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XEVI(3)				  X FUNCTIONS			       XEVI(3)

       XeviQueryExtension,  XeviQueryVersion,  XeviGetVisualInfo  - X Extended
       Visual Information functions

       #include	<X11/extensions/XEVI.h>

       Bool XeviQueryExtension (Display	*dpy);

       Bool XeviQueryVersion (Display *dpy,
	   int *major_version_return,
	   int *minor_version_return);

       int XeviGetVisualInfo (Display *dpy, VisualID *visual,
	   int n_visual, ExtendedVisualInfo ** evi_return,
	   int * n_info_return);

       The X11 Extended	Visual Information extension (EVI) allows a client  to
       determine  information about core X visuals beyond what the core	proto-
       col provides.

       The EVI application programming library	contains  the  interfaces  de-
       scribed	below.	 With  the  exception of XeviQueryExtension, if	any of
       these routines are called with a	display	that does not support the  ex-
       tension,	 the  ExtensionErrorHandler  (which can	be set with XSetExten-
       sionErrorHandler	and functions the same way as  XSetErrorHandler)  will
       be called and the function will then return.

       XeviQueryExtension  returns True	if the Extended	Visual Information ex-
       tension is available on the given display.  A client  must  call	 Xevi-
       QueryExtension  before calling any other	EVI function in	order to nego-
       tiate a compatible protocol version; otherwise the client will get  un-
       defined behavior	(EVI may or may	not work).

       XeviQueryVersion	 returns  True if the request succeeded; the values of
       the major and minor protocol version supported by the  server  are  re-
       turned in major_version_return and minor_version_return.

       XeviGetVisualInfo  returns a list of ExtendedVisualInfo structures that
       describe	visual information beyond that supported by the	core protocol.
       This  includes  layer information relevant for systems supporting over-
       lays and/or underlay planes, and	information that  allows  applications
       better  to  determine  the  level of hardware support for multiple col-
       ormaps. XeviGetVisualInfo returns Success if successful,	or an X	 error
       otherwise.   If	the  argument visual is	NULL, then information for all
       visuals of all screens is returned. Otherwise, it's a pointer to	a list
       of  visuals for which extended visual information is desired.  n_visual
       is the number of	elements in the	array visual.	evi_return  returns  a
       pointer	to  a list of ExtendedVisualInfo. When done, the client	should
       free the	list using XFree.  n_info_return returns the  number  of  ele-
       ments in	the array evi_return.

       The ExtendedVisualInfo structure	has the	following fields:
	    VisualID	    core_visual_id
	    int		    screen
	    int		    level
	    unsigned int    transparency_type
	    unsigned int    transparency_value
	    unsigned int    min_hw_colormaps
	    unsigned int    max_hw_colormaps
	    unsigned int    num_colormap_conflicts
	    VisualID *	    colormap_conflicts

       The  combination	 of  core_visual_id and	screen number uniquely specify
       the visual being	described.

       level returns the level number for the visual, 0	for normal planes, > 0
       for overlays, < 0 for underlays.

       transparency_type  returns  the	type  of transparency supported	by the
       visual. XEVI_TRANSPARENCY_NONE if  there	 are  no  transparent  pixels,
       XEVI_TRANSPARENCY_PIXEL	if  the	 visual	 supports a transparent	pixel,
       XEVI_TRANSPARENCY_MASK if the visual supports transparent plane(s).

       transparency_value returns the pixel/plane value	to set	for  transpar-
       ency if transparency_type isn't XEVI_TRANSPARENCY_NONE.

       min_hw_colormaps	 and  max_hw_colormaps	return the minimum and maximum
       number of hardware colormaps backing up the visual.

       num_colormap_conflicts returns the number of elements in	 colormap_con-
       flicts.	 This array returns a list of visuals that may cause conflicts
       in the use of the hardware colormap. For	example, if a 12-bit  hardware
       colormap	 is  overloaded	 to support 8-bit colormaps, the corresponding
       8-bit visuals would conflict with the 12-bit visuals.

       XeviGetVisualInfo will return BadValue if passed	an illegal visual  ID,
       BadAccess if the	X server does not respond, BadAlloc if there is	a mem-
       ory allocation failure.

X Version 11			 libXext 1.3.4			       XEVI(3)


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