Common Desktop Environment: Style Guide and Certification Checklist

Visual Disabilities

Visual disabilities may require use of tools ranging from reading glasses, to large-sized displays and fonts, to screen reading software that enables completely blind users to navigate and hear what is on the screen.

Reading small fonts can be challenging for users with low vision. All fonts, including those in text panes, menus, labels, and information messages should be easily configurable by the user--font size and type should never be hard coded.

Interpreting information that depends upon color (for example, red = stop, green = go) can be difficult for people with visual impairments. A significant number of people are color blind and are unable to see differences between some colors. For these reasons, never use color as the only source of information.

In addition to being difficult to interpret, some background and text color combinations can result in text that is difficult to read for users with visual impairments. Again, the key is to provide choice. Never hard code color choices. Users should always have the capability to override default colors, so they can choose the colors that work best for them.

Provide meaningful names for every widget instance. Meaningful names help screen reading software give useful information to users with visual impairments. Rather than naming an eraser graphic widget5, for example, call it eraser or some other such descriptive name.

Without such descriptive information, blind or low-vision users cannot interpret unlabeled, graphically labeled, or custom widgets. Providing this information is a requirement for access in such cases. As an added bonus, meaningful widget names make for code that is easier to debug.

Finally, remember that many users with visual disabilities depend upon keyboard navigation and control, and they will not be using a pointing device.




Colors should not be hard coded. 



Graphic attributes, such as line, border, and shadow, should not be hard coded. 



Font sizes and styles should not be hard coded. 



All application code uses descriptive names for widgets. Such descriptive names for widgets using graphics instead of text (for example, palette items and icons) allow screen reading software to provide descriptive information to blind users.