Gdk.Visual Class
Describes a particular video hardware display format.

See Also: Visual Members


public class Visual : GLib.Object


A Gdk.Visual 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.

Usually you can avoid thinking about visuals in GTK+. Visuals are useful to interpret the contents of a Gdk.Image, but you should avoid GdkImage precisely because its contents depend on the display hardware; use Gdk.Pixbuf instead, for all but the most low-level purposes. Also, anytime you provide a Gdk.Colormap, the visual is implied as part of the colormap (Colormap.Visual), so you won't have to provide a visual in addition.

There are several standard visuals. The visual returned by Visual.System is the system's default visual. Rgb.Visual return the visual most suited to displaying full-color image data. If you use the calls in Gdk.RGB, you should create your windows using this visual (and the colormap returned by Rgb.Colormap).

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, VisualType.PseudoColor is preferred at 8bpp, otherwise, the visual types are ranked in the order of (highest to lowest) VisualType.DirectColorVisualType.TrueColor, VisualType.PseudoColor, k.VisualType.StaticColor, k.VisualType.Grayscale, then VisualType.StaticGray.


Namespace: Gdk
Assembly: gdk-sharp (in gdk-sharp.dll)
Assembly Versions: