<s>
Pseudo-transparency	B-Device
is	O
a	O
term	O
used	O
for	O
X	B-Operating_System
Window	I-Operating_System
System	I-Operating_System
clients	O
that	O
simulate	O
the	O
appearance	O
of	O
translucency	O
or	O
transparency	B-Device
by	O
manipulating	O
the	O
same	O
pixmap	O
that	O
has	O
been	O
drawn	O
on	O
the	O
root	O
window	O
,	O
or	O
by	O
instructing	O
the	O
X	B-Operating_System
Server	O
that	O
the	O
Background	O
Pixmap	O
should	O
be	O
inherited	O
from	O
the	O
window	O
's	O
parent	O
.	O
</s>
<s>
Traditionally	O
,	O
the	O
X	B-Operating_System
Window	I-Operating_System
System	I-Operating_System
has	O
lagged	O
behind	O
other	O
windowing	O
systems	O
in	O
adding	O
purely	O
eye	O
candy	O
or	O
aesthetic	O
features	O
,	O
such	O
as	O
window	O
translucency	O
.	O
</s>
<s>
This	O
has	O
encouraged	O
developers	B-Application
to	O
develop	O
kludges	B-Architecture
to	O
overcome	O
this	O
limitation	O
.	O
</s>
<s>
This	O
pseudo-transparency	B-Device
,	O
so	O
called	O
as	O
the	O
background	O
pixmap	O
of	O
the	O
root	O
window	O
is	O
visible	O
(	O
analogous	O
to	O
desktop	O
wallpaper	O
)	O
rather	O
than	O
any	O
obscured	O
windows	O
,	O
allows	O
users	O
to	O
make	O
windows	O
look	O
less	O
imposing	O
(	O
such	O
as	O
Terminal	B-Application
emulators	I-Application
,	O
which	O
usually	O
comprise	O
large	O
chunks	O
of	O
text	O
)	O
,	O
and	O
to	O
integrate	O
the	O
appearance	O
of	O
windows	O
with	O
their	O
desktop	O
themes	O
.	O
</s>
<s>
There	O
are	O
three	O
common	O
methods	O
for	O
achieving	O
pseudo-transparency	B-Device
using	O
Xlib	B-Language
,	O
each	O
with	O
its	O
own	O
advantages	O
and	O
drawbacks	O
.	O
</s>
<s>
Unfortunately	O
,	O
using	O
this	O
method	O
,	O
the	O
X	B-Operating_System
server	O
permits	O
very	O
few	O
operations	O
to	O
be	O
performed	O
on	O
the	O
background	O
pixmap	O
(	O
such	O
as	O
XOR	B-Application
)	O
,	O
preventing	O
clients	O
from	O
implementing	O
any	O
sort	O
of	O
advanced	O
image	O
filtering	O
.	O
</s>
<s>
Using	O
this	O
information	O
,	O
a	O
client	O
can	O
paint	O
a	O
section	O
of	O
the	O
image	O
(	O
corresponding	O
to	O
the	O
size	O
and	O
position	O
of	O
the	O
window	O
)	O
onto	O
its	O
background	O
,	O
achieving	O
the	O
effect	O
of	O
transparency	B-Device
.	O
</s>
<s>
This	O
method	O
uses	O
the	O
most	O
memory	B-General_Concept
,	O
but	O
has	O
the	O
advantage	O
of	O
allowing	O
clients	O
to	O
perform	O
any	O
operation	O
,	O
such	O
as	O
tinting	O
or	O
shading	B-General_Concept
,	O
on	O
the	O
image	O
data	O
.	O
</s>
<s>
XCopyArea	O
can	O
achieve	O
a	O
more	O
realistic	O
transparency	B-Device
effect	O
in	O
that	O
it	O
can	O
include	O
obscured	O
windows	O
,	O
but	O
with	O
the	O
significant	O
disadvantage	O
that	O
it	O
is	O
only	O
usable	O
with	O
modal	O
windows	O
.	O
</s>
<s>
This	O
method	O
simply	O
uses	O
the	O
XCopyArea( )	O
function	O
to	O
take	O
a	O
partial	O
screenshot	B-Application
for	O
use	O
as	O
the	O
window	O
's	O
background	O
pixmap	O
.	O
</s>
<s>
Recent	O
technologies	O
such	O
as	O
DirectFB	B-Application
,	O
Direct	B-Application
Rendering	I-Application
Infrastructure	I-Application
,	O
and	O
hardware	O
compositing	O
via	O
OpenGL	B-Application
allow	O
X	B-Operating_System
client	O
applications	O
to	O
utilize	O
true	O
alpha	B-Algorithm
transparency	I-Algorithm
.	O
</s>
