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

[Semyon Sadetsky]

On 7/26/2016 1:23 PM, Sergey Bylokhov wrote:
> On 25.07.16 20:56, Semyon Sadetsky wrote:
>> But the font doesn't need to be scaled if JDK supports scale already.
>> Before the scale support is added to JDK the native scale was supported
>> for GTK LnF only and using fonts size only. I kept this simplified scale
>> support for compatibility with Linux OSes for which native scale is not
>> supported. For Qt based WMs for example.
>
> The question was why the native scale is taken into account, but debug 
> scale not. In this case we will get a different results if the native 
> scale=2 was read from J2D_UISCALE/scale-factor/GDK_SCALE/Xft.dpi or 
> was set for debugging by the user.
I have answered you already the GTK font size will be unexpectedly small 
if divided on debug scale.
>
> 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.
Did you try to use scale from Xft.dpi? Its value is not a scale usually.
Anyway, the above is about a global scale, so it is unrelated to the 
original issue which sounds like "Text size is twice bigger under GTK L&F".
>
> I guess text-scale-factor, text-scaling-factor are text related 
> scales, but we use it as a generic one, so why Xft.dpi should be 
> different?
>