[ft-devel] The wrong face for the requested index is loaded with some dfonts

[Khaled Hosny]

Hi all,

Recently we switched to building FreeType for TeX Live on Mac without
the --with-old-mac-fonts option that we were using previously, and I
just found that there is an incompatibility in the handling of face
indices in dfont files between the old a new configurations.

For some dfont files (the old, dfont, version of Hoffler Text, the
Helvetica and Courier fonts bundled with MS Office for Mac, to give some
examples) the loaded face for a given index is difference, for example
Courier.dfont, index 0 loads "Courier-Oblique" while it should be
loading "Courier" as it does when configured with --with-old-mac-fonts.

This is because FT_Raccess_Get_DataOffsets() (in src/base/ftrfork.c) is
sorting the offsets by reference ID which do not always match there
order in the file. This was introduce in commit 540b954 to fix an issue
with HelveLTMM font, I'm not sure what to test in this font, but may be
the sorting can be limited to when "tag == TTAG_POST" or even "tag !=
TTAG_sfnt"?

Regards,
Khaled