<s>
Metafont	B-Operating_System
is	O
a	O
description	O
language	O
used	O
to	O
define	O
raster	O
fonts	O
.	O
</s>
<s>
It	O
is	O
also	O
the	O
name	O
of	O
the	O
interpreter	B-Application
that	O
executes	O
Metafont	B-Operating_System
code	O
,	O
generating	O
the	O
bitmap	O
fonts	O
that	O
can	O
be	O
embedded	O
into	O
e.g.	O
</s>
<s>
PostScript	B-Language
.	O
</s>
<s>
Metafont	B-Operating_System
was	O
devised	O
by	O
Donald	O
Knuth	O
as	O
a	O
companion	O
to	O
his	O
TeX	B-Application
typesetting	O
system	O
.	O
</s>
<s>
One	O
of	O
the	O
characteristics	O
of	O
Metafont	B-Operating_System
is	O
that	O
the	O
points	O
defining	O
the	O
shapes	O
of	O
the	O
glyphs	B-Application
—	O
for	O
example	O
top	O
of	O
a	O
stem	O
,	O
or	O
intersection	O
of	O
a	O
stem	O
and	O
crossbar	O
—	O
are	O
defined	O
with	O
geometrical	O
equations	O
;	O
the	O
intent	O
that	O
the	O
three	O
stems	O
of	O
an	O
‘	O
m’	O
are	O
equally	O
spaced	O
horizontally	O
might	O
be	O
expressed	O
as	O
if	O
points	O
1	O
,	O
2	O
,	O
and	O
3	O
are	O
at	O
the	O
bottom	O
ends	O
of	O
the	O
three	O
stems	O
,	O
whereas	O
the	O
intent	O
that	O
they	O
all	O
end	O
on	O
the	O
same	O
vertical	O
position	O
would	O
be	O
.	O
</s>
<s>
Metafont	B-Operating_System
is	O
a	O
macro	O
language	O
,	O
where	O
operations	O
such	O
as	O
"	O
draw	O
a	O
lower	O
case	O
top	O
of	O
stem	O
serif	O
at	O
point	O
4	O
"	O
might	O
appear	O
as	O
one	O
macro	O
instruction	O
(	O
with	O
the	O
point	O
as	O
argument	O
)	O
in	O
the	O
program	O
for	O
a	O
letter	O
.	O
</s>
<s>
For	O
describing	O
shapes	O
,	O
Metafont	B-Operating_System
has	O
a	O
rich	O
set	O
of	O
path	O
construction	O
operations	O
that	O
mostly	O
relieves	O
the	O
user	O
of	O
having	O
to	O
calculate	O
control	O
points	O
.	O
</s>
<s>
Many	O
families	O
of	O
Metafont	B-Operating_System
fonts	O
are	O
set	O
up	O
so	O
that	O
the	O
main	O
source	O
file	O
for	O
a	O
font	O
only	O
defines	O
a	O
small	O
number	O
of	O
design	O
parameters	O
(	O
x-height	O
,	O
em	O
width	O
,	O
slant	O
,	O
vertical	O
stroke	O
width	O
,	O
etc	O
.	O
</s>
<s>
)	O
,	O
then	O
calling	O
a	O
separate	O
source	O
file	O
common	O
for	O
a	O
whole	O
range	O
of	O
fonts	O
to	O
actually	O
draw	O
the	O
individual	O
glyphs	B-Application
;	O
this	O
is	O
the	O
meta	O
aspect	O
of	O
the	O
system	O
.	O
</s>
<s>
Metafont	B-Operating_System
is	O
most	O
often	O
run	O
as	O
a	O
helper	O
to	O
output	O
device	O
(	O
printer	O
,	O
screen	O
)	O
drivers	O
;	O
in	O
those	O
cases	O
,	O
its	O
job	O
is	O
to	O
generate	O
bitmaps	O
for	O
a	O
font	O
for	O
a	O
specific	O
combination	O
of	O
output	O
device	O
(	O
called	O
a	O
mode	O
in	O
Metafont	B-Operating_System
)	O
and	O
resolution	O
(	O
visible	O
in	O
the	O
name	O
of	O
the	O
output	O
file	O
,	O
see	O
below	O
)	O
.	O
</s>
<s>
These	O
bitmaps	O
are	O
typically	O
stored	O
for	O
later	O
reuse	O
,	O
so	O
that	O
Metafont	B-Operating_System
does	O
not	O
have	O
to	O
be	O
run	O
