<s>
Resolution	B-General_Concept
independence	I-General_Concept
is	O
where	O
elements	O
on	O
a	O
computer	B-Device
screen	I-Device
are	O
rendered	O
at	O
sizes	O
independent	O
from	O
the	O
pixel	B-Algorithm
grid	I-Algorithm
,	O
resulting	O
in	O
a	O
graphical	B-Application
user	I-Application
interface	I-Application
that	O
is	O
displayed	O
at	O
a	O
consistent	O
physical	O
size	O
,	O
regardless	O
of	O
the	O
resolution	O
of	O
the	O
screen	O
.	O
</s>
<s>
As	O
early	O
as	O
1978	O
,	O
the	O
typesetting	O
system	O
TeX	B-Application
due	O
to	O
Donald	O
Knuth	O
introduced	O
resolution	B-General_Concept
independence	I-General_Concept
into	O
the	O
world	O
of	O
computers	O
.	O
</s>
<s>
This	O
pioneering	O
system	O
has	O
a	O
corresponding	O
font	O
system	O
,	O
Metafont	B-Operating_System
,	O
which	O
provides	O
suitable	O
fonts	O
of	O
the	O
same	O
high	O
standards	O
of	O
resolution	B-General_Concept
independence	I-General_Concept
.	O
</s>
<s>
The	O
terminology	O
device	B-Application
independent	I-Application
file	I-Application
format	I-Application
(	O
DVI	B-Application
)	O
is	O
the	O
file	O
format	O
of	O
Donald	O
Knuth	O
's	O
pioneering	O
TeX	B-Application
system	O
.	O
</s>
<s>
Apple	O
included	O
some	O
support	O
for	O
resolution	B-General_Concept
independence	I-General_Concept
in	O
early	O
versions	O
of	O
macOS	B-Application
,	O
which	O
could	O
be	O
demonstrated	O
with	O
the	O
developer	O
tool	O
Quartz	O
Debug	O
that	O
included	O
a	O
feature	O
allowing	O
the	O
user	O
to	O
scale	O
the	O
interface	O
.	O
</s>
<s>
However	O
,	O
the	O
feature	O
was	O
incomplete	O
,	O
as	O
some	O
icons	O
did	O
not	O
show	O
(	O
such	O
as	O
in	O
System	O
Preferences	O
)	O
,	O
user	O
interface	O
elements	O
were	O
displayed	O
at	O
odd	O
positions	O
and	O
certain	O
bitmap	O
GUI	B-Application
elements	O
were	O
not	O
scaled	O
smoothly	O
.	O
</s>
<s>
Because	O
the	O
scaling	O
feature	O
was	O
never	O
completed	O
,	O
macOS	B-Application
's	O
user	O
interface	O
remained	O
resolution-dependent	O
.	O
</s>
<s>
On	O
June	O
11	O
,	O
2012	O
,	O
Apple	O
introduced	O
the	O
2012	O
MacBook	B-Device
Pro	I-Device
with	O
a	O
resolution	O
of	O
2880×1800	O
or	O
5.2	O
megapixels	O
–	O
doubling	O
the	O
pixel	B-Algorithm
density	O
in	O
both	O
dimensions	O
.	O
</s>
<s>
The	O
laptop	O
shipped	O
with	O
a	O
version	O
of	O
macOS	B-Application
that	O
provided	O
support	O
to	O
scale	O
the	O
user	O
interface	O
twice	O
as	O
big	O
as	O
it	O
has	O
previously	O
been	O
.	O
</s>
<s>
This	O
feature	O
is	O
called	O
HighDPI	O
mode	O
in	O
macOS	B-Application
and	O
it	O
uses	O
a	O
fixed	O
scaling	O
factor	O
of	O
2	O
to	O
increase	O
the	O
size	O
of	O
the	O
user	O
interface	O
for	O
high-DPI	O
screens	O
.	O
</s>
<s>
Thus	O
,	O
while	O
the	O
macOS	B-Application
's	O
user	O
interface	O
can	O
be	O
scaled	O
using	O
this	O
approach	O
,	O
the	O
