[Fontconfig] high dpi displays

[Eric Rannaud]

On Fri, Apr 20, 2012 at 4:39 PM, Chris Jones <cjns1989 at gmail.com> wrote:
> On Fri, Apr 20, 2012 at 06:13:10PM EDT, Alan Coopersmith wrote:
>> On 04/20/12 03:06 PM, Chris Jones wrote:
>
>> > OT.. but where do you get a 200 dpi display..? My personal dream btw
>> > would be a 17-19" 300 dpi... at least for the time being ;-)
>
>> https://www.apple.com/ipad/
>
>> Though http://en.wikipedia.org/wiki/List_of_displays_by_pixel_density
>> has a number of other devices, including some notebooks and
>> traditional LCD monitors in the range as well, such as
>
>> http://en.wikipedia.org/wiki/IBM_T220/T221_LCD_monitors
>
> Yeah.. or smartphones... maybe I should check my coffee maker & my
> dishwasher..?
>
> I meant for _computers_ :-)
>
> Just kiddin' and thanks much for the links.. the issue being I guess
> that not many GPUs can handle 200+ ppi's on screens bigger than 10"..

Modern GPUs could in principle do that just fine... That have had
enough memory to accommodate huge frame buffers for a long time.


> Sorry for the OT, but it's been many years I wished something like the
> lower end of print quality, say 300 ppi.. were available for computer
> displays. Instead you go to Best Buy and you get to pay lots more for
> a heavier bigger hungrier appliance.. with a lower ppi..! Go figure.

Actually, for a bit of history, Windows Longhorn/Vista was supposed to
jumpstart a revolution in screen resolution. Microsoft reworked the
whole graphic stack (including font rendering) to make it a lot more
resolution independent. They were aiming for desktop monitors with at
least 3200x2000 pixels. See this 2004 story on Slashdot
(http://tech.slashdot.org/story/04/07/30/238200/longhorns-windows-graphics-foundation-examined).

It never happened, and it was for a number of reasons:
1- Many, many Windows applications assume about 72 ppi and render
unscaled bitmaps to the screen. All those 16x16 icons? Totally
unusable at 300ppi. A lot of these apps also render text at a fixed
pixel size that is way too small for that kind of resolution. On
Windows 7, you still find a lot of legacy apps rendering horrible
bitmap fonts in random places. There is a lot of apps rendering more
or less directly, and it's hard for Windows to catch these and rescale
on-the-fly. Microsoft didn't really have a strategy to address
resolution-independence for legacy apps, from what I could tell.
2- Vista was very late, and it brought a lot of uncertainty. This
meant that all the work rewriting apps never happened.
3- The hardware seemed to have been behind the curve as well.

My guess is that the software situation made hardware manufacturers
uninterested in pushing the resolution up. Manufacturing was difficult
anyway, but you would have had trouble selling the resulting screens
(at least in volumes sufficient to justify the huge investment needed
across the whole panel industry). That's what happens when people
loose faith in a Moore's law (i.e. a self-fulfilling prophecy of
constant improvement of technology that only works if all market
participants continuously believe in it and invest accordingly).

At the same time, game consoles started dominating game development,
and it didn't really make sense to render games at a much higher
resolution than what they were increasingly being developed for (720p
or even less for most console games, still to this day).

It's interesting to compare that episode with the current software
situation on Android/iOS/Metro. The HTML rendering model has taken the
lead with builtin resolution-independence (automatic reflow, relative
font-sizes, ex/em units), to some extent, and that's the model now
adopted by Android (after a bit of a false start) and Metro (I
think?). Apple sticks with a fixed-resolution model for iOS, using a
simple re-scaling factor to work with a small number of screen sizes.

Desktop monitors have had the exact same resolution for about 5 years
now, while display technology has improved a lot: I bet the situation
would have been very different if Windows had supported
resolution-independence from the beginning.