Manual Pages for UNIX Operating System command usage for man Xevi

X FUNCTIONS                                           XEVI(3xext)



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

SYNOPSIS
     cc [ flag... ] file... -lXext [ library... ]
     #include 

     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  inter-
     faces  described  below.  With the exception of XeviQueryEx-
     tension, if any of these routines are called with a  display
     that  does  not  support  the  extension,  the  ExtensionEr-
     rorHandler (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 sup-
     ported 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 color-
     maps. 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.



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X FUNCTIONS                                           XEVI(3xext)



     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 tran-
     sparent pixels, XEVI_TRANSPARENCY_PIXEL if the  visual  sup-
     ports  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  color-
     map.  For  example,  if  a 12-bit hardware colormap is over-
     loaded 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.






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X FUNCTIONS                                           XEVI(3xext)



ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Availability                | x11/library/libxext         |
    |_____________________________|_____________________________|
    | Interface Stability         | Committed                   |
    |_____________________________|_____________________________|
    | MT-Level                    | See XInitThreads(3X11)      |
    |_____________________________|_____________________________|










































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