XeviQueryExtension(3X11)XeviQueryExtension(3X11)NAME
XeviQueryExtension, XeviQueryVersion, XeviGetVisualInfo - determine
information about core X visuals
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 );
ARGUMENTS
Specifies the connection to the X server. Returns a pointer to a list
of ExtendedVisualInfo. When done, the client should free the list using
XFree. Returns the value of the major protocol version supported by
the server. Returns the value of the minor protocol version supported
by the server. Returns the number of elements in the evi_return array.
Specifies the number of elements in the visual array. Specifies the
visuals for which the extended visual information is needed. If this
argument is NULL, information for all visuals of all screen is
returned.
DESCRIPTION
The X11 Extended Visual Information extension (EVI) provides informa‐
tion about core X visuals beyond that which the core protocol provides.
The EVI application programming library contains the XeviQueryExten‐
sion, XeviQueryVersion, and XeviGetVisualInfo interfaces. If any of
these routines are called with a display that does not support the
extension (with the exception of the XeviQueryExtension), the Exten‐
sionErrorHandler is called and the function returns. XeviQueryExten‐
sion returns true if the Extended Visual Information extension is
available on the specified display. XeviQueryExtension must be called
before other EVI functions to negotiate a compatible protocol version;
otherwise, the result is undefined behavior. XeviQueryVersion returns
true if the request is successful. The values of the major and minor
protocol version that the server supports are returned in major_ver‐
sion_return and minor_version_return, respectively. XeviGetVisualInfo
returns a list of ExtendedVisualInfo structures which describe visual
information beyond the information supported by the core protocol. The
information includes layer information relevent to systems supporting
overlays and underlays and also information that allows applications to
determine the level of hardware support for multiple colormaps.
XeviGetVisualInfo returns Success if successful, or an X error if
unsuccessful.
NOTES
The ExtensionErrorHandler can be set using XSetExtensionErrorHandler.
It functions the same as XSetErrorHandler.
STRUCTURES
The ExtendedVisualInfo structure contains 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
──────────────────────────────────────
uniquely specify the visual being described. contains the level number
for the visual: 0 for normal planes; > 0 for overlays; < 0 for under‐
lays. contains the type of transparency that the visual supports:
XEVI_TRANSPARENCY_NONE, no transparent pixels XEVI_TRANS‐
PARENCY_PIXEL, supports a transparent pixel XEVI_TRANS‐
PARENCY_MASK, supports transparent plane(s) contains the pixel
or plane value for transparency if transparency_type is not
XEVI_TRANSPARENCY_NONE. contains the minimum number of hardware
colormaps that backup the visual. contains the maximum number
of hardware colormaps that backup the visual. contains the num‐
ber of elements in colormap_conflicts. contains a list of visu‐
als that may cause conflicts using 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.
DIAGNOSTICS
XeviGetVisualInfo returns the following: The server failed to respond.
The server failed to allocate the requested resource or server memory.
The client specified an illegal visual ID.
LEGAL NOTICES
Copyright 1997, Silcon Graphics Computer Systems.
See X(1X) for a full statement of rights and permissions.
SEE ALSOCommands:X(1)XeviQueryExtension(3X11)
