New OT discretionary feature: Legible forms (legi / lgbl) #15
Description
I’d like to propose registering a new user-discretionary (off by default) feature “Legible forms” (draft tag: legi or lgbl).
The feature provides a standardized way for font vendors to include glyph forms that increase the legibility of the characters. One typical example might be providing access to a “serifed“ letter “I” and a “bent” letter “l” in a sanserif design where the default forms of those letters are intentionally similar.
But a font vendor might provide access to other forms that visually disambiguate the characters (not just letters) from other confusables, in some cases perhaps across scripts.
Making such forms default may not always be a good idea, because such forms tend to be a bit “awkward” and may disturb the natural reading flow of continuous text.
Font vendors are already free to provide access to such forms via stylistic sets, and many have done so. But here we have a case of clearly defined purpose of the feature, and there would be some benefit of devising a dedicated tag.
Using legible forms may be the preferrable way to typeset proper names (places, people), in technical or geographical context, in contexts where differrent writing systems are used, in scholarly or educational publications, and anywhere where the reader may be exposed to unfamiliar formations.