sgiXnmbxGetExtendedVisuUNIXfSystsgiXnmbxGetExtendedVisualInfo(3X)
NAME
sgiXnmbxGetExtendedVisualInfo,
sgiXnmbxMatchExtendedVisualInfo,
sgiXnmbxGetVisualCapabilities - obtain NMBX extended visual
information
SYNTAX
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/extensions/sgiXnmbx.h>
XVisualInfo*
sgiXnmbxGetExtendedVisualInfo(dpy, vinfoMask, vinfoTemplate, nitems,
nCriterion, criterion)
Display *dpy;
long vinfoMask;
XVisualInfo *vinfoTemplate;
int *nitems;
int nCriterion;
sgiXnmbxCapability *criterion;
Status
sgiXnmbxMatchExtendedVisualInfo(dpy, screen, depth, class,
nCriterion, criterion, vinfo_return)
Display *dpy;
int screen;
int depth;
int class;
int nCriterion;
sgiXnmbxCapability *criterion;
XVisualInfo *vinfo_return;
sgiXnmbxCapability*
sgiXnmbxGetVisualCapabilities(dpy, visual, nCapabilities)
Display *dpy;
Visual *visual;
int *nCapabilities;
ARGUMENTS
dpy Specifies the connection to the X server.
vinfoMask Specifies the visual mask value.
vinfoTemplate
Specifies the core visual attributes that are to
be used in matching the visual structures.
nitems Returns the number of matching visual structures.
nCriterion
Specifies the number of extended capability match
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criteria.
criterion Specifies an array of extended capability match
criteria. to use in selecting visuals.
screen Specifies the screen.
depth Specifies the depth of the screen.
class Specifies the visual type.
vinfo_return
Returns the matched visual information.
visual Specifies the visual.
nCapabilities
Returns the number of capabilities for the visual.
DESCRIPTION
sgiXnmbxGetExtendedVisualInfo works like XGetVisualInfo but
also supports queries involving NMBX extended visual
capabilities. Two additional parameters nCriterion and
criterion allow match criteria to be specified. criterion
is of type sgiXnmbxCapability which is a structure:
typedef struct {
Atom atom;
unsigned long value;
int matchCriterion;
} sgiXnmbxCapability;
The atom field should be filled in with the atom value for
the interned string naming the capability descriptor. If the
atom field is None, the criterion is ignored. The
matchCriterion field is an enumerated value:
#define sgiNMBX_Equal 0
#define sgiNMBX_NotEqual 1
#define sgiNMBX_Greater 2
#define sgiNMBX_GreaterOrEqual 3
#define sgiNMBX_Less 4
#define sgiNMBX_LessOrEqual 5
#define sgiNMBX_Present 6
#define sgiNMBX_NotPresent 7
The value field specifies a value to be used according to
the match criterion. sgiNMBX_Present and sgiNMBX_NotPresent
ignore the value and only test existence or non-existence of
the capability descriptor (independet of value).
If the call is unsuccessful or no matching visuals are
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found, NULL will be returned. Otherwise,
sgiXnmbxGetExtendedVisualInfo will return a list of visuals
and update nitems to reflect the number of visuals returned.
Each visual on the list will match the template and meet all
extended capability match criteria specified.
sgiXnmbxGetExtendedVisualInfo may be used independent of
whether the NMBX extension is present or not. When the
extension is not present, it is assumed none of the server
visual have any NMBX capability descriptors.
The memory returned by sgiXnmbxGetExtendedVisualInfo should
be freed when no longer needed with XFree.
sgiXnmbxMatchExtendedVisualInfo works like XMatchVisualInfo
but takes two additional parameters nCriterion and criterion
which allow match criteria to be specified. The match
criteria operate like in sgiXnmbxGetExtendedVisualInfo.
sgiXnmbxGetVisualCapabilities queries the NMBX extended
visual capabilities of the specified visual.
If the call is unsuccessful or the visual has no NMBX
capability descriptors, NULL will be returned. Otherwise,
nCapabilities reflects the number of elements in an array of
type sgiXnmbxCapability returned. The client is expected to
un-intern the returned atoms to determine the names of the
returned capabilities. The returned matchCriterion fields
will always be set to sgiNMBX_Equal.
sgiXnmbxGetVisualCapabilities may be used indepednet of
whether the NMBX extension is present or not. When the
extension is not present, it is assumed none of the server
visual have any NMBX capability descriptors so NULL is
always returned.
The memory returned by sgiXnmbxGetVisualCapabilities should
be freed when no longer needed with XFree.
EXAMPLE
The following example shows how to use
sgiXnmbxGetExtendedVisualInfo to find all the visual able to
perform NMBX double buffering and able to use OpenGL
rendering which are PseudoColor on the default screen:
Display *dpy;
XVisualInfo template;
sgiXnmbxCapability cap[2];
int nVisuals;
Atom double_buffer_atom, opengl_atom;
XVisualInfo *visuals;
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/* intern atoms */
double_buffer_atom = XInternAtom(dpy, "MAX_DISPLAY_BUFFERS", 1);
opengl_atom = XInternAtom(dpy, "OPENGL_CAPABLE", 1);
/* set up match criteria */
cap[0].atom = double_buffer_atom;
cap[0].value = 2;
cap[0].matchCriterion = sgiNMBX_GreaterOrEqual;
cap[1].atom = opengl_atom;
cap[1].matchCriterion = sgiNMBX_Present;
/* setup standard visual info template */
template.screen = DefaultScreen(dpy);
template.class = PseudoColor;
visuals = sgiXnmbxGetExtendedVisualInfo(dpy, VisualScreenMask|
VisualClassMask, &template, &nVisuals, 2, cap);
NOTES
This extension is not supported by XFree86(1).
SEE ALSO
XGetVisualInfo(3X)
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