every	O
time	O
a	O
document	O
is	O
displayed	O
,	O
but	O
on	O
the	O
other	O
hand	O
TeX	B-Application
distributions	O
with	O
a	O
Metafont	B-Operating_System
component	O
have	O
typically	O
not	O
included	O
any	O
prebuilt	O
bitmap	O
fonts	O
,	O
since	O
they	O
would	O
be	O
rather	O
large	O
in	O
comparison	O
to	O
the	O
sources	O
from	O
which	O
they	O
could	O
be	O
generated	O
.	O
</s>
<s>
Since	O
Metafont	B-Operating_System
fonts	O
were	O
traditionally	O
the	O
TeX	B-Application
default	O
from	O
which	O
other	O
font	O
formats	O
were	O
exceptions	O
,	O
an	O
incomplete	O
installation	O
of	O
a	O
non-Metafont	O
font	O
can	O
sometimes	O
result	O
in	O
Metafont	B-Operating_System
being	O
called	O
and	O
emitting	O
a	O
confusing	O
"	O
somefont.mf	O
not	O
found	O
"	O
error	O
message	O
.	O
</s>
<s>
Equally	O
important	O
,	O
but	O
not	O
as	O
common	O
,	O
is	O
running	O
Metafont	B-Operating_System
to	O
generate	O
a	O
font	O
metric	O
(	O
TFM	O
)	O
file	O
;	O
a	O
TFM	O
file	O
is	O
only	O
generated	O
if	O
the	O
fontmaking	O
variable	O
is	O
positive	O
.	O
</s>
<s>
Traditionally	O
TeX	B-Application
distributions	O
have	O
often	O
come	O
with	O
all	O
TFM	O
files	O
pregenerated	O
(	O
since	O
they	O
are	O
pretty	O
small	O
)	O
,	O
but	O
someone	O
installing	O
a	O
Metafont	B-Operating_System
font	O
from	O
sources	O
will	O
have	O
to	O
generate	O
its	O
TFM	O
file	O
before	O
TeX	B-Application
can	O
use	O
it	O
.	O
</s>
<s>
A	O
third	O
way	O
of	O
operating	O
Metafont	B-Operating_System
is	O
proof	O
mode	O
:	O
if	O
the	O
proofing	O
variable	O
is	O
positive	O
then	O
the	O
bitmap	O
font	O
file	O
also	O
contains	O
additional	O
information	O
provided	O
via	O
special	O
commands	O
,	O
in	O
particular	O
the	O
positions	O
and	O
names	O
of	O
points	O
the	O
font	O
designer	O
considered	O
important	O
for	O
the	O
design	O
.	O
</s>
<s>
If	O
using	O
the	O
separate	O
gftodvi	O
utility	O
to	O
generate	O
enlarged	O
images	O
of	O
the	O
font	O
glyphs	B-Application
,	O
this	O
information	O
from	O
specials	O
is	O
included	O
;	O
point	O
positions	O
are	O
not	O
limited	O
to	O
pixel	O
resolution	O
.	O
</s>
<s>
Metafont	B-Operating_System
can	O
also	O
be	O
run	O
interactively	O
,	O
and	O
has	O
commands	O
for	O
displaying	O
on	O
the	O
screen	O
the	O
images	O
it	O
produces	O
.	O
</s>
<s>
Knuth	O
has	O
said	O
that	O
he	O
uses	O
Metafont	B-Operating_System
as	O
a	O
kind	O
of	O
desk	O
calculator	O
for	O
solving	O
complicated	O
equations	O
,	O
though	O
he	O
now	O
uses	O
MetaPost	B-Language
for	O
mathematical	O
illustrations	O
.	O
</s>
<s>
Metafont	B-Operating_System
can	O
render	O
any	O
kind	O
of	O
graphical	O
output	O
,	O
not	O
just	O
glyphs	B-Application
.	O
</s>
<s>
However	O
,	O
MetaPost	B-Language
and	O
Asymptote	B-Language
are	O
preferred	O
for	O
mathematical	O
illustrations	O
.	O
</s>
<s>
Metafont	B-Operating_System
is	O
most	O
commonly	O
invoked	O
without	O
a	O
direct	O
