Allow global configuration to highlight the following four classes of information in each viewport: the selection, content focus, enabled elements, and recently visited links.
For graphical user interfaces, as part of satisfying provision one of this checkpoint, allow at least one configuration where the highlight mechanisms for the four classes of information:
differ from each other, and
do not rely on rendered text foreground and background colors alone.
For graphical user interfaces, as part of satisfying provision one of this checkpoint, if a highlight mechanism involves text size, font family, rendered text foreground and background colors, or text decorations, offer at least the following range of values:
for text size, the range required by provision three of checkpoint 4.1.
for font family, the range required by provision three of checkpoint 4.2.
for text foreground and background colors and decorations, the range offered by the conventional utility available in the operating environment for users to choose rendered text colors or decorations (e.g., the standard font and color dialog box resources supported by the operating system). If no such utility is available, the range supported by the conventional APIs of the operating environment for specifying text colors or drawing text.
Highlight enabled elements according to the granularity specified in the format. For example, an HTML user agent rendering a PNG image as part of a client-side image map is only required to highlight the image as a whole, not each enabled region. An SVG user agent rendering an SVG image with embedded graphical links is required to highlight each (enabled) link that may be rendered independently according to the SVG specification.