Re: [ft-devel] [OpenType] Question about LookupFlag (fwd)

[George Williams]

On Mon, 2005-04-04 at 00:50, Behdad Esfahbod wrote:
> I'm all confused about how one is supposed to handle LookupFlag.
> The OpenType spec once says [1]: "The LookupFlag specifies lookup
> qualifiers that assist a text-processing client in substituting
> or positioning glyphs."  and the LookupFlag bit enumeration
> defines:
Personally I've never understood what the point of "IgnoreBaseGlyphs"
and "IgnoreLigatures" might be. I can see contexts in which IgnoreMarks
might be useful (building ligatures in non-latin scripts perhaps), but
the other two seem pointless.

It also isn't clear to me why "right to left" needs to be specified.
Unless opentype is allowing support for boustrophedon scripts then
l2r/r2l is determined by the script which has already been specified in
the script/lang table. I've never seen any mention of boustrophedon in
the OT spec so I tend to doubt that interpretation...

I expect you need to find someone from Adobe/MS who really worked on the
OT spec to explain it. And since they didn't answer...