<Swing Dev> [9] Review request for 8058742: Text size is twice bigger under GTK L&F on Gnome with HiDPI enabled

[Sergey Bylokhov]

On 26.07.16 21:25, Semyon Sadetsky wrote:
>> Why it should be decreased? it should work as other components. But we
>> should use only one source of system scale information at a time. And
>> debug scale should have the main priority. Xft.dpi should affect jdk
>> in the same way as "text-scale-factor, text-scaling-factor".
> Please look at the code the fix is applied to. Native scale is in the
> divider.

Because we take care about scale twice, the first time as a global scale 
and the second time here. We should do this only in one place.

> This fix is not related to the whole jdk scale it is only about GTK font
> size. Taking Xft.dpi as a global jdk scale (not in this fix, of cause) would
> require an additional investigation. But the supported OSes provide
> refined scale info from xsettings.

It is actually directly related to the global scale, since support of 
Xft/ was added in JDK-4830281 as a way to scale java UI. And now the new 
solution and the old one conflicts. Can we skip the usage of gnome.Xft 
if default device scale is not identity (which means that some other 
scale factor is used)?

>>>>>> I think the logic should be:
>>>>>>  - Take debug scale into account if it was set and skip all others.
>>>>>>  - Check J2D_UISCALE
>>>>>>  - Check scale-factor, text-scale-factor, text-scaling-factor.
>>>>>>  - Check Xft.dpi.
>>>>>>  - If non of them was set then scale=1 should be used.

-- 
Best regards, Sergey.