Why EDID is not trustworthy for DPI

Evandro Giovanini efgiovanini at gmail.com
Thu Oct 6 12:46:19 UTC 2011

Em Qui, 2011-10-06 às 08:21 -0400, Simo Sorce escreveu:
> On Thu, 2011-10-06 at 13:06 +0200, Nicolas Mailhot wrote:
> > Le Mer 5 octobre 2011 21:44, Simo Sorce a écrit :
> > 
> > > Are you saying fonts should change on the fly when I move an app between
> > > 2 monitors that have different DPIs ?
> > 
> > Unfortunately, when you get into situations with more than 150% difference in
> > pixel densities between displays (as we've been creeping towards in the last
> > decade) that's the only way to display text the user will be able to read.
> > 
> > You can check it now easily, just get a run-of-the-mill full-hd 15" laptop
> > (not even a tiny netbook), a run-of-the-mill 22" or more screen (nothing
> > especially uncommon either), create an extended desktop with both screens and
> > try to set a satisfying font size. I defy you to find a setting that won't
> > look way too small or way too big on one of the screens. And it won't matter
> > if the user likes small or big fonts.
> Nicolas I am aware of the issue, but I am also aware of the technical
> difficulties in doing something like that.
> It's not possible today and I am not sure it will be in the near future.
> So currently the only option is to tell the user that we do not support
> multiple displays where pixel density varies by moire than 10% between
> them.
> I would even go as far as saying that by default gnome should refuse to
> let you join together screens of so high difference in density except we
> cannot trust the HW info apparently, so all we are left with is a bad
> user experience.

Please don't. I extend my 11" laptop on a 32" TV and despite poor
readability of regular fonts it still works just fine for what I need -
movie playback, photo viewing, PDF presentations, etc.


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