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Re: Bug#216667: Freetype patent issues

On Fri, Jan 23, 2004 at 08:08:03AM +0000, Brian M. Carlson wrote:
> > patch (030-bytecode-interpreter.diff), I suspect this patch still remains from
> > the 1.0 freetype series, when this and other patches were used to supply an
> > unpatented bytecode interpreter. According to the freetype site, this would now
> > cause freetype to fall under the patents granted to Apple, just like the 1.0
> > series. Disabling this patch would make freetype in debian patent-free again
> > (from my point of view), while drasticly improving AA fonts in Debian (and
> > derivatives alike). A bug [2] has already been submitted to do this some time
> > ago.

> That being said, the maintainer should get a move on and remove the
> patch so that the fonts look right.

Things are not as simple as they seem, and turning off the bytecode
interpreter would bring a whole different set of bug reports,
especially with some popular CJK fonts becoming totally distorted
because such fonts use TrueType instructions to resize each stroke.
FreeType developers had added a patent-free bytecode interpreter,
but while it works well with CJK fonts, it screws up hand-tuned
fonts like Arial.

Font esthetics is a very subjective thing.  I don't buy the claim that
disabling the bytecode interpreter would "drasticly improving AA fonts in
Debian" simply because some fonts are broken without it.  Having said that,
I do agree that many fonts are not professionally tuned and look worse with
bytecode-instructed hinting turned on.  I have tried enabling this patch or
disabling that patch, and each time a different group of people will file
bug reports requesting me to revert the changes.  Perhaps I'm biased (I'm
Chinese), but patent issue aside, "unrecognizable distorted CJK fonts" is
a more serious bug than "font esthetics".

I just did some experiments, and it seems that the "prettier" version
(http://descent.netsplit.com/~scott/fonts-upstream.png) was rendered with
FreeType's "autohinting" on.  In that case, I suggest modifying
/etc/fonts/local.conf and uncomment the following:

<!-- Uncomment below to enable the freetype autohinter module -->
  <match target="font">
    <edit name="autohint" mode="assign">

That should make Trebuchet MS look better.  :-)

Branden Robison and others suggested splitting the libfreetype6 package into
two: libfreetype6 and libfreetype6-bytecode, and I began experimenting with
it a while ago, but then sensed some potential traps if not done properly.

Meanwhile, FreeType developers and others are researching ways to solve
the current dilemma and improve the rendering quality of both CJK and
Western fonts, and as their patches become mature, they will be merged
into the Debian FreeType package.

Best regards,


Anthony Fok Tung-Ling
ThizLinux Laboratory   <anthony@thizlinux.com> http://www.thizlinux.com/
Debian Chinese Project <foka@debian.org>       http://www.debian.org/intl/zh/
Come visit Our Lady of Victory Camp!           http://www.olvc.ab.ca/

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