[Development] QTBUG-95930 / QTBUG-99546 need some attention

Morten Sørvig Morten.Sorvig at qt.io
Tue May 10 21:40:02 CEST 2022

> On 9 May 2022, at 16:47, Thiago Macieira <thiago.macieira at intel.com> wrote:
> On Monday, 9 May 2022 07:07:23 PDT Morten Sørvig wrote:
>> b) In practice, QT_SCREEN_SCALE_FACTORS has become a system setting since
>> it’s being set on behalf of the user. This means the values should be
>> subject to rounding according to highDpiScaleFactorRoundingPolicy property,
>> like with other system DPI settings.
> It it's a system setting, then one should assume it's been set to the exact 
> value that the system wanted it to be. So if they'd wanted it rounded, they'd 
> have rounded it.

That is true, however the purpose of highDpiScaleFactorRoundingPolicy is override the system setting. For example, a Windows display can be configured for 175%,  but the app knows it does not support that and has enabled rounding (to 200%). 

So if QT_SCREEN_SCALE_FACTORS is considered a system setting then this is an inconsistency  in behavior.


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