Comment 6 for bug 1700085

On Ubuntu 17.10 default (gnome) / nvidia 1050Ti - 384.59 / monitor 3840x2160:

First, through gnome-tweaks it scale could be set to an integer 1,2,.. and for fonts to a different values 1,00, ...

Now, no hidpi option (the 1,2,..) exists on gnome-tweaks.

Ideally, hidpi could be set automatically depending on monitor size and resolution.

Less ideally, it could be an option like unity's system-setting with more values (1, 1.5, 2, 2.5, 3, ...) For example in my case 1.5 was far better than 2 that I am using now (and there is no option to change it again)