[lucida] Bounding box of plus sign in LucidaBrightOT

Bruno Voisin bvoisin at me.com
Sun Jan 24 20:05:39 CET 2016

> Le 24 janv. 2016 à 18:05, wettstae at gmail.com a écrit :
> Sorry, I messed this up.  The plus sign in the TrueType version fits its
> bounding box.  The the issue seems specific to the OTF version.

This will have to be confirmed by people more knowledgeable in layout engines and font rendering than me, but based on a discussion on another list I was under the impression that:

- PS Type 1 fonts are accompanied by metrics (AFM or TFM files) that provide preset bounding boxes for each glyph.

- TrueType fonts include I imagine the same data in one form or another.

- OpenType fonts do not include these data. It is the layout engine (included in XeTeX and LuaTeX) that calculates the bounding box based on the glyph outline. Hence all the handmade knowhow that was included in the TFM files is lost.

Again, I may be wrong, as I'm really not an expert in those things. In particular, the discussion on that other list seemed to make a difference between the math fonts and the text fonts, which do not include the same tables. But this is really way above my understanding of fonts.

Bruno Voisin

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