UI	O
itself	O
is	O
not	O
resolution-independent	O
.	O
</s>
<s>
The	O
GDI	B-Operating_System
system	O
in	O
Windows	O
is	O
pixel-based	O
and	O
thus	O
not	O
resolution-independent	O
.	O
</s>
<s>
To	O
scale	O
up	O
the	O
UI	O
,	O
Microsoft	B-Application
Windows	I-Application
has	O
supported	O
specifying	O
a	O
custom	O
DPI	O
from	O
the	O
Control	O
Panel	O
since	O
Windows	B-Application
95	I-Application
.	O
</s>
<s>
(	O
In	O
Windows	B-Application
3.1	I-Application
,	O
the	O
DPI	O
setting	O
is	O
tied	O
to	O
the	O
screen	O
resolution	O
,	O
depending	O
on	O
the	O
driver	O
information	O
file	O
.	O
)	O
</s>
<s>
GDI+	B-Operating_System
in	O
Windows	B-Application
XP	I-Application
adds	O
resolution-independent	O
text	O
rendering	O
however	O
,	O
the	O
UI	O
in	O
Windows	O
versions	O
up	O
to	O
Windows	B-Application
XP	I-Application
is	O
not	O
completely	O
high-DPI	O
aware	O
as	O
displays	O
with	O
very	O
high	O
resolutions	O
and	O
high	O
pixel	B-Algorithm
densities	O
were	O
not	O
available	O
in	O
that	O
time	O
frame	O
.	O
</s>
<s>
Windows	B-Application
Vista	I-Application
and	O
Windows	B-Device
7	I-Device
scale	O
better	O
at	O
higher	O
DPIs	O
.	O
</s>
<s>
Windows	B-Application
Vista	I-Application
also	O
adds	O
support	O
for	O
programs	O
to	O
declare	O
themselves	O
to	O
the	O
OS	O
that	O
they	O
are	O
high-DPI	O
aware	O
via	O
a	O
manifest	O
file	O
or	O
using	O
an	O
API	O
.	O
</s>
<s>
For	O
programs	O
that	O
do	O
not	O
declare	O
themselves	O
as	O
DPI-aware	O
,	O
Windows	B-Application
Vista	I-Application
supports	O
a	O
compatibility	O
feature	O
called	O
DPI	O
virtualization	O
so	O
system	O
metrics	O
and	O
UI	O
elements	O
are	O
presented	O
to	O
applications	O
as	O
if	O
they	O
are	O
running	O
at	O
96	O
DPI	O
and	O
the	O
Desktop	O
Window	O
Manager	O
then	O
scales	O
the	O
resulting	O
application	O
window	O
to	O
match	O
the	O
DPI	O
setting	O
.	O
</s>
<s>
Windows	B-Application
Vista	I-Application
retains	O
the	O
Windows	B-Application
XP	I-Application
style	O
scaling	O
option	O
which	O
when	O
enabled	O
turns	O
off	O
DPI	O
virtualization	O
(	O
blurry	O
text	O
)	O
for	O
all	O
applications	O
globally	O
.	O
</s>
<s>
Windows	B-Application
Vista	I-Application
also	O
introduces	O
Windows	B-Device
Presentation	I-Device
Foundation	I-Device
.	O
</s>
<s>
WPF	O
applications	O
are	O
vector-based	O
,	O
not	O
pixel-based	O
and	O
are	O
designed	O
to	O
be	O
resolution-independent	O
.	O
</s>
<s>
Windows	B-Device
7	I-Device
adds	O
the	O
ability	O
to	O
change	O
the	O
DPI	O
by	O
doing	O
only	O
a	O
log	O
off	O
,	O
not	O
a	O
full	O
reboot	O
and	O
makes	O
it	O
a	O
per-user	O
setting	O
.	O
</s>
<s>
Additionally	O
,	O
Windows	B-Device
7	I-Device
reads	O
the	O
monitor	O
DPI	O
from	O
the	O
EDID	B-General_Concept
and	O
automatically	O
sets	O
the	O
DPI	O
value	O
to	O
match	O
the	O
monitor	O
's	O
physical	O
