NAME¶
XtAllocateGC - obtain a sharable GC with modifiable fields
SYNTAX¶
GC
XtAllocateGC(Widget w, Cardinal depth, XtGCMask
value_mask, XGCValues * values, XtGCMask dynamic_mask,
XtGCMask unused_mask);
ARGUMENTS¶
- values
- Specifies the actual values for this GC.
- value_mask
- Specifies which fields of the values are specified.
- w
- Specifies the widget.
- depth
- Specifies the depth for which the returned GC is valid, or
0.
- dynamic_mask
- Specifies the fields of the GC that will be modified by the
caller.
- unused_mask
- Specifies the fields of the GC that will not be needed by
the caller.
DESCRIPTION¶
The
XtAllocateGC function returns a sharable GC that may be modified by
the client. The
screen field of the specified widget or of the nearest
widget ancestor of the specified object and the specified
depth
argument supply the root and drawable depths for which the GC is to be valid.
If
depth is zero the depth is taken from the
depth field of the
specified widget or of the nearest widget ancestor of the specified object.
The
value_mask argument specifies the fields of the GC that will be
initialized with the respective members of the
values structure. The
dynamic_mask argument specifies fields that the caller intends to
modify during program execution. The caller must ensure that the corresponding
GC field is set prior to each use of the GC. The
unused_mask argument
specifies fields of the GC that are of no interest to the caller. The caller
may make no assumptions about the contents of any fields specified in
unused_mask. The caller may assume that at all times all fields not
specified in either
dynamic_mask or
unused_mask have their
default value if not specified in
value_mask or the value specified by
values. If a field is specified in both
value_mask and
dynamic_mask, the effect is as if it were specified only in
dynamic_mask and then immediately set to the value in
values. If
a field is set in
unused_mask and also in either
value_mask or
dynamic_mask, the specification in
unused_mask is ignored.
XtAllocateGC tries to minimize the number of unique GCs created by
comparing the arguments with those of previous calls and returning an existing
GC when there are no conflicts.
XtAllocateGC may modify and return an
existing GC if it was allocated with a nonzero
unused_mask.
SEE ALSO¶
XtGetGC
X Toolkit Intrinsics - C Language Interface
Xlib - C Language X Interface
