Fallback decorations use pre-scaled window->wl.{width,height} for sizes, but don't send the factor itself.

Fallback decorations should now be correct

any updates on this?

Due to time constraints I've paused work on the protocol and implementations for now. It'll probably be a few months before I continue working on it.

@Zamundaaa set_scale_factor is NOT part of the v1 protocol that was merged and implemented. https://gitlab.freedesktop.org/wayland/wayland-protocols/-/merge_requests/143
please rework to function with v1 of the protocol if possible

it is part of the v2 protocol that as of now is unmerged and not implemented anywhere:
the PR name is wrong, this is v2 https://gitlab.freedesktop.org/wayland/wayland-protocols/-/merge_requests/149
protocol xml is v2 staging/fractional-scale/fractional-scale-v2.xml

I know, I'm the author of the now-v2 protocol. You're right though, the title of this needs updating

maybe I am missing something but isn't the fractional scaling protocol supposed to allow for rendering at the native monitor resolution?

with kwin wayland 5.27 (fractional scaling v1 implemented) and the decoration fallbacks from this PR removed (so it can build and be used), my scaling factor is 1.5, and my native monitor resolution is 3840x2160, but I am rendering at 2560x1440 with this PR

I am also here to report that cursor is broken in minecraft with this PR applied to master. works correctly on wayland (building with wayland, no x11) without this PR

This PR is not compatible with the v1 protocol, it will cause wrong behavior. It's really not ready for testing until I pick up work on the v2 protocol again and update this PR for it

Just dropping in to say that I do want GLFW to support this protocol and also that you don't need to keep this rebased and current for it to be reviewed and accepted when I get the time to do so. There's likely going to be a lot of changes in the Wayland code soon but the automated merge status going red will not affect whether it's merged (although if you prefer to do the rebase yourself, please let me know).

thanks. I would prefer to rebase it myself once I continue working on it, but I'll ask for help with that if needed

Hello again, I'm about to implement support for fractional-scale-v1. Is fractional-scale-v2 still under development and if so is there anything in particular I should be mindful of when implementing support for v1?

Yes. After we found some fun problems coming down to the fractional-scale-v1 approach in recent KWin development, I'm picking up v2 again. For implementing v1, as long as you keep the v1 protocol optional there shouldn't be any additional hurdles for implementing v2.

To potentially save you some time with v1, if you're testing the implementation on Gnome, if you see gaps and/or overlaps between the window content and the decoration, that is sadly expected with some scale factor + window size combinations. v1 is incompatible with subsurfaces and thus libdecor's approach to client side decorations.