The GetCaretBlinkTime function provides access to the current cursor blink rate setting. For more information about this function, see the documentation included in the Win32 SDK.
There are many types of disabilities, but they are often grouped into several broad categories. These include visual, hearing, physical movement, speech or language impairments, and cognitive and seizure disorders.
Visual disabilities range from slightly reduced visual acuity to total blindness. Those with reduced visual acuity may only require that your software support larger text and graphics. For example, the system provides scalable fonts and controls to increase the size of text and graphics. To accommodate users who are blind or have severe impairments, make your software compatible with speech or Braille utilities, described later in this chapter.
Color blindness and other visual impairments may make it difficult for users to distinguish between certain color combinations. This is one reason why color is not recommended as the only means of conveying information. Always use color as an additive or enhancing property.
Users who are deaf or hard-of-hearing are generally unable to detect or interpret auditory output at normal or maximum volume levels. Avoiding the use of auditory output as the only means of communicating information is the best way to support users with this disability. Instead, use audio output only as a redundant, additive property or provide visual output as an option to supplement the audio information. For more information about supporting sound, see "Sound" earlier in this chapter.
Some users have difficulty or are unable to perform certain physical tasks — for example, moving a mouse or simultaneously pressing two keys on the keyboard. Other individuals have a tendency to inadvertently strike multiple keys when targeting a single key. Consideration of physical ability is important not only for users with disabilities, but also for beginning users who need time to master all the motor skills necessary to interact with the interface. The best way to support these users is by supporting all your basic operations using simple keyboard and mouse interfaces.
Users with language disabilities, such as dyslexia, find it difficult to read or write. Spell- or grammar-check utilities can help children, users with writing impairments, and users with a different first language. Supporting accessibility tools and utilities designed for users who are blind can also help those with reading impairments. Most design issues affecting users with oral communication difficulties apply only to utilities specifically designed for speech input.
Cognitive disabilities can take many forms, including perceptual differences and memory impairments. You can accommodate users with these disabilities by allowing them to modify or simplify your software's interface, such as supporting menu or dialog box customization. Similarly, using icons and graphics to illustrate objects and choices can be helpful for users with some types of cognitive impairments.
Some users are sensitive to visual information that alternates its appearance or flashes at particular rates — often the greater the frequency, the greater the problem. However, there is no perfect flash rate. Therefore, base all modulating interfaces on the system's cursor blink rate. Because users can customize this value, a particular frequency can be avoided. If that is not practical, provide your own interface for changing the flash rate.
Note
The GetCaretBlinkTime function provides access to the current cursor blink rate setting. For more information about this function, see the documentation included in the Win32 SDK.