[Bug] high CPU usage when scrolling

[craftyguy]

Thanks for taking the time to file a bug.
Fill in what you can; if a section doesn't apply, feel free to remove it.

Your setup

• SONE version: 0.19.0
• Install source: flatpak/flathub.org
• Distro + version: postmarketOS "edge"
• Desktop / session: COSMIC 1.0.16
• GPU + driver: Mesa 26.1.1, asahi GPU (macbook M2)

What went wrong?

when scrolling in the app, CPU usage for WebKitWebProcess is 100% and the UI is very sluggish

What did you expect to happen?

fluid scrolling, and low CPU usage

How can we reproduce it?

1. open app
2. scroll on a page that's longer than the display height

Screenshots or recordings

Logs

Log output

Anything else?

It looks like the flatpak is configured with sw rendering only:

❯ flatpak info --show-permissions io.github.lullabyX.sone
[Context]
shared=ipc;network;
sockets=fallback-x11;pulseaudio;wayland;x11;
devices=dri;

[Session Bus Policy]
org.kde.StatusNotifierWatcher=talk

[Environment]
WEBKIT_DISABLE_COMPOSITING_MODE=1

I can "fix" this issue if I unset that env variable to enable compositing in webkit:

❯ flatpak override --user --unset-env=WEBKIT_DISABLE_COMPOSITING_MODE io.github.lullabyX.sone
❯ flatpak info --show-permissions io.github.lullabyX.sone
[Context]
shared=ipc;network;
sockets=fallback-x11;pulseaudio;wayland;x11;
devices=dri;
unset-environment=WEBKIT_DISABLE_COMPOSITING_MODE;

[Session Bus Policy]
org.kde.StatusNotifierWatcher=talk

[Environment]
WEBKIT_DISABLE_COMPOSITING_MODE=

Then scrolling (and CPU usage) is fine

One last thing

• I had a quick look through existing issues and didn't see this one already reported.