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RE: [ft-devel] Possible solution for TrueType patent problems...

From: David Turner
Subject: RE: [ft-devel] Possible solution for TrueType patent problems...
Date: Mon, 06 Nov 2006 19:15:26 +0100

> Two of the three patents have already expired, which may be helpful.

that's not true, because law is a bit subtle here.

the patent expiration rules are now the following:

- if the patent was filed after 1995-06-7, its expiration term is 20 years 
after the filing date.
- if the was filed before 1995-06-07 and after 1978-06-08, then the term is 17 
years from the issuing date

the patent that cover some of the TrueType bytecode instructions are US 
5,155,805 and US 5,159,668
which were both filed on 1989-05-08, so the second rule applies, and we need to 
look at their issuance
dates to determine their expirations.

they are, respectively, 1992-10-13 and 1992-10-27, corresponding to expiration 
dates of:

  5,155,805:  October 13, 2009
  5,159,668:  October 27, 2009

note that there is also an additionnal patent, namely US 5,325,479 which was 
filed in 1992. It took me a
very long time to realize what its purpose is, because the wording is extremely 
similar to the 805 one;
and it struck me that this third patent covers *approximations* to the exact 
computations covered by
the 805 patent. Apparently, someone at Apple realized that you didn't need to 
get 100% accurate
results in the outline distortion to get equivalent bitmaps :-) Fortunately, we 
don't need to deal with this
patent at all.

And don't forget that there are equivalent EU, UK and FR patents (at least), 
which may have been
filed later, with even later expiration dates.

So we simply can't write this problem off :-(

Hope this helps,
On Mon, 6 Nov 2006 16:45:42 -0000, "Graham Asher" <address@hidden> said:
> Two of the three patents have already expired, which may be helpful.
> Graham Asher
> _______________________________________________
> Freetype-devel mailing list
> address@hidden

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