These parameters were forgotten in bug 961365. They should be used instead of GetSubDropFromChild and GetSupDropFromChild, when available.

It seems that the old code uses the metrics of the scripts rather than those of the mmultiscripts element itself (as we do for getMathConstant). I'm not sure exactly what's the proper exact way to do that? And probably the same question arise for other parameters...

I never found a satisfying answer for this question, may be it is worth asking on the OpenType mailing list. My gut feeling is that reading the constants from the base font is the logical choice, testing against MS implementation might be a way to check this.

Thanks, I'm not exactly sure what you mean by the "base" font (the one of the <math> root ; or of the <mmultiscripts>, which also has the same size of its base by default). So I'll probably do as in the present patch, as it is consistent with what we do with other constants right now.

Comment on attachment 8702140 [details] [diff] [review] Patch V2 Review of attachment 8702140 [details] [diff] [review]: ----------------------------------------------------------------- Code seems fine to me (I didn't try it to see if it looks reasonable with the various math fonts, but I assume you're happy with the results it gives).