Nested labwc is blurry when root labwc scaling is applied about labwc

[kyak]

I confirm that tinywl is blurry as well.

[kyak]

Need to say that running weston nested in labwc is also blurry.

[johanmalm]

Do you set scale on the nested output? (WL-1 IIRC)

[kyak]

Do you set scale on the nested output? (WL-1 IIRC)

I did, scaling in the nested labwc doesn't matter. It is blurry at all scales.

[Consolatis]

@kyak is this a regression compared to the last release (e.g. wlroots 0.16 based)?

Obviously we should fix it either way but that could help finding the actual cause.

[kyak]

@kyak is this a regression compared to the last release (e.g. wlroots 0.16 based)?

Obviously we should fix it either way but that could help finding the actual cause.

There is the same problem running labwc 0.6.6 release with wlroots 0.16.

[bi4k8]

I believe this has been the case for a long time--I don't recall having ever seen nested labwc be non-blurry, and my outer session runs at 2x scale.

[Consolatis]

Is tinywl (when running nested) blurry as well?

[kyak]

Is tinywl (when running nested) blurry as well?

tinywl doesn't currently build for me, reported here: https://gitlab.freedesktop.org/wlroots/wlroots/-/issues/3774

[Consolatis]

Hm.. if the latest merge of the fractional scale support didn't change anything either this seems like some more generic wlroots issue with the wayland backend. I am not actually sure what we could do here, neither from the main DRM session perspective nor from the nested wayland perspective.

[kyak]

Hm.. if the latest merge of the fractional scale support didn't change anything either this seems like some more generic wlroots issue with the wayland backend. I am not actually sure what we could do here, neither from the main DRM session perspective nor from the nested wayland perspective.

I just tried with latest master (fractional scaling included) - nothing has changed (nested labwc still blurry).

[Consolatis]

From a quick look at the wlroots wayland backend it actually doesn't seem to implement *anything* scaling related.
AFAIU this means that the generic scene graph scaling kicks in and that is blurry as heck as its just upscaling pixels rather than telling the source of the pixels (the nested labwc and thus the running applications within the nested labwc) to render in a bigger resolution.

A (bad) workaround would likely be to use scale 1 in the DRM labwc and scale 2 (or whatever scale is wanted) within the nested labwc.

[Consolatis]

As this is not a regression I'll remove the issue from the 0.7.0 milestone. We should still try to fix it but as far as I see this requires changes in the wlroots wayland backend.