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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 supporting
       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 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 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 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
       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 1.3.4                         XEVI(3)