Slint 1.14.1 with Software Rendering Spins CPU to 100%

[ekatwired]

Bug Description

After updating to Slint 1.14.1 CPU usage went to saturating it, when, as far as my measurements say, it spends most time on font rendering.

Reproducible Code (if applicable)

<https://gitlab.nic.cz/turris/peacockr/-/tree/ec7f4c407a1ba1ab3a13097341340df5c29f6bd2>

Environment Details

• Slint Version: 1.14.1
• Platform/OS: aarch64-unknown-linux-musl
• Programming Language: Rust
• Backend/Renderer: Custom Wayland Backend / Software

Product Impact

Saturates entire CPU on feature which isn't critical for device functioning.

Can keep it on 1.13.1 for the time being.

[ogoffart]

Thanks for reporting a bug.

Do you have any clearer step to reproduce?
I've tried compiling the provided repository, but it doesn't seem to work without a config file. (And even then I wouldn't know what to do to actually see the problem)

as far as my measurements say, it spends most time on font rendering.

Do you perhaps have more info like a flame-graph or trace that shows what exact functions are being slow?

[ekatwired]

Give me a moment, I am currently out of office, should arrive in hour and a bit. 5. ledna 2026 11:49:49 SEČ, Olivier Goffart ***@***.***> napsal:

…

ogoffart left a comment (slint-ui/slint#10370) Thanks for reporting a bug. Do you have any clearer step to reproduce? I've tried compiling the provided repository, but it doesn't seem to work without a config file. (And even then I wouldn't know what to do to actually see the problem) > as far as my measurements say, it spends most time on font rendering. Do you perhaps have more info like a flame-graph or trace that shows what exact functions are being slow? -- Reply to this email directly or view it on GitHub: #10370 (comment) You are receiving this because you authored the thread. Message ID: ***@***.***>

[ogoffart]

Would you be able to provide more information as how to reproduce?
Ideally with a smaller testcase.

[ekatwired]

Tried to make an reproduction but it happened on our (in some things specific) hardware and on 1.15 the issue no longer persists.

[ogoffart]

Good to know, thanks.