request	O
from	O
the	O
user	O
.	O
</s>
<s>
DVI	B-Application
files	I-Application
can	O
only	O
contain	O
references	O
to	O
typefaces	O
,	O
rather	O
than	O
the	O
sets	O
of	O
raster	O
or	O
vector	O
glyphs	B-Application
that	O
other	O
formats	O
like	O
PostScript	B-Language
allow	O
.	O
</s>
<s>
Consequently	O
,	O
the	O
glyphs	B-Application
in	O
the	O
typefaces	O
need	O
to	O
be	O
accessed	O
whenever	O
a	O
request	O
is	O
made	O
to	O
view	O
,	O
print	O
or	O
convert	O
a	O
DVI	B-Application
file	O
.	O
</s>
<s>
Metafont	B-Operating_System
outputs	O
several	O
kinds	O
of	O
files	O
:	O
for	O
a	O
file	O
called	O
NAME.mf	O
,	O
it	O
can	O
output	O
:	O
</s>
<s>
NAME.tfm	O
–	O
File	O
with	O
TeX	B-Application
font	O
metric	O
information	O
,	O
which	O
is	O
the	O
information	O
TeX	B-Application
needs	O
.	O
</s>
<s>
Usually	O
metafont	B-Operating_System
has	O
to	O
be	O
told	O
to	O
generate	O
this	O
file	O
.	O
</s>
<s>
After	O
running	O
Metafont	B-Operating_System
,	O
typically	O
one	O
uses	O
the	O
gftopk	O
program	O
to	O
convert	O
the	O
NNNNgf	O
files	O
to	O
pk	O
(	O
packed	O
)	O
format	O
(	O
.NNNNpk	O
)	O
.	O
</s>
<s>
The	O
pk	O
format	O
was	O
primarily	O
introduced	O
to	O
reduce	O
file	O
size	O
(	O
to	O
about	O
half	O
)	O
,	O
but	O
expected	O
to	O
also	O
speed	O
up	O
processing	O
since	O
less	O
data	O
would	O
have	O
to	O
be	O
input/output	B-General_Concept
.	O
</s>
<s>
The	O
GF	O
and	O
PK	O
formats	O
both	O
employ	O
run-length	B-Algorithm
encoding	I-Algorithm
of	O
bitmaps	O
,	O
but	O
make	O
different	O
binary	O
encodings	O
of	O
the	O
run-lengths	B-Algorithm
.	O
</s>
<s>
In	O
the	O
TeX	B-Application
Directory	O
Structure	O
standard	O
,	O
filenames	O
are	O
limited	O
to	O
8+3	O
characters	O
,	O
so	O
GF	O
and	O
PK	O
files	O
would	O
only	O
have	O
extensions	O
.gf	O
and	O
.pk	O
.	O
</s>
<s>
The	O
Metafont	B-Operating_System
language	O
is	O
an	O
interpreted	B-Application
language	I-Application
for	O
programs	O
that	O
are	O
essentially	O
declarative	B-Language
rather	O
than	O
imperative	B-Application
.	O
</s>
<s>
Variables	O
in	O
Metafont	B-Operating_System
can	O
be	O
of	O
eight	O
different	O
types	O
:	O
</s>
<s>
Numeric	O
:	O
fixed-point	O
signed	O
numbers	O
with	O
an	O
epsilon	B-Algorithm
of	O
,	O
capped	O
to	O
be	O
less	O
than	O
4096	O
(	O
Q12.16	B-Algorithm
)	O
.	O
</s>
<s>
Path	O
:	O
as	O
in	O
PostScript/PDF/SVG	O
,	O
a	O
parametric	O
curve	O
in	O
the	O
plane	O
whose	O
coordinate	O
functions	O
are	O
piecewise	B-Algorithm
cubic	O
polynomials	O
.	O
</s>
<s>
Transform	O
:	O
an	O
affine	B-Algorithm
transformation	I-Algorithm
of	O
the	O
plane	O
,	O
equivalent	O
to	O
a	O
"	O
(	O
transformation	O
)	O
matrix	O
"	O
in	O
PostScript/PDF	O
.	O
</s>
<s>
Picture	O
:	O
a	O
raster	B-Algorithm
image	I-Algorithm
with	O
a	O
signed	O
integer	O
value	O
for	O
each	O
pixel	O
.	O
</s>
<s>
Metapost	B-Language
adds	O
color	O
(	O
a	O
triple	O
of	O
numerics	O
)	O
