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implement extension substitution for gsub lookuptype 7 #113

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Pomax opened this issue Mar 1, 2021 · 0 comments
Open

implement extension substitution for gsub lookuptype 7 #113

Pomax opened this issue Mar 1, 2021 · 0 comments
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completion work to complete a feature that was started previously

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Pomax commented Mar 1, 2021

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.

This means calling buildSubtable(extensionLookupType, p where p is our parser, already pegged to the start of the substitution's byte offset.
@Pomax Pomax added the completion work to complete a feature that was started previously label Mar 1, 2021
@Pomax Pomax self-assigned this Mar 1, 2021
@Pomax Pomax mentioned this issue Mar 1, 2021
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