"setting a scale factor of two" is a much too simple logic IMO. There should be a number of scaling option (a logarithmic scale for this would obvious).

Besides I am the user and I want controls (per monitor if there is more than one) so that I can tune it to my taste, the quality of my monitor(s) and the applications I use. It is OK that the desktop has a reasonable default, of course, but user controls could be at least "very_small .. small ..normal/default .. large ..very_large" for instance. System should not take control(s) away from user.

I accept that there is an ongoing process, and it is not simple nor trivial. Various mainstream Linux desktops should agree on a common mechanism (so that it will work for KDE applications running in Gnome, for instance). But that is of course also not easy. I don't think the developers of different desktops communicate much and they use different 'abstraction layers' (various versions of qt and GTK as well as X11 versus Wayland (soon)) for development. 

-- Peter

On Sun, Jan 11, 2015 at 10:51 AM, drago01 <drago01@gmail.com> wrote:
On Sun, Jan 11, 2015 at 12:07 AM, Peter Laursen <jazcyk@gmail.com> wrote:
> @drago1 .. you have posted two confilcting statements.
>
> Frist you stated that if *the vertical resolution* ...  And you even wrote a
> specific number (1440)

No I did not Florian did. And he meant "a high dpi display with a
vertical resolution of 1440" not "any display with a vertical
resolution of 1440"

> Next you stated that if *the DPI* ...
> .. there is no simple correlation between monitor resolution and DPI (as
> monitors have different size).

Yes I know a hidpi display is one with ... a high dpi value ;)

What GNOME does is basically this: If the DPI (computed from screen
size *and* resolution) is bigger then 192 it will turn on hidpi
support which means
setting a scale factor of two.

So if you have 2560x1440 display with a size of 22 inch .. it won't do anything.
If you have a 2560x1440 display with a size of 12 inch ... it will
turn on hidpi scaling.



--
Hilsen / Regards

Peter Laursen