A supposedly patent-free suggestion/solution to the curious subpixel rendering in Fedora

Jud Craft craftjml at gmail.com
Fri Mar 27 20:14:52 UTC 2009


I didn't know myself for sure whether it [Qt's filter code] was
patent-infringing.  But I did know:

1.  Fedora tries not to ship patented technologies.
2.  Fedora took subpixel filtering (due to its possible infringement)
out of the desktop stack.
3.  Qt has its own separate filtering code.
4.  Fedora did NOT remove the Qt subpixel filters.

Hence I began to wonder if A) Qt's filtering technique was considered
as non-infringing, and B) if so, why not just use that for the rest of
the X stack?

But now I know the answer, that it really was infringing, but
apparently Fedora didn't catch it, because they assumed Qt just used
whatever filters everybody else used, without having duplicate
filtering code of its own.

I was wrong, but my thought process wasn't horrible flawed.  I figured
Fedora had already figured this stuff out (after all, I am not a
lawyer, but I thought certainly Fedora was on good legal ground), and
yet there was an incongruity about their enforcement (Qt gets filters
while the rest do not).  So I concluded either A) Qt's filters were
patent-safe, or B) Fedora missed it, and stupid me, I gave Fedora the
benefit of the doubt.  But I apologize for making a big deal about it.




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