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A comment on Why SQLite Uses Bytecode. Parent comment

Re:Why SQLite Uses Bytecode by xymostech on Tuesday April 30, 2024 @11:38AM (#40212251)
The original TeX Fonts stored their metrics in TFM (short for TeX font metrics) files, which contains a bytecode interpreter for calculating ligatures and kerning between characters. I learned about that when I tried reading the files myself.

From what I can tell, modern fonts using OpenType just have tables to accomplish something similar now, in the form of the GSUB and GPOS tables?

Documentation for the TFM format here: https://tug.org/TUGboat/Articles/tb02-1/tb02fuchstfm.pdf (search for lig/kern)

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Re:Why SQLite Uses Bytecode by atombender on Tuesday April 30, 2024 @04:09PM (#40215705)
TrueType (and OpenType, which is an evolution of TT) absolutely includes a bytecode instruction set: https://developer.apple.com/fonts/TrueType-Reference-Manual/...
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Re:Why SQLite Uses Bytecode by xymostech on Wednesday May 01, 2024 @08:31PM (#40231384)
Oh yes, thank you for the link to that! Looks like that is an instruction set for representing the font glyphs themselves? I was talking about the instruction set in TFM which is for representing meta information, like ligatures and kerning between glyphs, and not for the actual glyphs. The glpyhs for the original TeX fonts are described using Metafont which is an interpreted language.
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Re:Why SQLite Uses Bytecode by atombender on Thursday May 02, 2024 @05:03AM (#40234156)
Glyphs are generally defined as pure outlines (the "glyf" table [1]), and the instruction set is an optional system for things like grid fitting. Ligatures, kerning etc. are normal tables.

[1] https://developer.apple.com/fonts/TrueType-Reference-Manual/...

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