Open Pomax opened 3 years ago
As per https://docs.microsoft.com/en-us/typography/opentype/spec/gsub#lookuptype-7-extension-substitution the lookup type 7 table is "actually not this, but a different lookup table", where the extensionLookupType field tells us the class we'll need to parse the table data as, and extensionOffset tells us where that table data starts.
extensionLookupType
extensionOffset
This means calling buildSubtable(extensionLookupType, p where p is our parser, already pegged to the start of the substitution's byte offset.
buildSubtable(extensionLookupType, p
As per https://docs.microsoft.com/en-us/typography/opentype/spec/gsub#lookuptype-7-extension-substitution the lookup type 7 table is "actually not this, but a different lookup table", where the
extensionLookupTypefield tells us the class we'll need to parse the table data as, andextensionOffsettells us where that table data starts.This means calling
buildSubtable(extensionLookupType, pwhere p is our parser, already pegged to the start of the substitution's byte offset.