What is the difference between TrueType and OpenType?

[ErwinDenissen]

Hi Fred,

@Fred Goldman

You’re right it really makes no sense that the DSIG table should be the deciding factor on what is shown as an OT font.

Yes, I wonder when Microsoft decides to change this odd behavior.

@Fred Goldman

Come to think of it, in order to get a DSIG don’t you need to have either a GSUB or a GPOS table in the font?

No, the Microsoft font signing tool can sign both TrueType and OpenType fonts. If you sign a font, a DSIG table is added to the font file. Since the DSIG table is part of the OpenType font format (and not part of the TrueType font format), a signed TrueType font is automatically upgraded to be an OpenType font.

More about font signing and the DSIG table:
DSIG - Digital Signature Table
Digital signatures for font files
OpenType font signing tool