AHG conference call minutes - Oct 29th, 2008

[Levantovsky, Vladimir]

 Dear all,

Thank you for active participation in the conference call. Please see
below my notes from the conference call, any additions and corrections
are welcome and appreciated.

Conference call start at 21:00 UTC.

Attendees:
Simon Daniels (Microsoft), 
Michelle Hill (Microsoft), 
Sergey Malkin (Microsoft), 
Thomas Phinney (Adobe), 
Sairus Patel (Adobe), 
Kamal Mansour (Monotype),
Vladimir Levantovsky (Monotype), 
Behdad Esfahbod (Red Hat)

Subject of discussion: Multiple Mark attachments proposals
1. Proposal from Kamal Mansour (Monotype)
http://groups.yahoo.com/group/mpeg-OTspec/files/Kamal%27s%20Mark%20Attac
hment%20Type%20proposal%20modified%2020080908.doc 
2. Proposal from Sergei Malkin (Microsoft)
http://groups.yahoo.com/group/mpeg-OTspec/files/Mark%20attachment%20filt
ering%20using%20mark%20glyph%20sets.docx 

Summary of discussion

The group has reached consensus that having multiple mark attachments is
a benefit and should be implemented in the currently developing
specification.

Two proposed technical solutions accomplish this goal by allowing
lookups to filter mark glyphs with arbitrary sets of marks. Kamal's
proposal suggest to extend Lookup table functionality by defining array
of multiple mark attachment types while Sergei suggested to introduce
new GDEF structure (and introducing the new version 1.2 of GDEF table)
that would define mark glyph sets, and then index them in the Lookup
table. Behdad expresses a concern that Sergei's approach may impact the
performance. The general agreement in the group is that the
functionality supported by either solution is unique and is unlikely to
be a significant part of a font data processing, therefore a potential
impact on the performance is negligible.

The group consensus is that Sergei's proposal to introduce global
storage of (possibly intersecting) mark  sets and indexing them in the
lookups is advantageous, and is more elegant solutions that is also
backward compatible - introducing new GDEF version will prevent any
conflict with existing implementations.

Action items: 
- Michelle and Sergei to finalize the text of the proposal and to send
the suggested changes to the group.
- Since the text of the standard is currently under FCD ballot, the
updated proposal will be submitted through the respective National Body
as FCD ballot comments.
- The AHG recommendation is to approve the proposed changes (since
Kamal's proposal has been already incorporated in the current text.

Conference call adjourned at 21:57 UTC.

Thank you,
Vladimir