On 26/12/2022 11:10, martin rudalics wrote:
>  > Aaand, here you go:
> 
> So far I'm pretty sure that we have some rounding problem here - maybe
> due to scaling.  The last version of my patch is attached, please use
> that for further experiments.
> 
> Now first do what you have done so far (three iterations) and post the
> results.
> 
> Next, if possible, try to turn scaling off, do the same experiments and
> post the results.
> 
> Finally, with scaling turned on again, start Emacs with
> 
> --eval "(setq frame-resize-pixelwise t)"
> 
> do the same experiments and post the results.

Here you go, three attachments.

As you previously guessed, the effect didn't show up when the scaling 
was off, or when resize-pixelwise was enabled.