as	O
a	O
ninth	O
type	O
and	O
has	O
a	O
completely	O
different	O
(	O
non-raster	O
)	O
model	O
for	O
pictures	O
;	O
the	O
latter	O
is	O
the	O
main	O
point	O
of	O
divergence	O
between	O
the	O
two	O
programs	O
.	O
</s>
<s>
Metafont	B-Operating_System
vardef	O
macros	O
also	O
live	O
in	O
the	O
same	O
namespace	O
as	O
variables	O
and	O
may	O
in	O
some	O
ways	O
be	O
regarded	O
as	O
a	O
ninth	O
type	O
of	O
variable	O
,	O
although	O
macros	O
do	O
not	O
exist	O
as	O
first-class	O
values	O
in	O
Metafont	B-Operating_System
.	O
</s>
<s>
A	O
very	O
distinctive	O
feature	O
of	O
Metafont	B-Operating_System
is	O
the	O
use	O
of	O
equations	O
to	O
define	O
variables	O
.	O
</s>
<s>
When	O
Metafont	B-Operating_System
executes	O
an	O
equation	O
statement	O
,	O
it	O
turns	O
one	O
of	O
the	O
independents	O
involved	O
into	O
a	O
dependent	O
and	O
eliminates	O
it	O
from	O
the	O
expressions	O
for	O
all	O
other	O
dependents	O
;	O
when	O
no	O
independents	O
remain	O
in	O
the	O
expression	O
for	O
a	O
dependent	O
variable	O
,	O
that	O
variable	O
becomes	O
known	O
.	O
</s>
<s>
Solving	O
linear	O
equation	O
systems	O
thus	O
is	O
a	O
built-in	O
feature	O
of	O
the	O
Metafont	B-Operating_System
language	O
,	O
and	O
the	O
recommended	O
method	O
of	O
assigning	O
most	O
variables	O
(	O
especially	O
those	O
whose	O
values	O
have	O
geometric	O
significance	O
)	O
is	O
to	O
state	O
equations	O
determining	O
their	O
values	O
.	O
</s>
<s>
They	O
have	O
a	O
more	O
direct	O
internal	O
representation	O
than	O
ordinary	O
variables	O
,	O
making	O
it	O
convenient	O
for	O
primitive	O
operations	O
in	O
Metafont	B-Operating_System
(	O
or	O
extensions	O
thereof	O
)	O
to	O
use	O
them	O
implicitly	O
.	O
</s>
<s>
Metafont	B-Operating_System
has	O
numeric	O
and	O
string	O
constant	O
tokens	O
with	O
mainstream	O
syntaxes	O
;	O
strings	O
are	O
delimited	O
by	O
"	O
quotes	O
,	O
numeric	O
constants	O
can	O
have	O
decimals	O
but	O
not	O
an	O
exponent	O
part	O
.	O
</s>
<s>
Except	O
where	O
characters	O
are	O
involved	O
in	O
numeric	O
or	O
string	O
constants	O
,	O
the	O
extent	O
of	O
the	O
token	O
containing	O
a	O
particular	O
character	O
depends	O
on	O
to	O
which	O
class	O
the	O
character	O
belongs	O
;	O
unlike	O
TeX	B-Application
,	O
Metafont	B-Operating_System
has	O
fixed	O
character	O
classes	O
.	O
</s>
<s>
A	O
notable	O
application	O
of	O
these	O
rules	O
is	O
that	O
#	O
is	O
frequently	O
appearing	O
as	O
part	O
of	O
variable	O
names	O
in	O
Metafont	B-Operating_System
code	O
,	O
e.g.	O
</s>
<s>
Delimiters	O
(	O
such	O
as	O
parentheses	O
)	O
do	O
not	O
have	O
built-in	O
meanings	O
,	O
instead	O
there	O
is	O
a	O
command	O
that	O
turns	O
two	O
symbolic	O
tokens	O
into	O
a	O
pair	O
of	O
matching	O
delimiters	O
,	O
but	O
normally	O
Metafont	B-Operating_System
programs	O
use	O
only	O
the	O
ordinary	O
parentheses	O
.	O
</s>
<s>
Curves	O
in	O
Metafont	B-Operating_System
are	O
defined	O
