Re: search for better regtest comparison algorithm

[Werner LEMBERG]

> And mind you: we need _tests_ not just the images, I want to
> investigate if making the images in a different format helps
> (with/withou aa, messing with resolution, ... whatever the case
> might be)

The case at hand is Harm's current work, i.e.,

  https://gitlab.com/lilypond/lilypond/-/merge_requests/2391

You create a regression test baseline (i.e., calling `make
test-baseline`) using the commit before this MR, then you switch to
the MR's branch[*] and say `make check`, which eventually creates

  .../out/test-results/index.html

telling you that there is one test below the threshold, and this is
the one in question!


    Werner


[*] After a MR has been merged you have to create a branch locally and
    apply the changes manually.