OpenType Feature Format

Michael Jarboe
Michael Jarboe Posts: 265
edited November 2015 in Type Design Technique & Theory
I was looking closer at an OpenType 'zero' feature for the slashed zero replacement and realized it was written out using each grouping bracketed rather than having each separate grouping designated as a class.

Written like 
sub [zero zero.op zero.lt] by [slashzero slashzero.op zeroslash.lt] 
as opposed to 
sub @zero1 by @zero2

I was just curious about this as it all gets decompiled so is it simply a case of the feature being easy enough to write out vs. using classes?
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Comments

  • Erin McLaughlin
    Erin McLaughlin Posts: 45
    Yes, they're the same. Probably just a short enough list that someone didn't want to write a class.
  • Khaled Hosny
    Khaled Hosny Posts: 302
    Both lines  are using classes, the first are just unnamed classes. But anyway it is just syntactic sugar, substitution lookups does not use classes, so both are the same as:
    sub zero    by slashzero;
    sub zero.op by slashzero.op;
    sub zero.lt by zeroslash.lt;


  • María Ramos
    María Ramos Posts: 100
    The good thing about creating classes is that you can use it in different lookups, without having to write the groups down more than once. If you are just going to use that group just once then you don't need a class.

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