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xdbegetvisualinfo(3x11) [xfree86 man page]

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

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(). XFree86 Version 4.7.0 XdbeGetVisualInfo(3X11)

Check Out this Related Man Page

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

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

       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;

       class	 Specifies the class of the screen.

       depth	 Specifies the depth of the screen.

       display	 Specifies the connection to the X server.

		 Returns the number of matching visual structures.

       screen	 Specifies the screen.

       visual	 Specifies the visual type.

		 Specifies the visual mask value.

		 Returns the matched visual information.

		 Specifies the visual attributes that are to be used in matching the visual structures.

       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.

       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
       X Window System: The Complete Reference, Second Edition, Robert W. Scheifler and James Gettys

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