as	O
cubic	B-Algorithm
splines	I-Algorithm
rather	O
than	O
quadratic	O
,	O
for	O
greater	O
versatility	O
at	O
the	O
cost	O
of	O
more	O
complex	O
arithmetic	O
.	O
</s>
<s>
Unlike	O
more	O
common	O
outline	O
font	O
formats	O
(	O
such	O
as	O
TrueType	O
or	O
PostScript	B-Language
Type	O
1	O
)	O
,	O
a	O
Metafont	B-Operating_System
font	O
is	O
primarily	O
made	O
up	O
of	O
strokes	O
with	O
finite-width	O
"	O
pens	O
"	O
,	O
along	O
with	O
filled	O
regions	O
.	O
</s>
<s>
Thus	O
,	O
rather	O
than	O
describing	O
the	O
outline	O
of	O
the	O
glyph	B-Application
directly	O
,	O
a	O
Metafont	B-Operating_System
file	O
describes	O
the	O
pen	O
paths	O
.	O
</s>
<s>
Some	O
simpler	O
Metafont	B-Operating_System
fonts	O
,	O
such	O
as	O
the	O
calligraphic	O
mathematics	O
fonts	O
in	O
the	O
Computer	O
Modern	O
family	O
,	O
use	O
a	O
single	O
pen	O
stroke	O
with	O
a	O
relatively	O
large	O
pen	O
to	O
define	O
each	O
visual	O
"	O
stroke	O
"	O
of	O
the	O
glyphs	B-Application
.	O
</s>
<s>
Since	O
the	O
font	O
shapes	O
are	O
defined	O
by	O
equations	O
rather	O
than	O
directly	O
coded	O
numbers	O
,	O
it	O
is	O
possible	O
to	O
treat	O
parameters	O
such	O
as	O
aspect	O
ratio	O
,	O
font	O
slant	O
,	O
stroke	O
width	O
,	O
serif	O
size	O
,	O
and	O
so	O
forth	O
as	O
input	O
parameters	O
in	O
each	O
glyph	B-Application
definition	O
(	O
which	O
then	O
define	O
not	O
a	O
single	O
font	O
,	O
but	O
a	O
meta-font	O
)	O
.	O
</s>
<s>
Thus	O
,	O
by	O
changing	O
the	O
value	O
of	O
one	O
of	O
these	O
parameters	O
at	O
one	O
location	O
in	O
the	O
Metafont	B-Operating_System
file	O
,	O
one	O
can	O
produce	O
a	O
consistent	O
change	O
throughout	O
the	O
entire	O
font	O
.	O
</s>
<s>
Computer	O
Modern	O
Roman	O
illustrates	O
many	O
uses	O
of	O
this	O
feature	O
;	O
a	O
typical	O
TeX	B-Application
installation	O
includes	O
a	O
number	O
of	O
versions	O
of	O
the	O
font	O
in	O
pitches	O
from	O
5	O
to	O
17	O
cpi	O
,	O
with	O
the	O
stroke	O
widths	O
the	O
same	O
in	O
all	O
sizes	O
(	O
rather	O
than	O
increasing	O
as	O
the	O
font	O
is	O
scaled	O
up	O
)	O
.	O
</s>
<s>
In	O
addition	O
,	O
the	O
Computer	O
Modern	O
typewriter	O
and	O
sans-serif	O
fonts	O
are	O
defined	O
using	O
essentially	O
the	O
same	O
Metafont	B-Operating_System
file	O
as	O
the	O
Roman	O
font	O
,	O
but	O
with	O
different	O
global	O
parameters	O
.	O
</s>
<s>
While	O
well-known	O
type	O
designers	O
,	O
such	O
as	O
Hermann	O
Zapf	O
,	O
have	O
collaborated	O
with	O
Knuth	O
to	O
create	O
new	O
fonts	O
using	O
Metafont	B-Operating_System
,	O
the	O
system	O
has	O
not	O
been	O
widely	O
adopted	O
by	O
professional	O
type	O
designers	O
.	O
</s>
<s>
Available	O
online	O
at	O
</ref>	O
Jonathan	O
Hoefler	O
commented	O
that	O
the	O
Metafont	B-Operating_System
system	O
ultimately	O
became	O
"	O
a	O
technology	O
behind	O
zero	O
of	O
your	O
favourite	O
fonts	O
...	O
Knuth	O
'	O
s	O
idea	O
that	O
letters	O
start	O
with	O
