<s>
The	O
FOX	B-Language
toolkit	I-Language
is	O
an	O
open-source	B-Application
,	O
cross-platform	B-Operating_System
widget	B-Library
toolkit	I-Library
,	O
i.e.	O
</s>
<s>
a	O
library	O
of	O
basic	O
elements	O
for	O
building	O
a	O
graphical	B-Application
user	I-Application
interface	I-Application
(	O
GUI	B-Application
)	O
.	O
</s>
<s>
FOX	O
stands	O
for	O
Free	O
Objects	O
for	O
X	B-Operating_System
.	O
</s>
<s>
It	O
features	O
a	O
hard-wired	O
Windows	O
95-style	O
theme	B-Application
available	O
for	O
both	O
Microsoft	B-Application
Windows	I-Application
itself	O
as	O
well	O
as	O
the	O
X	B-Operating_System
Window	I-Operating_System
System	I-Operating_System
(	O
which	O
is	O
used	O
on	O
many	O
UNIX	B-Application
and	O
UNIX-like	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
)	O
.	O
</s>
<s>
The	O
FOX	B-Language
toolkit	I-Language
has	O
been	O
released	O
under	O
the	O
GNU	B-Application
Lesser	I-Application
General	I-Application
Public	I-Application
Licence	I-Application
.	O
</s>
<s>
The	O
FOX	B-Language
toolkit	I-Language
is	O
written	O
in	O
C++	B-Language
,	O
with	O
language	B-Application
bindings	I-Application
available	O
for	O
Python	B-Language
,	O
Ruby	B-Language
and	O
Eiffel	B-Language
.	O
</s>
<s>
The	O
FOX	O
source	O
code	O
distribution	O
supports	O
building	O
with	O
many	O
different	O
(	O
commercial	O
and	O
free	O
)	O
C++	B-Language
compilers	O
.	O
</s>
<s>
FOX	O
differentiates	O
itself	O
in	O
the	O
following	O
way	O
from	O
other	O
cross-platform	B-Operating_System
toolkits	O
:	O
</s>
<s>
Tk	B-Application
is	O
a	O
cross-platform	B-Operating_System
toolkit	O
but	O
does	O
not	O
have	O
all	O
of	O
the	O
widgets	O
that	O
FOX	O
considers	O
desirable	O
.	O
</s>
<s>
Qt	B-Language
up	O
to	O
version	O
4.5	O
used	O
to	O
have	O
a	O
licensing	O
model	O
that	O
required	O
a	O
commercial	O
license	O
in	O
some	O
cases	O
where	O
FOX	O
would	O
not	O
.	O
</s>
<s>
wxWidgets	B-Language
promotes	O
the	O
use	O
of	O
native	O
widgets	O
on	O
each	O
supported	O
platform	O
.	O
</s>
<s>
FLTK	B-Language
is	O
a	O
fast	O
,	O
low-footprint	O
library	O
that	O
supports	O
rapid	O
application	O
development	O
,	O
and	O
requires	O
less	O
code	O
to	O
use	O
,	O
but	O
lacks	O
advanced	O
widgets	O
.	O
</s>
<s>
All	O
of	O
these	O
toolkits	O
have	O
some	O
support	O
for	O
programming	O
natively	O
on	O
the	O
classic	B-Application
Mac	I-Application
OS	I-Application
and/or	O
macOS	B-Application
platforms	O
,	O
which	O
FOX	O
currently	O
does	O
not	O
support	O
.	O
</s>
<s>
FOX	O
uses	O
a	O
technique	O
similar	O
to	O
the	O
Java	O
Swing-style	O
approach	O
to	O
display	O
a	O
graphical	B-Application
user	I-Application
interface	I-Application
to	O
the	O
screen	O
,	O
using	O
only	O
graphical	O
primitives	O
available	O
on	O
that	O
platform	O
,	O
as	O
opposed	O
to	O
the	O
original	O
Java	O
AWT-style	O
approach	O
which	O
used	O
native	O
widgets	O
.	O
</s>
<s>
This	O
means	O
that	O
applications	O
will	O
have	O
a	O
similar	O
look	B-Application
and	I-Application
feel	I-Application
across	O
platforms	O
.	O
</s>
<s>
On	O
the	O
downside	O
,	O
it	O
usually	O
means	O
that	O
FOX	O
applications	O
will	O
look	B-Application
and	I-Application
feel	I-Application
different	O
from	O
native	O
applications	O
for	O
those	O
platforms	O
,	O
which	O
some	O
users	O
may	O
find	O
confusing	O
.	O
</s>
<s>
Also	O
,	O
certain	O
native	O
platform	O
features	O
may	O
not	O
be	O
available	O
immediately	O
,	O
such	O
as	O
comprehensive	O
printing	O
support	O
or	O
internationalized	O
input	O
handling	O
,	O
because	O
they	O
will	O
need	O
to	O
be	O
re-implemented	O
in	O
a	O
cross-platform	B-Operating_System
way	O
before	O
they	O
can	O
be	O
used	O
in	O
FOX	O
.	O
</s>
<s>
Some	O
applications	O
,	O
like	O
Xfe	B-Application
File	I-Application
Manager	I-Application
,	O
allow	O
changing	O
the	O
color	O
scheme	O
to	O
better	O
integrate	O
with	O
the	O
system	O
's	O
theme	B-Application
colors	O
.	O
</s>
<s>
It	O
ships	O
with	O
the	O
main	O
FOX	B-Language
Toolkit	I-Language
package	O
.	O
</s>
<s>
The	O
FOX	O
messaging	O
system	O
simplifies	O
the	O
GUI	B-Application
update	O
strategy	O
:	O
during	O
widget	O
update	O
,	O
the	O
widgets	O
can	O
ask	O
from	O
their	O
targets	O
to	O
update	O
them	O
.	O
</s>
<s>
This	O
strategy	O
separates	O
the	O
GUI	B-Application
update	O
from	O
data	O
changes	O
,	O
making	O
the	O
GUI	B-Application
a	O
real-time	O
reflection	O
of	O
the	O
underlying	O
data	O
structures	O
.	O
</s>
<s>
Under	O
hood	O
it	O
depends	O
on	O
the	O
cross-platform	B-Operating_System
libraries	O
,	O
which	O
include	O
the	O
following	O
:	O
</s>
<s>
The	O
following	O
example	O
creates	O
a	O
FOX	O
application	O
and	O
a	O
dialog	O
with	O
a	O
button	O
on	O
C++	B-Language
:	O
</s>
<s>
It	O
is	O
also	O
possible	O
to	O
create	O
dialogs	O
with	O
Python	B-Language
2.2	O
and	O
Ruby	B-Language
:	O
</s>
