[ttx] Could the sbix table support <extfileimagedata>?

[LIXiangChen]

I'm not trying to export the images from sbix font, but want to use .ttx file as a source file to build sbix font - You know that for build CBDT font, this is ok, but since <extfileimagedata> is currently not available for sbix table, this is not feasible.

Are there any plans to make it supportable, or any hacks?

[anthrotype]

thanks, it'd be nice to have that, but there's no plans at the moment. If you like to give it a go you're welcome.

you may also want to try nanoemoji which has a --color_format=sbix to build a sbix color font from a set of .svg input files.
It also comes with a separate maximum_color script which you can use to add a sbix table to an existing vector color font (either COLRv1 or OT-SVG), with the --bitmaps option, see its README.