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

Jud Craft craftjml at gmail.com
Fri Mar 27 19:34:51 UTC 2009


Sir, the subject is not false.  You may be a text-stack-maintainer,
but I am not a moron.

>From the article:
-----
"However, since Qt4 was released, Freetype has added support for doing
subpixel rendering and filtering itself, along with several settings
for which filter to use.

In Qt 4.5 we will use Freetype’s filtering if available..."
-----

>From this, we clearly see that Qt has only started to use Freetype's
filter, in a version of Qt that Fedora hasn't even shipped to F10 yet.
 Ergo:  Qt has actually had its own filtering code independent of
Freetype for some time (I imagine analogous to Xft and Cairo in those
articles from David Turner the guy above linked to).  And, here's
more:

-----
"Note that the filtering we use in Qt 4.4 and earlier is pretty much
the same as Freetype’s default filtering..."
-----

They obviously have developed their own filter code (see above),
sometime before Freetype removed their own built-in LCD-specific
filtering.  The final result is apparently comparable to Freetype's
old (patent-infringing) filters.

If you want to double check me, then actually try _running_ a Qt
program in Fedora with RGB rendering on.  You'll notice the filtering
looks a heck of a lot different than GTK programs.

I am not trying to be deceptive or waste anyone's time.  I genuinely
thought this was something to look into.  Yes, I could be wrong and
Qt's filter could also patent-infringe.  But I have already mentioned
all of this.  I am _not_ wrong that Qt has their own independent
filtering code.

I am sorry I started the discussion.  Patent law is not my forte, but
I did come in with _some_ understanding of how the X text stack works.




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