XGetVisualInfo

Section: XLIB FUNCTIONS (3)
Updated: libX11 1.3
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NAME

XGetVisualInfo, XMatchVisualInfo, XVisualIDFromVisual, XVisualInfo - obtain visual information and visual structure

SYNTAX

: XVisualInfo *XGetVisualInfo(Display *display, long vinfo_mask, XVisualInfo *vinfo_template, int *nitems_return);
: Status XMatchVisualInfo(Display *display, int screen, int depth, int class, XVisualInfo *vinfo_return);
: VisualID XVisualIDFromVisual(Visual *visual);

ARGUMENTS

class: Specifies the class of the screen.
depth: Specifies the depth of the screen.
display: Specifies the connection to the X server.
nitems_return: Returns the number of matching visual structures.
screen: Specifies the screen.
visual: Specifies the visual type.
vinfo_mask: Specifies the visual mask value.
vinfo_return: Returns the matched visual information.
vinfo_template: Specifies the visual attributes that are to be used in matching the visual structures.

DESCRIPTION

The XGetVisualInfo function returns a list of visual structures that have attributes equal to the attributes specified by vinfo_template. If no visual structures match the template using the specified vinfo_mask, XGetVisualInfo returns a NULL. To free the data returned by this function, use XFree.

The XMatchVisualInfo function returns the visual information for a visual that matches the specified depth and class for a screen. Because multiple visuals that match the specified depth and class can exist, the exact visual chosen is undefined. If a visual is found, XMatchVisualInfo returns nonzero and the information on the visual to vinfo_return. Otherwise, when a visual is not found, XMatchVisualInfo returns zero.

The XVisualIDFromVisual function returns the visual ID for the specified visual type.

STRUCTURES

The XVisualInfo structure contains:

/* Visual information mask bits */

#define VisualNoMask 0x0

#define VisualIDMask 0x1

#define VisualScreenMask 0x2

#define VisualDepthMask 0x4

#define VisualClassMask 0x8

#define VisualRedMaskMask 0x10

#define VisualGreenMaskMask 0x20

#define VisualBlueMaskMask 0x40

#define VisualColormapSizeMask 0x80

#define VisualBitsPerRGBMask 0x100

#define VisualAllMask 0x1FF


/* Values */

typedef struct {
     Visual *visual;
     VisualID visualid;
     int screen;
     int depth;
     int class;
     unsigned long red_mask;
     unsigned long green_mask;
     unsigned long blue_mask;
     int colormap_size;
     int bits_per_rgb;
} XVisualInfo;