skeletal	O
forms	O
is	O
flawed.	O
"	O
</s>
<s>
The	O
Metafont	B-Operating_System
system	O
allows	O
fonts	O
to	O
be	O
processed	O
in	O
unusual	O
ways	O
;	O
in	O
1982	O
Knuth	O
showed	O
how	O
it	O
could	O
be	O
used	O
to	O
morph	O
fonts	O
,	O
with	O
a	O
serif	O
font	O
slowly	O
transitioning	O
into	O
a	O
sans-serif	O
design	O
over	O
the	O
course	O
of	O
a	O
text	O
.	O
</s>
<s>
Donald	O
Knuth	O
started	O
work	O
on	O
font	O
creation	O
software	O
in	O
1977	O
,	O
and	O
produced	O
the	O
first	O
version	O
of	O
Metafont	B-Operating_System
in	O
1979	O
.	O
</s>
<s>
Due	O
to	O
shortcomings	O
in	O
the	O
original	O
Metafont	B-Operating_System
language	O
,	O
Knuth	O
developed	O
an	O
entirely	O
new	O
Metafont	B-Operating_System
system	O
in	O
1984	O
,	O
and	O
it	O
is	O
this	O
revised	O
system	O
that	O
is	O
used	O
today	O
;	O
Metafont	B-Operating_System
has	O
a	O
versioning	O
system	O
similar	O
to	O
that	O
of	O
TeX	B-Application
,	O
where	O
the	O
number	O
asymptotically	O
approaches	O
e	O
with	O
each	O
revision	O
.	O
</s>
<s>
This	O
yields	O
the	O
following	O
glyph	B-Application
:	O
</s>
<s>
Then	O
it	O
can	O
be	O
used	O
in	O
a	O
LaTeX	O
file	O
such	O
as	O
(	O
all	O
files	O
should	O
dwell	O
in	O
the	O
same	O
directory	O
or	O
the	O
TeX	B-Application
system	O
should	O
be	O
informed	O
about	O
them	O
using	O
appropriate	O
methods	O
)	O
:	O
</s>
<s>
The	O
resulting	O
PDF	B-Application
file	I-Application
should	O
look	O
like	O
this	O
:	O
</s>
<s>
There	O
are	O
several	O
tools	O
for	O
converting	O
Metafont	B-Operating_System
programs	O
to	O
PostScript	B-Language
Type	O
1	O
fonts	O
.	O
</s>
<s>
Most	O
make	O
use	O
of	O
MetaPost	B-Language
's	O
ability	O
to	O
convert	O
a	O
subset	O
of	O
Metafont	B-Operating_System
's	O
language	O
into	O
EPS	B-Language
outlines	O
,	O
which	O
can	O
subsequently	O
be	O
converted	O
to	O
PostScript	B-Language
Type	O
1	O
fonts	O
.	O
</s>
<s>
Generating	O
vector	O
outlines	O
of	O
Metafont	B-Operating_System
pen	O
strokes	O
is	O
nontrivial	O
,	O
as	O
the	O
Metafont	B-Operating_System
model	O
of	O
a	O
glyph	B-Application
is	O
a	O
raster	B-Algorithm
image	I-Algorithm
and	O
the	O
exact	O
outlines	O
of	O
most	O
strokes	O
are	O
not	O
Bézier	O
curves	O
.	O
</s>
<s>
The	O
Polish	O
JNS	O
team	O
developed	O
METATYPE1	B-General_Concept
(	O
based	O
on	O
MetaPost	B-Language
)	O
for	O
creating	O
PostScript	B-Language
Type	O
1	O
fonts	O
.	O
</s>
<s>
Its	O
big	O
disadvantage	O
is	O
that	O
no	O
pens	O
may	O
be	O
used	O
which	O
highly	O
reduces	O
the	O
power	O
of	O
Metafont	B-Operating_System
language	O
.	O
</s>
<s>
Initially	O
,	O
tool	O
has	O
been	O
used	O
by	O
the	O
Polish	O
GUST	B-Application
typeface	O
foundry	O
to	O
produce	O
a	O
modernized	O
and	O
extended	O
variant	O
of	O
Computer	O
Modern	O
,	O
called	O
Latin	O
Modern	O
.	O
</s>
<s>
mf2pt1	O
,	O
which	O
is	O
also	O
based	O
on	O
Metapost	B-Language
,	O
was	O
developed	O
by	O
