MirOS Manual: XeviGetVisualInfo(3), XeviQueryExtension(3), XeviQueryVersion(3)


XEVI(3X11)                 X FUNCTIONS                 XEVI(3X11)

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 inter-
     faces described below. With the exception of XeviQueryExten-
     sion, 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. Oth-
     erwise, it's a pointer to a list of visuals for which

XFree86                   Version 4.5.0                         1

XEVI(3X11)                 X FUNCTIONS                 XEVI(3X11)

     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.

XFree86                   Version 4.5.0                         2

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