xdbegetvisualinfo(3x11) [redhat man page]

XdbeGetVisualInfo(3X11) 					    X FUNCTIONS 					   XdbeGetVisualInfo(3X11)

NAME

       XdbeGetVisualInfo - Get dbe Visual Informations

SYNOPSIS

       #include <X11/extensions/Xdbe.h>

       XdbeScreenVisualInfo *XdbeGetVisualInfo(
	   Display  *dpy,
	   Drawable *screen_specifiers,
	   int	    *num_screens)

DESCRIPTION

       This function returns information about which visuals support double buffering.	The argument num_screens specifies how many elements there
       are in the screen_specifiers list.  Each drawable in screen_specifiers designates a screen  for	which  the  supported  visuals	are  being
       requested.   If	num_screens  is zero, information for all screens is requested.  In this case, upon return from this function, num_screens
       will be set to the number of screens that were found.  If an error occurs, this function returns NULL, else it returns a pointer to a  list
       of  XdbeScreenVisualInfo  structures  of  length  num_screens.  The nth element in the returned list corresponds to the nth drawable in the
       screen_specifiers list, unless num_screens was passed in with the value zero, in which case the nth element in  the  returned  list  corre-
       sponds to the nth screen of the server, starting with screen zero.  The XdbeScreenVisualInfo structure has the following fields:

	    int 	   count
	    XdbeVisualInfo *visinfo

       count specifies the number of items in visinfo.	visinfo specifies a list of visuals, depths, and performance hints for this screen.

       The XdbeVisualInfo structure has the following fields:

	    VisualID visual
	    int      depth
	    int      perflevel

       visual specifies one visual ID that supports double-buffering.  depth specifies the depth of the visual.  perflevel is a performance hint.

       The  only operation defined on a perflevel is comparison to a perflevel of another visual on the same screen.  The visual having the higher
       perflevel is likely to have better double-buffering graphics performance than the visual  having  the  lower  perflevel.   Nothing  can	be
       deduced from the following: the magnitude of the difference of two perflevels, a perflevel value in isolation, or comparing perflevels from
       different servers.

ERRORS

       BadDrawable
	      One or more values passed in screen_specifiers is not a valid drawable.

SEE ALSO

       DBE, XdbeAllocateBackBufferName(), XdbeBeginIdiom(),  XdbeDeallocateBackBufferName(),  XdbeEndIdiom(),  XdbeFreeVisualInfo(),  XdbeGetBack-
       BufferAttributes(), XdbeQueryExtension(), XdbeSwapBuffers().

X Version 11							    Release 6.6 					   XdbeGetVisualInfo(3X11)

XGetVisualInfo(3X11)						     MIT X11R4						      XGetVisualInfo(3X11)

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

Syntax
       XVisualInfo *XGetVisualInfo(display, vinfo_mask, vinfo_template, nitems_return)
	  Display *display;
	  long vinfo_mask;
	  XVisualInfo *vinfo_template;
	  int *nitems_return;

       Status XMatchVisualInfo(display, screen, depth, class, vinfo_return)
	  Display *display;
	  int screen;
	  int depth;
	  int class;
	  XVisualInfo *vinfo_return;

       VisualID XVisualIDFromVisual(visual)
	   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 function returns a list of visual structures that match the attributes specified by vinfo_template.	If no visual structures match the
       template using the specified vinfo_mask, returns a NULL.  To free the data returned by this function, use

       The 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, returns nonzero and the
       information on the visual to vinfo_return.  Otherwise, when a visual is not found, returns zero.

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

Structures
       The structure contains:

       /* Visual information mask bits */

       #define				     0x0
       #define				     0x1
       #define				     0x2

       #define				     0x4
       #define				     0x8
       #define				     0x10
       #define				     0x20
       #define				     0x40
       #define				     0x80
       #define				     0x100
       #define				     0x1FF

       /* Values */

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

See Also
       XFree(3X11)
       X Window System: The Complete Reference, Second Edition, Robert W. Scheifler and James Gettys

															      XGetVisualInfo(3X11)