Lag when switching between Stage manager tasks (macOS Ventura)

[noefroidevaux]

What Operating System(s) are you seeing this problem on?

macOS

Which Wayland compositor or X11 Window manager(s) are you using?

-

WezTerm version

20220905-102802-7d4b8249

Did you try the latest nightly build to see if the issue is better (or worse!) than your current version?

Yes, and I updated the version box above to show the version of the nightly that I tried

Describe the bug

When I switch between State manager tasks on macOS Ventrua, the animation is fluid... but when I switch from/to WezTerm, the animation is very laggy. The lag is more visible when the window of WezTerm is bigger.

To Reproduce

Use State manager on macOS Ventura and switch between tasks (including the one which has WezTerm).

Configuration

local wezterm = require 'wezterm'

return {
  font = wezterm.font "Iosevka Nerd Font Mono",
  font_size = 15.0,
  color_scheme = 'Dracula (Official)',
  window_decorations = "RESIZE",
  enable_tab_bar = false,
}

Expected Behavior

No lag when switching from/to WezTerm using macOS Ventura Stage manager

Logs

Many WARN wezterm_term::terminalstate > unhandled SetMode(Unspecified(34))

Anything else?

No response

[noefroidevaux]

Maybe it helps someone: my current workaround is to deactivate all macOS animations by activating System Settings > Accessibility > Reduce motion.

[zasdaym]

MacOS's poor OpenGL support likely causes this. Adding window_background_opacity = 0.999 in the config fixed the issue for me.

[wez]

Those that are experiencing this: are you on Intel or Apple Silicon?

You may wish to try adding:

front_end = "WebGpu"

to your config to use Metal rather than OpenGL. WebGPU is currently experimental:

• WebGPU front_end #2756

[zasdaym]

Those that are experiencing this: are you on Intel or Apple Silicon?

You may wish to try adding:

front_end = "WebGpu"

to your config to use Metal rather than OpenGL. WebGPU is currently experimental:

• WebGPU front_end #2756

Apple Silicon here. Using front_end = "WebGpu" has no effect, still lagging.

[noefroidevaux]

Also Apple Silicon here. I have also tried front_end = "WebGpu" without success.

[wez]

Can you try setting window_background_opacity = 0.9 to see if that influences this issue?

[noefroidevaux]

Can you try setting window_background_opacity = 0.9 to see if that influences this issue?

Yes, it's the case: with this setting, it seems smooth.

[wez]

Ok, I think we've re-discovered the findings from:

• ghostly text artifacts after clearing screen on macos with transparency enabled #310 (comment)

at that time we turned off window shadows on macOS to improve performance after troubleshooting some ghostly artifacts when using transparent windows and discovering that shadows always hurt performance.

Subsequently, shadows were restored for opqaue windows by:

• Only disable drop shadow on macOS when window background opacity is transparent #445

I just pushed a commit that allows you to do:

   window_decorations = "TITLE|RESIZE|MACOS_FORCE_DISABLE_SHADOW"

to force them to be disabled independently from the window_background_opacity. You can also use MACOS_FORCE_ENABLE_SHADOW if you wish.

I haven't put too much thought into whether the default behavior should change for this. I'm leaning towards making it fast by default, but I'm open to hearing input from others before committing to a change.

@fanzeyi: do you have strong feelings about this?

[fanzeyi]

Thanks for checking with me. Personally I feel a window looks weird on macOS if the drop shadow is not there, but I think it's largely just my preference.

So yeah as long as there is a way to get it back. I don't have strong feelings about what default it should be.

[noefroidevaux]

   window_decorations = "TITLE|RESIZE|MACOS_FORCE_DISABLE_SHADOW"

@wez I confirm that the lag is not here anymore with this config (version 20230320). As I use the term full screen, it's not a problem to not have the shadow. Thank you so much!

[noefroidevaux]

But now I have another problem 🙂 By adding MACOS_FORCE_DISABLE_SHADOW to RESIZE for window_decorations, I have now a transparent window bar.

With window_decorations = "RESIZE|MACOS_FORCE_DISABLE_SHADOW":

With window_decorations = "RESIZE":

Did I do something wrong? Or should I open a new issue?

[wez]

@noefroidevaux please open a separate issue for that!

[noefroidevaux]

@wez it's done :) => #3313

[martin-braun]

Bless you all, this issue was driving me nuts, because it didn't just affect the stage manager, but also Mission Control. Everything slowed down on any window animation until I added

window_decorations = "TITLE|RESIZE|MACOS_FORCE_DISABLE_SHADOW"

(But I also removed the TITLE for some nice headless window.)

Here is a visual comparison between iTerm and wezterm without the setting above, in case someone need something to relate to:

2024-01-23.12.10.57.mp4

With the above setting I can see there is no shadow on the window anymore, but it's finally snappy and all. I tradeoff worth making, but it would be great if this could be fixed for people in the future. It wasn't so easy to find this issue.