Talk:Metric-compatible fonts

Accuracy

User:J.mlr correctly points out that some of the fonts here are not metric-identical, and others are just "similar". Metrics are indeed a bit of a headache; there are about two classes of relations we can distinguish on this page:

• "Works in PDF substitution" is what we are mostly doing here. Because the metrics are not directly used to typeset, a little bit of difference in metrics is okay.
• "Works in LibreOffice and TeX, does not change layout" is very strict. I've read somewhere that even a tiny change can result in unbounded differences in line / page-break decisions down the line, as typesetting algos tend to not be not very stable with regard to metric diffs, but I can't find the source.
  • The GUST people also described how the OTF format does not allow for full compatibility with the original Computer Modern.
  • The TeX Gyre people have also abandoned the goal of trying to stick with Adobe metrics.
• There might be some kind of "close enough for not send most documents flying", but I don't know how we can quantify that. Given the same line height, a limited amount of horizontal difference, and a document with not-too-long paragraphs, there has to be some kind of weak consensus as to line and page break decisions.

Arthur2e5 05:47, 10 May 2024 (UTC)