<s>
XQuartz	B-Operating_System
is	O
an	O
open-source	B-Application
version	O
of	O
the	O
X.Org	B-Operating_System
X	I-Operating_System
server	I-Operating_System
,	O
a	O
component	O
of	O
the	O
X	B-Operating_System
Window	I-Operating_System
System	I-Operating_System
(	O
X11	B-Operating_System
,	O
or	O
shortened	O
to	O
simply	O
X	B-Operating_System
,	O
and	O
sometimes	O
informally	O
X-Windows	B-Operating_System
)	O
that	O
runs	O
on	O
macOS	B-Application
.	O
</s>
<s>
It	O
formally	O
replaced	O
Apple	O
's	O
internal	O
X11	B-Operating_System
app	O
.	O
</s>
<s>
The	O
name	O
"	O
XQuartz	B-Operating_System
"	O
derives	O
from	O
Quartz	B-Operating_System
,	O
part	O
of	O
the	O
macOS	B-Application
Core	B-Operating_System
Graphics	I-Operating_System
framework	O
,	O
to	O
which	O
XQuartz	B-Operating_System
connects	O
these	O
applications	O
.	O
</s>
<s>
XQuartz	B-Operating_System
allows	O
cross-platform	B-Operating_System
applications	O
using	O
X11	B-Operating_System
for	O
the	O
GUI	B-Application
to	O
run	O
on	O
macOS	B-Application
,	O
many	O
of	O
which	O
are	O
not	O
specifically	O
designed	O
for	O
macOS	B-Application
.	O
</s>
<s>
X11.app	B-Operating_System
was	O
initially	O
available	O
as	O
a	O
downloadable	O
public	O
beta	O
for	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
10.2	I-Operating_System
Jaguar	I-Operating_System
and	O
later	O
included	O
as	O
a	O
standard	O
package	O
for	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
10.3	I-Operating_System
Panther	I-Operating_System
.	O
</s>
<s>
In	O
Mac	B-Application
OS	I-Application
X	I-Application
10.4	I-Application
Tiger	I-Application
X11.app	B-Operating_System
was	O
an	O
optional	O
install	O
included	O
on	O
the	O
install	O
DVD	O
.	O
</s>
<s>
Mac	B-Application
OS	I-Application
X	I-Application
10.5	I-Application
Leopard	I-Application
,	O
Mac	B-Device
OS	I-Device
X	I-Device
10.6	I-Device
Snow	I-Device
Leopard	I-Device
,	O
and	O
Mac	B-Application
OS	I-Application
X	I-Application
10.7	I-Application
Lion	I-Application
installed	O
X11.app	B-Operating_System
by	O
default	O
,	O
but	O
from	O
OS	B-Operating_System
X	I-Operating_System
10.8	I-Operating_System
Mountain	I-Operating_System
Lion	I-Operating_System
on	O
Apple	O
dropped	O
dedicated	O
support	O
for	O
X11.app	B-Operating_System
,	O
with	O
users	O
being	O
directed	O
to	O
the	O
open	B-Application
source	I-Application
XQuartz	B-Operating_System
project	O
(	O
to	O
which	O
Apple	O
contributes	O
)	O
instead	O
.	O
</s>
<s>
In	O
Mac	B-Application
OS	I-Application
X	I-Application
10.4	I-Application
Tiger	I-Application
,	O
Apple	O
's	O
X11	B-Operating_System
implemented	O
X11	B-Device
protocol	I-Device
release	O
6.6	O
(	O
X11R6.6	O
)	O
.	O
</s>
<s>
This	O
implementation	O
includes	O
an	O
XFree86	B-Device
4.4	O
based	O
X11	B-Operating_System
window	O
server	O
,	O
Quartz	B-Operating_System
rootless	O
window	O
manager	O
,	O
libraries	O
,	O
and	O
basic	O
utilities	O
such	O
as	O
xterm	B-Language
.	O
</s>
<s>
"	O
Rootless	O
"	O
means	O
that	O
X	B-Operating_System
window	I-Operating_System
applications	O
show	O
up	O
on	O
the	O
Quartz	B-Operating_System
desktop	O
,	O
appearing	O
like	O
any	O
other	O
windowed	O
Quartz	B-Operating_System
application	O
(	O
that	O
is	O
,	O
not	O
in	O
a	O
virtual	O
desktop	O
contained	O
within	O
another	O
window	O
)	O
.	O
</s>
<s>
In	O
Mac	B-Application
OS	I-Application
X	I-Application
Leopard	I-Application
,	O
X11	B-Operating_System
was	O
updated	O
to	O
use	O
X.Org	B-Operating_System
Server	I-Operating_System
(	O
X11R7.2	O
)	O
rather	O
than	O
XFree86	B-Device
.	O
</s>
<s>
The	O
source	O
code	O
for	O
X11	B-Operating_System
is	O
available	O
from	O
Apple	O
.	O
</s>
<s>
Some	O
source	O
code	O
is	O
available	O
under	O
the	O
Apple	B-License
Public	I-License
Source	I-License
License	I-License
while	O
the	O
bulk	O
is	O
licensed	O
under	O
the	B-License
MIT	I-License
License	I-License
.	O
</s>
<s>
The	O
current	O
version	O
of	O
XQuartz	B-Operating_System
is	O
a	O
DDX	O
(	O
Device	O
Dependent	O
X	B-Operating_System
)	O
included	O
in	O
the	O
X.Org	B-Operating_System
Server	I-Operating_System
and	O
implements	O
support	O
for	O
hardware-accelerated	O
2D	O
graphics	O
(	O
in	O
versions	O
prior	O
to	O
2.1	O
)	O
,	O
hardware	O
OpenGL	B-Application
acceleration	O
and	O
integration	O
with	O
Aqua	B-Application
,	O
the	O
macOS	B-Application
graphical	B-Application
user	I-Application
interface	I-Application
(	O
GUI	B-Application
)	O
.	O
</s>
<s>
As	O
of	O
version	O
2.8.0	O
,	O
XQuartz	B-Operating_System
does	O
not	O
provide	O
support	O
for	O
high-resolution	O
Retina	B-Operating_System
displays	I-Operating_System
to	O
X11	B-Operating_System
apps	O
,	O
which	O
run	O
in	O
pixel-doubled	O
mode	O
on	O
high-resolution	O
displays	O
.	O
</s>
