g-object, common-lisp:standard-object, common-lisp:t

None

A gdk-visual object describes a particular video hardware display format. It includes information about the number of bits used for each color, the way the bits are translated into an RGB value for display, and the way the bits are stored in memory. For example, a piece of display hardware might support 24-bit color, 16-bit color, or 8-bit color; meaning 24/16/8-bit pixel sizes. For a given pixel size, pixels can be in different formats; for example the "red" element of an RGB pixel may be in the top 8 bits of the pixel, or may be in the lower 4 bits.

There are several standard visuals. The visual returned by the gdk-screen-system-visual function is the default visual of the system.

A number of functions are provided for determining the "best" available visual. For the purposes of making this determination, higher bit depths are considered better, and for visuals of the same bit depth, :pseudo-color is preferred at 8bpp, otherwise, the visual types are ranked in the order of highest to lowest :direct-color, :true-color, :pseudo-color, :static-color, :grayscale, then :static-gray.