pixel	B-Algorithm
density	O
,	O
unless	O
the	O
effective	O
resolution	O
is	O
less	O
than	O
1024	O
x	O
768	O
.	O
</s>
<s>
In	O
Windows	B-Application
8	I-Application
,	O
only	O
the	O
DPI	O
scaling	O
percentage	O
is	O
shown	O
in	O
the	O
DPI	O
changing	O
dialog	O
and	O
the	O
display	O
of	O
the	O
raw	O
DPI	O
value	O
has	O
been	O
removed	O
.	O
</s>
<s>
In	O
Windows	B-Device
8.1	I-Device
,	O
the	O
global	O
setting	O
to	O
disable	O
DPI	O
virtualization	O
(	O
only	O
use	O
XP-style	O
scaling	O
)	O
is	O
removed	O
.	O
</s>
<s>
At	O
pixel	B-Algorithm
densities	O
higher	O
than	O
120	O
PPI	O
(	O
125%	O
)	O
,	O
DPI	O
virtualization	O
is	O
enabled	O
for	O
all	O
applications	O
without	O
a	O
DPI	O
aware	O
flag	O
(	O
manifest	O
)	O
set	O
inside	O
the	O
EXE	O
.	O
</s>
<s>
Windows	B-Device
8.1	I-Device
retains	O
a	O
per-application	O
option	O
to	O
disable	O
DPI	O
virtualization	O
of	O
an	O
app	O
.	O
</s>
<s>
Windows	B-Device
8.1	I-Device
also	O
adds	O
the	O
ability	O
for	O
each	O
display	O
to	O
use	O
an	O
independent	O
DPI	O
setting	O
,	O
although	O
it	O
calculates	O
this	O
automatically	O
for	O
each	O
display	O
.	O
</s>
<s>
Windows	B-Device
8.1	I-Device
prevents	O
a	O
user	O
from	O
forcibly	O
enabling	O
DPI	O
virtualization	O
of	O
an	O
application	O
.	O
</s>
<s>
Therefore	O
,	O
if	O
an	O
application	O
wrongly	O
claims	O
to	O
be	O
DPI-aware	O
,	O
it	O
will	O
look	O
too	O
small	O
on	O
high-DPI	O
displays	O
in	O
8.1	B-Device
,	O
and	O
a	O
user	O
cannot	O
correct	O
that	O
.	O
</s>
<s>
Windows	B-Operating_System
10	I-Operating_System
adds	O
manual	O
control	O
over	O
DPI	O
for	O
individual	O
monitors	O
.	O
</s>
<s>
In	O
addition	O
,	O
Windows	B-Operating_System
10	I-Operating_System
version	O
1703	O
brings	O
back	O
the	O
XP-style	O
GDI	B-Operating_System
scaling	O
under	O
a	O
"	O
System	O
(	O
Enhanced	O
)	O
"	O
option	O
.	O
</s>
<s>
This	O
option	O
combines	O
GDI+'s	O
text	O
rendering	O
at	O
a	O
higher	O
resolution	O
with	O
the	O
usual	O
scaling	O
of	O
other	O
elements	O
,	O
so	O
that	O
text	O
appears	O
crisper	O
than	O
in	O
the	O
normal	O
"	O
System	O
"	O
virtualization	O
mode	O
.	O
</s>
<s>
Since	O
Android	B-Application
1.6	I-Application
"	O
Donut	B-Application
"	O
(	O
September	O
2009	O
)	O
Android	B-Application
has	O
provided	O
support	O
for	O
multiple	O
screen	O
sizes	O
and	O
densities	O
.	O
</s>
<s>
Android	B-Application
expresses	O
layout	O
dimensions	O
and	O
position	O
via	O
the	O
density-independent	O
pixel	B-Algorithm
or	O
"	O
dp	O
"	O
which	O
is	O
defined	O
as	O
one	O
physical	O
pixel	B-Algorithm
on	O
a	O
160	O
dpi	O
screen	O
.	O
</s>
<s>
To	O
aid	O
in	O
the	O
creation	O
of	O
underlying	O
bitmaps	O
,	O
Android	B-Application
categorizes	O
resources	O
based	O
on	O
screen	O
size	O
and	O
density	O
:	O
</s>
<s>
The	O
Xft	B-Application
library	O
,	O
the	O
font	O
rendering	O
