[Development] Respecting QGuiApplication::highDpiScaleFactorRoundingPolicy on Wayland

[Tor Arne Vestbø]

> On Sep 9, 2024, at 9:03 AM, Ilya Fedin <fedin-ilja2010 at ya.ru> wrote:
> 
> While most platforms seem to have fractional scaling via
> QHighDpiScaling, Wayland is the first (and the only right now) platform
> that got fractional devicePixelRatio on QPA level. QHighDpiScaling
> doesn't handle that and the Wayland QPA just disables fractional
> scaling support when it sees the policy is not PassThrough.
> 
> It's good that it does that at least but I believe this could be done
> better. I have patches that make High DPI rounding policy to behave on
> Wayland the same as on other platforms, allowing applications using a
> rounding policy to render 1:1 with crsip fonts (currently the
> compositor downscales as QPA disables fractional scaling support) and
> actually respect the policy (downscaling means it's effectively always
> Ceil).
> 
> Is there any interest in those changes?

Yep, please share the patches. Doing so makes it easier to see how this fits within the existing architecture :)

Cheers,
Tor Arne