<s>
In	O
the	O
X	B-Operating_System
Window	I-Operating_System
System	I-Operating_System
,	O
the	O
X	B-Operating_System
Nonrectangular	O
Window	O
Shape	B-Device
Extension	I-Device
allows	O
windows	O
to	O
be	O
given	O
arbitrary	O
,	O
non-rectangular	O
shapes	O
.	O
</s>
<s>
Two	O
well-known	O
applets	O
that	O
use	O
the	O
shape	B-Device
extension	I-Device
are	O
oclock	O
,	O
which	O
is	O
a	O
simple	O
round	O
analog	O
clock	O
,	O
and	O
xeyes	O
,	O
which	O
shows	O
two	O
googly	O
eyes	O
that	O
follow	O
the	O
cursor	B-Application
on	O
the	O
screen	O
as	O
if	O
they	O
were	O
watching	O
it	O
.	O
</s>
<s>
Most	O
X	B-Operating_System
systems	O
have	O
one	O
or	O
the	O
other	O
(	O
or	O
both	O
)	O
in	O
their	O
standard	O
installations	O
.	O
</s>
<s>
In	O
addition	O
,	O
some	O
window	O
managers	O
use	O
the	O
shape	B-Device
extension	I-Device
to	O
draw	O
non-rectangular	O
icons	O
.	O
</s>
<s>
by	O
sending	O
the	O
X	B-Operating_System
display	O
server	O
either	O
a	O
list	O
of	O
rectangles	O
or	O
a	O
pixmap	O
of	O
color	O
depth	O
one	O
(	O
a	O
black-and-white	O
pixmap	O
)	O
.	O
</s>
<s>
These	O
two	O
areas	O
are	O
defined	O
even	O
for	O
windows	O
not	O
using	O
the	O
shape	B-Device
extension	I-Device
:	O
the	O
clipping	O
region	O
is	O
the	O
area	O
that	O
can	O
be	O
used	O
for	O
drawing	O
,	O
the	O
bounding	O
region	O
is	O
the	O
total	O
area	O
covered	O
by	O
the	O
window	O
(	O
that	O
is	O
,	O
the	O
clipping	O
region	O
plus	O
the	O
border	O
)	O
.	O
</s>
<s>
The	O
shape	B-Device
extension	I-Device
allows	O
defining	O
two	O
independent	O
shapes	O
for	O
these	O
two	O
regions	O
.	O
</s>
<s>
Both	O
the	O
clipping	O
and	O
bounding	O
are	O
associated	O
,	O
in	O
the	O
shape	B-Device
extension	I-Device
,	O
two	O
areas	O
:	O
a	O
default	O
rectangular	O
region	O
and	O
a	O
possibly	O
non-rectangular	O
client	O
region	O
,	O
defined	O
and	O
changed	O
by	O
the	O
client	O
as	O
specified	O
above	O
.	O
</s>
