Scaling user interface for HiDPI displays

Jarno Suni j_suni at
Thu Apr 28 20:48:56 CEST 2016

> On Wednesday, April 27, 2016 7:21 AM, killermoehre <killermoehre at> wrote:

> > Am 26. April 2016 19:29:20 MESZ, schrieb Jarno Suni <j_suni at>:
>> Firstly, I think the Custom DPI setting is misleading term in Appearance 
> settings, as display's resolution (or display's physical size) do not 
> change by the setting.
> No, but you can change with that the default 96 dpi set by X.
>> It could be named as text scaling factor or something.
> It scales more than just text (at least in theory).

It does not scale panel thickness or title bar's thickness.

>> What I miss is ability to use different scaling factor for different 
> monitors, when using extended desktop since text on some high DPI monitor might 
> be hard to read from the same distance than you use a low DPI monitor from. I 
> think ideally user interface elements would have the same effective physical 
> size in both monitors even if the monitors have different physical dimensions 
> and display modes, if user uses both monitors from the same distance.
> Yeah, no. X doesn't support this. You would need multiple X-Server per 
> monitor. Go ahead and try with »xrandr«.
>> Maybe better place to set monitor specific scaling factor would be in 
> xfce4-display-settings instead of Appearance settings.
> Well, the display anounces its size, so it could be even autodetected. But even 
> than you need multiple X.
> Maybe Wayland will fix this.

This illustrates scaling in Unity:
AFAIK Unity is still using X in Ubuntu, but there are plans to use Mir display server in the future.

It seems you need to change several settings in order to make most apps scale nicely in Unity, too:

Jarno Suni -

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