Re: [ft] Problem using Apple sbix format ttf file

[Werner LEMBERG]

In March, Nick asked the following:

  Using the latest freetype 2.5.3 the Apple Color Emoji.ttf file on a
  Mac works fine. However freetype fails to load the glyphs using an
  iPhone's address@hidden' file.

  It looks like either the iphone sbix format used is slightly
  different, or the png format has been customized...?

I've now had a closer look, and I can finally answer it :-) The format
of this font's sbix table is indeed different.  It uses an `rgbl'
graphic type, which is officially unsupported by Apple, according to
the recently published sbix specification.

  
https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6sbix.html

It shouldn't be too hard to implement the `rgbl' type in FreeType,
since it appears to be an uncompressed format with four bytes per
pixel, but I doubt that it makes sense, given the fast pace of iOS
versions.

I suppose that recent emoji fonts of Apple use one of the much more
compact formats like `png' that should shrink the font size a lot.


    Werner