XGetVisualInfo (3) - Linux Manuals

XGetVisualInfo: obtain visual information and visual structure

Command to display XGetVisualInfo manual in Linux: $ man 3 XGetVisualInfo

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;