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