<s>
The	O
computer	B-Application
program	I-Application
pdfTeX	B-Language
is	O
an	O
extension	O
of	O
Knuth	O
's	O
typesetting	O
program	O
TeX	B-Application
,	O
and	O
was	O
originally	O
written	O
and	O
developed	O
into	O
a	O
publicly	O
usable	O
product	O
by	O
Hàn	B-Language
Thế	I-Language
Thành	I-Language
as	O
a	O
part	O
of	O
the	O
work	O
for	O
his	O
PhD	O
thesis	O
at	O
the	O
Faculty	O
of	O
Informatics	O
,	O
Masaryk	O
University	O
,	O
Brno	O
,	O
Czech	O
Republic	O
.	O
</s>
<s>
The	O
idea	O
of	O
making	O
this	O
extension	O
to	O
TeX	B-Application
was	O
conceived	O
during	O
the	O
early	O
1990s	O
,	O
when	O
Jiří	O
Zlatuška	O
and	O
Phil	O
Taylor	O
discussed	O
some	O
developmental	O
ideas	O
with	O
Donald	O
Knuth	O
at	O
Stanford	O
University	O
.	O
</s>
<s>
Knuth	O
later	O
met	O
Hàn	B-Language
Thế	I-Language
Thành	I-Language
in	O
Brno	O
during	O
his	O
visit	O
to	O
the	O
Faculty	O
of	O
Informatics	O
to	O
receive	O
an	O
honorary	O
doctorate	O
from	O
Masaryk	O
University	O
.	O
</s>
<s>
Two	O
prominent	O
characteristics	O
of	O
pdfTeX	B-Language
are	O
character	O
protrusion	O
,	O
which	O
generalizes	O
the	O
concept	O
of	O
hanging	O
punctuation	O
,	O
and	O
font	O
expansion	O
,	O
an	O
implementation	O
of	O
Hermann	O
Zapf	O
's	O
ideas	O
for	O
improving	O
the	O
grayness	O
of	O
a	O
typeset	O
page	O
.	O
</s>
<s>
pdfTeX	B-Language
is	O
included	O
in	O
most	O
modern	O
distributions	O
of	O
LaTeX	B-Application
and	O
ConTeXt	O
(	O
including	O
TeX	B-General_Concept
Live	I-General_Concept
,	O
MacTeX	B-General_Concept
,	O
and	O
MiKTeX	B-General_Concept
)	O
and	O
used	O
as	O
the	O
default	O
TeX	B-Application
engine	O
.	O
</s>
<s>
The	O
main	O
difference	O
between	O
TeX	B-Application
and	O
pdfTeX	B-Language
is	O
that	O
whereas	O
TeX	B-Application
outputs	O
DVI	O
files	O
,	O
pdfTeX	B-Language
can	O
output	O
PDF	B-Application
files	I-Application
directly	O
.	O
</s>
<s>
This	O
allows	O
tight	O
integration	O
of	O
PDF	B-Application
features	O
such	O
as	O
hypertext	O
links	O
and	O
tables	O
of	O
contents	O
,	O
using	O
packages	O
such	O
as	O
hyperref	O
.	O
</s>
<s>
On	O
the	O
other	O
hand	O
,	O
packages	O
(	O
such	O
as	O
PSTricks	B-Language
)	O
which	O
exploit	O
the	O
earlier	O
conversion	O
process	O
of	O
DVI-to-PostScript	O
may	O
fail	O
,	O
although	O
replacements	O
such	O
as	O
PGF/TikZ	B-Operating_System
have	O
been	O
written	O
.	O
</s>
<s>
Direct	O
embedding	O
of	O
PostScript	B-Language
graphics	O
is	O
no	O
longer	O
functional	O
,	O
and	O
one	O
has	O
to	O
use	O
a	O
program	O
such	O
as	O
eps2pdf	O
to	O
convert	O
EPS	O
files	O
to	O
PDF	B-Application
,	O
which	O
can	O
then	O
be	O
directly	O
inserted	O
by	O
pdfTeX	B-Language
.	O
</s>
<s>
It	O
is	O
possible	O
to	O
obtain	O
DVI	O
output	O
from	O
pdfTeX	B-Language
.	O
</s>
<s>
This	O
DVI	O
output	O
should	O
be	O
identical	O
to	O
that	O
of	O
TeX	B-Application
,	O
unless	O
pdfTeX	B-Language
's	O
extra	O
microtypography	O
features	O
have	O
been	O
activated	O
.	O
</s>
<s>
Moreover	O
,	O
since	O
LaTeX	B-Application
,	O
ConTeXt	O
et	O
al	O
.	O
</s>
<s>
are	O
simply	O
macro	O
packages	O
for	O
TeX	B-Application
,	O
they	O
work	O
equally	O
well	O
with	O
pdfTeX	B-Language
.	O
</s>
<s>
Hence	O
,	O
pdflatex	B-Language
,	O
for	O
example	O
,	O
calls	O
the	O
pdfTeX	B-Language
program	O
using	O
the	O
standard	O
LaTeX	B-Application
macros	O
to	O
typeset	O
LaTeX	B-Application
documents	O
,	O
whereas	O
it	O
is	O
the	O
default	O
rendering	O
engine	O
for	O
ConTeXt	O
documents	O
.	O
</s>
<s>
pdfTeX	B-Language
has	O
several	O
features	O
not	O
available	O
in	O
standard	O
TeX	B-Application
:	O
</s>
