AT&T UNIX™PC Unix System V Users Manual - tenox

WRASTOP ( 3T ) (AT&T UNIX PC only ) WRASTOP ( 3T )
aware of the problems associated with overlapping rectangles: the
memory operations will be done front to back or back to front as
necessary.
The width and height parameters give the rectangle's width and
height in pixels.
The srcop (source operation) and dstop (destination operation)
fields together determine the algorithm which will be applied to
the two rectangles. The basic behavior of rastop conforms to the
following vector description:
dst = dstop( srcop(src,pattern) )
where srcop and dstop are vector functions. There are five source
operations. SRCSRC is the identity function whose value is the
unmodified source rectangle itself. SRCPAT's value is that of the
"pattern" (see below) and bears no relationship to the source.
SRCOR is the inclusive OR of the source and the pattern;
SRCAND, the AND; SRCXOR, the exclusive OR.
DSTSRC is the identity function, returning the result of the
source operation unchanged. DSTAND is the AND of the destination
with the result of the source, DSTOR is the inclusive OR, and
DSRXOR the exclusive OR. DSTCAM AND's the one'scomplement
of the source operation into the destination.
DSTCAM is the inverse of DSTOR: where DSTOR would turn on
pixels, DSTCAM will turn them off.
The pattern field is required for SRCPAT, SRCAND, SRCOR,
and SRCXOR operations only. It points to an array of 16 X 16 l
pixels arranged as 16 consecutive shorts. As with source and destination
rectangles, the LSB of the first short in the vector
corresponds to the upper-left-hand pixel of the pattern. Patterns
are automatically aligned with the destination.
In addition to the wrastop function, there are four pre-defined patterns
: patblack (all zeros), patwhite (all ones), patgray (halftone),
and patltgray (light gray). To reference these patterns,
the calling program should define these patterns as external
unsigned short arrays (unsigned short patblack[ ]).
If the pattern field is set to 0, the operation will take place as if
patblack was specified.
Note that wrastop always refreshes the specified window before
executing to force any character operations to occur in correct
time order.
FILES
fusr /include/sys/window .h
SEE ALSO
tam(3T), window(7).
DIAGNOSTICS
Wrastop returns 0 on success, -1 on failure with errno set to the
error number. Any attempt to issue a wrastop call on a nonbitmap
display will result in a return of -1 with errno left to its
previous value.
- 2-