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XEVI(3)                                          X FUNCTIONS                                         XEVI(3)



NAME
       XeviQueryExtension, XeviQueryVersion, XeviGetVisualInfo - X Extended Visual Information functions

SYNOPSIS
       #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);

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

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

       XeviQueryExtension  returns  True  if  the  Extended Visual Information extension is available on the
       given display.  A client must call XeviQueryExtension before calling any other EVI function in  order
       to negotiate a compatible protocol version; otherwise the client will get undefined 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 returned 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 sup-porting supporting
       porting overlays and/or underlay planes, and information that allows applications better to determine
       the level of hardware support for multiple colormaps. XeviGetVisualInfo returns Success  if  success-ful, successful,
       ful,  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 elements 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 under-
       lays.

       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 transparency 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_conflicts.  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.


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



X Version 11                                    libXext 1.0.5                                        XEVI(3)