[MPEG-OTSPEC] 'opbd' feature

[Laurence Penney]

> On 17 Sep 2020, at 00:21, John Hudson <john at tiro.ca> wrote:
> 
> Because of the amount of work involved in defining lfbd and rtbd GPOS lookups (and the current lack of any very convenient visual editing tool), I don't imagine it being something a lot of font makers would do for a lot of fonts

IMO it would be worth exploring the radical idea that a glyph’s left and right boundaries become the *standard* horizontal type design metrics (just as we think of alignment to vertical metrics, with overshoot etc.). There would be separate specification of padding-left and padding-right (usually equal) which would be consistent across the font (but varying according to wdth, opsz etc.). On export, the type design app would pad every glyph so that the font is spaced normally. The app would also add suitable lfbd/rtbd GPOS lookups, of course.

- Laurence