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

Jud Craft craftjml at gmail.com
Sun Mar 22 22:58:25 UTC 2009


2009/3/22 Tomasz Torcz:
> Fonts rendered on Ubuntu
> are colorbanded, which make them look blurry...

You are very correct, they are different, but Ubuntu's fontconfig is
not "broken" -- it just has different default settings.  Ubuntu's
default filter is quite different, and some prefer Fedora's.  You can
gain Fedora's method under Ubuntu, actually -- just edit your
fontconfig and apply the lcdlegacy filter (as mentioned in that
Qt-subpixel post I linked above).

But Fedora's only looks good at certain sizes (and with full hinting).
 If you were to increase your fonts to size 10, or use slight hinting,
you'd notice that Fedora has very apparent color-banding that looks
even WORSE than Ubuntu's.  Fedora's default filter only looks good on
small sizes with maximum hinting.

Also, King InuYasha:  you are confusing "hinting" with "subpixel
antialiasing".  They are two very different things.  Microsoft has the
patents for Cleartype (a method for subpixel-antialiasing, or
"smoothing") while Apple owns the patents for the Truetype bytecode
interpreter (which applies "font hinting" to fonts, making them more
aligned with the pixels on the screen).  Hinting is patented by Apple,
yes, but we are not discussing hinting:  we are discussing the
subpixel methods, which are patented by Microsoft.

Anyway, I am not talking about using the same cleartype-style
algorithms that Ubuntu does.  I am talking about using Qt's smoothing
method to reduce color fringing, and how perhaps Fedora could
encourage the Pango project to adopt it, if possible.




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