedia Authorware
Authorware is commonly used by developers of on-line learning content, including Web-based tutorials, tests and simulations. Version 6.5 contains accessibility authoring features unavailable in previous versions. For example, authors can now add screen reader support to presentations as well as text alternates and equivalents for images. Authorware contains a new accessibility Knowledge Object with commands, models and techniques for text-to-speech that helps to create accessible user interfaces. It can also detect the presence of a screen reader, such as JAWS or Window-Eyes, on a user's computer. Blind or visually impaired users may operate Authorware with a screen reader, although some differences will exist between standard and Authorware key mappings.
For authors who wish to integrate accessible video and audio into an Authorware presentation, they should first caption or describe the multimedia using NCAM's Media Access Generator (MAGpie). The accessible multimedia created by MAGpie can then be incorporated into the Authorware presentation. Authors should always provide an interface, such as a series of accessible buttons, for toggling the captions or audio descriptions on and off. See Guideline 2 for complete information on adding captions and audio descriptions to multimedia. For more information, read about Authorware's accessibility features.
W3C Recommendations
Content written in HTML can benefit from the extensive work on accessibility done by the World Wide Web Consortium (W3C), an industry consortium that aims to lead the World Wide Web to its full potential by developing common protocols that promote its evolution and ensure its interoperability. The Web Accessibility Initiative (WAI) at the W3C coordinates with organizations and industry representatives to ensure that the Web is accessible to people with disabilities.
Content written in HTML and other Web technologies should follow the Web Content Accessibility Guidelines. Production of version 2.0 of the guidelines is under way at the time of this writing; see the WCAG Web site for updates and more information. Software that allows users to author their own Web content should follow the Authoring Tools Accessibility Guidelines.
Resources are also available for those authoring content and software in the following formats:
XML (Extensible Markup Language)
WAI XML Accessibility Guidelines
SMIL (Synchronized Multimedia Integration Language)
Accessibility Features of SMIL
CSS (Cascading Style Sheets)
Accessibility Features of CSS
SVG (Scalable Vector Graphics)
Accessibility Features of SVG
Creating content according to the Web Content Accessibility Guidelines and allowing users to view it in the browser most accessible to them is the easiest method of creating accessible software. Software that provides a proprietary interface to HTML content should follow the WAI User Agent Accessibility Guidelines. However, for maximum accessibility, users should be able to choose their own Web browser to view material the software provides. Students with disabilities can then take advantage of assistive technologies of which software developers may not be aware. Locking users into a specific browser can reduce the accessibility of even well-designed Web content. Assistive technologies for use with HTML content may include a talking MathML browser or plug-in, or access features designed into mainstream browsers like Internet Explorer and Opera. Additionally, there are specially designed talking Web browsers on the market, such as IBM Home Page Reader.