[vlc-devel] Using VLC 4.0.0 on WSL2 Ubuntu 25.04 with wayland

[Rémi Denis-Courmont]

Nack.

Le 23 juin 2025 18:57:26 GMT+03:00, "Fatih Uzunoğlu" <fuzun54 at outlook.com> a écrit :
>> Who said you shouldn't use the viewporter for the interface? You just can't instantiate it for the video surface.
>
>Qt itself uses it for the interface surface since version 6.5. The video surface, when embedded, is expected to use the same scale the interface surface uses so that it fits perfectly.

Of course not. The display is expected to pick a scale according to VLC video settings.

>One might say, why not report the size as `size * scale` instead of using viewporter.

That's how it's supposed to work. That's how it works for all other displays, all other providers, Win32 and X11, and how the core makes its calculations.

If you don't respect that convention, this is 100% a bug in the Qt module. I shouldn't have to explain something like that.

>> That's a server/driver restriction, not a provider restriction.
>
>I say that with proper justification, provider can impose additional restriction (only) when it is used. Imagine if there was no such `EGL_KHR_display_reference` at all, then we would not have EGL display just because some provider needs it?

You can't add restrictions on how the display module is using the surface for rendering.

The EGL instance(s) are tied to the (wl_)display, not the (wl_)surface, which is a different story.

Again, the distinction should be effing obvious but the reference counting is a requirement of the (EGL) display module on the Wayland display server and the EGL driver. It's not a requirement imposed by the provider module on any display module. We don't do the latter; that was the whole damn point about splitting provider and display modules to begin with.