Font formats
OpenType item variation delta
Trace region scalars and one delta row in a logical ItemVariationStore.
Your inputs
Start with an exampleYour result
Example resultAa — A small example of your colors.
How it works
Compute each region’s per-axis support scalar, multiply across axes and sum the selected row using its regionIndexes order. Optionally add the net delta to a supplied base value.
At coordinates 0.5/0.25, region scalars are 0.5 and 0.125. The indexed deltas contribute 10 + 10, taking base 500 to 520.
Limits
Logical JSON only, with already normalized and avar-adjusted coordinates in −1…1. No binary font decoding, axis normalization, shaping or final rounding. Null subtables contribute zero; absent/out-of-range indexes reject. Up to 64 axes and bounded region/delta tables. Invalid or zero-peak region axes follow the specification’s ignore-axis rules with diagnostics.