Why is the slider lagging behind the mouse?

[flosse]

When I compile the slider example examples/views/slider.rs (in release mode, of course), the slider is quite sluggish.
When I compile it with the baseview feature, it's just as you'd expect.
Why is that? Is there a latency between the emitting of the change event and the handling/update of the model?
With such a simple graphic, it's probably not the rendering, is it?

My system: Linux, Wayland, i7

[geom3trik]

Hmmm that is strange. I'm not sure why the baseview backend would work and not the winit one. The mouse won't perfectly stick to the slider thumb due to the double buffered nature of the opengl rendering but for such a small example and in release mode I wouldn't expect you to notice. I'll try to look into this but I can't replicate this issue currently and I don't have a Linux machine. Which suggests that it might be something to do with winit on wayland.

[geom3trik]

Good point, I've always used the same wireless mouse, but unfortunately it's the same with a wired USB mouse 😞

😞

Okay, maybe when I add more debugging tools to vizia it will become easier to figure this out. Unfortunately until I can replicate this I'm not sure there's much I can do. I'll try it on some other computers I have tomorrow and see what happens.

[geom3trik]

The long_list example is extremely slow. And 1000 items are not more than a few. I wouldn't expect that.

There's some optimisations on the views-update branch that should fix this. Long story short, styling was much slower than it should be. If you found vizia via the reddit post then I apologise because vizia isn't quite ready for prime time, but it's very close.

[flosse]

I don't want to compare apples and oranges here, but with egui there is no such problem. Everything runs smoothly even on the 18 year old centrino.
Please don't take it the wrong way, I don't want to make anything bad here, on the contrary, because I think Vizia is so incredibly good, I want to contribute to making it even better ☺️
Thanks in any case for all the work so far and the great framework!

[geom3trik]

I don't want to compare apples and oranges here, but with egui there is no such problem. Everything runs smoothly even on the 18 year old centrino.
Please don't take it the wrong way, I don't want to make anything bad here, on the contrary, because I think Vizia is so incredibly good, I want to contribute to making it even better ☺️
Thanks in any case for all the work so far and the great framework!

No I totally understand, a GUI framework shouldn't be laggy for such a simple example, and I'm sorry it's not working correctly. Just one last attempt, by any chance is the slider example on the views-update branch any better?

[flosse]

I am very sorry, but unfortunately there is no change to be seen there either. I have also removed all labels and the example page, but the problem still persists (see video)

Bildschirmaufzeichnung.vom.2024-01-28.01-17-39.webm

[uklotzde]

I cannot confirm this issue on Fedora 39 on Wayland.

cargo run --no-default-features --features wayland,winit --example slider

No noticeable latency, even in debug mode.¹

Footnotes

1. On an ancient Intel Skylake machine. ↩

[uklotzde]

Screencast.from.2024-01-27.17-22-37.webm

[flosse]

Here is how it looks like on my machine:
Bildschirmaufzeichnung vom 2024-01-27, 17-57-50.webm

And here with baseview
Bildschirmaufzeichnung vom 2024-01-27, 17-59-33.webm

edit:
It feels very similar on a Mac mini, i5, Intel HD 4000

edit 2:
It's the same on an old 32 Bit Intel Centrino with Linux and X11