Reporting my findings on Action 123 (http://www.w3.org/Fonts/WG/track/actions/open)

Folks,

<Rant>
With the Thanksgiving holidays and all travel behind I came back at the office to a backlog of over 500 emails in my Inbox. Some folks clearly don't like holidays and prefer to work overtime - I figured that it may be a good day to forget about emails and just do something else instead, like e.g. exploring on-curve point optimization. :)
</Rant>

Here are the preliminary results (attached) - so far I ran the test only on the fonts I have installed on my computer (without prejudice). The numbers reported are:

-          total number of all points for all contours defined in a 'glyf' table;

-          number of on-curve points where their coordinates can be predicted *precisely* by using the coordinates of two adjacent off-curve points (and, therefore, the actual coordinates can be eliminated from the pre-processed output by simply using one reserved bit in 'flags' field to mark the point as "predictable"), and

-          percentage of points that can be predicted, per font.

As you can see, while individual font results vary significantly, the average number of all points that can be predicted [with respective coordinates eliminated as redundant info] is about 1.42%. Considering that point coordinates may use either one- or two byte formats - the actual file size saving is likely to be somewhat smaller, my guess it would yield the savings of around 0.7-1% (this statement has not been evaluated by the FDA!)

Let's discuss this over email and during the call tomorrow and see if there is a desire to do more about it.

Cheers,
Vlad