Scott	O
Pakin	O
with	O
some	O
contributions	O
from	O
Werner	O
Lemberg	O
.	O
</s>
<s>
It	O
also	O
has	O
several	O
limitations	O
detailed	O
in	O
its	O
manual	O
,	O
the	O
most	O
significant	O
one	O
being	O
the	O
restriction	O
that	O
each	O
glyph	B-Application
must	O
be	O
drawn	O
entirely	O
from	O
closed	O
paths	O
.	O
</s>
<s>
In	O
order	O
to	O
overcome	O
the	O
limitations	O
of	O
mf2pt1	O
,	O
the	O
EPS	B-Language
output	O
by	O
Metapost	B-Language
can	O
be	O
post-processed	O
with	O
FontForge	B-Application
,	O
which	O
is	O
capable	O
of	O
interpreting	O
complex	O
PostScript	B-Language
paths	O
generated	O
by	O
Metapost	B-Language
from	O
Metafont	B-Operating_System
's	O
elliptic	O
pens	O
,	O
and	O
also	O
capable	O
of	O
removing	O
contour	O
overlaps	O
.	O
</s>
<s>
Since	O
FontForge	B-Application
supports	O
scripting	O
,	O
this	O
post-processing	O
step	O
can	O
also	O
be	O
automated	O
.	O
</s>
<s>
It	O
can	O
process	O
only	O
Metapost	B-Language
output.K.	O
</s>
<s>
The	O
common	O
approach	O
to	O
generate	O
Type	O
1	O
fonts	O
with	O
pen	O
strokes	O
remains	O
to	O
generate	O
a	O
high-resolution	O
bitmap	O
and	O
then	O
using	O
an	O
autotracer	O
,	O
implemented	O
by	O
packages	O
such	O
as	O
mftracemftrace	O
–	O
a	O
small	O
Python	O
program	O
that	O
lets	O
you	O
trace	O
a	O
TeX	B-Application
bitmap	O
font	O
into	O
a	O
PFA	O
or	O
PFB	O
font	O
(	O
A	O
PostScript	B-Language
Type1	O
Scalable	O
Font	O
)	O
or	O
TTF	O
(	O
TrueType	O
)	O
font	O
.	O
</s>
<s>
and	O
TeXtraceTeXtrace	O
–	O
a	O
collection	O
of	O
scripts	O
for	O
UNIX	O
that	O
convert	O
any	O
TeX	B-Application
font	O
into	O
a	O
Type1	O
.pfb	O
outline	O
font	O
immediately	O
suitable	O
for	O
use	O
with	O
dvips	O
,	O
pdftex	O
,	O
acroread	O
(	O
and	O
any	O
many	O
other	O
programs	O
)	O
.	O
</s>
<s>
Donald	O
Knuth	O
:	O
Metafont	B-Operating_System
:	O
The	O
Program	O
,	O
Addison-Wesley	O
1986	O
.	O
</s>
<s>
The	O
source	O
code	O
of	O
the	O
book	O
in	O
TeX	B-Application
(	O
and	O
a	O
needed	O
macro	O
)	O
is	O
available	O
online	O
on	O
CTAN	B-General_Concept
.	O
</s>
<s>
Donald	O
Knuth	O
:	O
The	O
Metafont	B-Operating_System
source	O
code	O
is	O
written	O
in	O
the	O
WEB	O
programming	O
language	O
,	O
and	O
includes	O
very	O
extensive	O
documentation	O
about	O
the	O
algorithms	O
used	O
in	O
Metafont	B-Operating_System
.	O
</s>
<s>
K	O
.	O
Píška	O
,	O
"	O
Creating	O
Type	O
1	O
fonts	O
from	O
Metafont	B-Operating_System
sources	O
:	O
comparison	O
of	O
tools	O
,	O
techniques	O
and	O
results	O
"	O
,	O
in	O
TeX	B-Application
,	O
XML	O
,	O
and	O
Digital	O
Typography	O
(	O
Springer-Verlag	O
,	O
Berlin	O
,	O
2004	O
)	O
,	O
Lect	O
.	O
</s>
<s>
Hofstadter	O
,	O
Douglas	O
R.	O
,	O
"	O
Metafont	B-Operating_System
,	O
Metamathematics	O
,	O
and	O
Metaphysics	O
:	O
Comments	O
on	O
Donald	O
Knuth	O
's	O
Article	O
'	O
The	O
Concept	O
of	O
a	O
Meta-Font	O
'	O
 "	O
Visible	O
Language	O
,	O
Vol	O
.	O
</s>
