A desktop environment is the top-level interface that users interact with to launch applications, configure their system, check system information, and switch between open applications. These are the parts of the computing experience that automatically appear after the system is first started, and before any user applications are launched.
The Prime Directive is to communicate with users. The user will generally know what they would like rather than what wouldn’t help or even hinder their experience. Some users may have different ideas of what is “accessible” versus other users. In cases like this, you’ll either need to choose between the two ideas, or give the users a choice between the two (preferable). When it comes to accessibility, choice is never a bad thing. Your users will thank you for giving them something that makes their own experience enjoyable, productive, or both.
This section will concern users who have either only light perception or cannot see anything at all. People who have limited vision will be addressed in another section.
Everything visual must have an audible or haptic representation if it is meaningful. For example, each pixel on the screen does not need to be described in detail, but an important animation, or one that is appealing to sighted users, should be made known to the blind user.
Some users enjoy hearing sounds for things like animations, progress bars and the completion of them, and error messages. Other users like having these things spoken using their screen reader. Others still don’t want to hear these things at all unless they prompt for the information.
Every widget must be labeled with text. If there is a way to give only an accessibility label, that can be done if the widget is only supposed to appear as an image to sighted users. Labels should be brief, like “close”, not overly verbose, like “green close button on a blue background”.
A blind person usually only uses the keyboard to navigate. This means that the keyboard focus must never be trapped anywhere without a clearly communicated exit to the trap. For example, if a user is assigning a keyboard command to an action, the user must be able to escape that, rather than having Escape captured. This can be carried over to other interaction methods, like touch.