Re: Debian with HiDPI / 4K displays
On 09/08/15 17:02, Vincent Bernat wrote:
> While it is possible to derive the true DPI setting from the resolution
> and the dimension
... except for when the stated dimensions in the display's EDID are full
of lies and claim that it is 4cm x 3cm, or 16cm x 9cm, or even 0cm x
0cm. See also
<https://lists.fedoraproject.org/pipermail/devel/2011-October/157760.html>
and its surrounding thread - admittedly that was a few years ago. I'd be
delighted to be proved wrong, but I suspect hardware manufacturers
haven't got a whole lot better at this since then.
As has been noted elsewhere in this thread, there are actually two
values that desktop environments are trying to use: taking GNOME as an
example because that's the one I know best, it will happily scale fonts
to any "dpi" value of your choice (even if it isn't an integer multiple
of 96), because fonts are designed to be scalable anyway; but it will
only apply integer numbers of real pixels per "density-independent
pixel", because non-integer ratios there would make all the widgets,
window decoration, icons, etc. blurry, and I think there are some more
technical reasons to prefer integer ratios. Qt 5 similarly only supports
integer numbers of real pixels per dp.
I believe Android supports arbitrary multiples of 0.5 real pixels per
dp, although I don't know how commonly-used those are in practice.
Density-independent pixels (dp) are the Android term; I don't know
whether there's a different conventional name is elsewhere. "CSS pixels"
are basically the same thing as Android's dp.
S
Reply to: