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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 informa-
tion 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 XSetEx-
tensionErrorHandler 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 col-
ormaps. 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 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_TRANS-
PARENCY_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 trans-
parency_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 1.0.5 XEVI(3) |
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