library	O
for	O
the	O
X11	O
system	O
,	O
has	O
a	O
dpi	O
setting	O
that	O
defaults	O
to	O
75	O
.	O
</s>
<s>
This	O
is	O
simply	O
a	O
wrapper	O
around	O
the	O
FC_DPI	O
system	O
in	O
fontconfig	O
,	O
but	O
it	O
suffices	O
for	O
scaling	O
the	O
text	O
in	O
Xft-based	O
applications	O
.	O
</s>
<s>
The	O
mechanism	O
is	O
also	O
detected	O
by	O
desktop	O
environments	O
to	O
set	O
its	O
own	O
DPI	O
,	O
usually	O
in	O
conjunction	O
with	O
the	O
EDID-based	O
family	O
of	O
Xlib	B-Language
functions	O
.	O
</s>
<s>
The	O
latter	O
has	O
been	O
rendered	O
ineffective	O
in	O
Xorg	O
Server	O
1.7	O
;	O
since	O
then	O
EDID	B-General_Concept
information	O
is	O
only	O
exposed	O
to	O
XRandR	O
.	O
</s>
<s>
In	O
2013	O
,	O
the	O
GNOME	B-Application
desktop	I-Application
environment	I-Application
began	O
efforts	O
to	O
bring	O
resolution	B-General_Concept
independence	I-General_Concept
(	O
"	O
hi-DPI	O
"	O
support	O
)	O
for	O
various	O
parts	O
of	O
the	O
graphics	O
stack	O
.	O
</s>
<s>
Developer	O
Alexander	O
Larsson	O
initially	O
wrote	O
about	O
changes	O
required	O
in	O
GTK+	B-Application
,	O
Cairo	B-Language
,	O
Wayland	B-Language
and	O
the	O
GNOME	B-Application
themes	O
.	O
</s>
<s>
At	O
the	O
end	O
of	O
the	O
BoF	O
sessions	O
at	O
GUADEC	B-Application
2013	O
,	O
GTK+	B-Application
developer	O
Matthias	O
Clasen	O
mentioned	O
that	O
hi-DPI	O
support	O
would	O
be	O
"	O
pretty	O
complete	O
"	O
in	O
GTK	B-Application
3.10	O
once	O
work	O
on	O
Cairo	B-Language
would	O
be	O
completed	O
.	O
</s>
<s>
As	O
of	O
January	O
2014	O
,	O
hi-DPI	O
support	O
for	O
Clutter	B-Language
and	O
GNOME	B-Language
Shell	I-Language
is	O
ongoing	O
work	O
.	O
</s>
<s>
Gtk	B-Application
supports	O
scaling	O
all	O
UI	O
elements	O
by	O
integer	O
factors	O
,	O
and	O
all	O
text	O
by	O
any	O
non-negative	O
real	O
number	O
factors	O
.	O
</s>
<s>
Although	O
not	O
related	O
to	O
true	O
resolution	B-General_Concept
independence	I-General_Concept
,	O
some	O
other	O
operating	O
systems	O
use	O
GUIs	B-Application
that	O
are	O
able	O
to	O
adapt	O
to	O
changed	O
font	O
sizes	O
.	O
</s>
<s>
Microsoft	B-Application
Windows	I-Application
95	I-Application
onwards	O
used	O
the	O
Marlett	O
TrueType	O
font	O
in	O
order	O
to	O
scale	O
some	O
window	O
controls	O
(	O
close	O
,	O
maximize	O
,	O
minimize	O
,	O
resize	O
handles	O
)	O
to	O
arbitrary	O
sizes	O
.	O
</s>
<s>
AmigaOS	B-Application
from	O
version	O
2.04	O
(	O
1991	O
)	O
was	O
able	O
to	O
adapt	O
its	O
window	O
controls	O
to	O
any	O
font	O
size	O
.	O
</s>
<s>
Video	O
games	O
are	O
often	O
resolution-independent	O
;	O
an	O
early	O
example	O
is	O
Another	B-Application
World	I-Application
for	O
DOS	B-Device
,	O
which	O
used	O
polygons	O
to	O
draw	O
its	O
2D	O
content	O
and	O
was	O
later	O
remade	O
using	O
the	O
same	O
polygons	O
at	O
a	O
much	O
higher	O
resolution	O
.	O
</s>
