Re: [ft] Regression in rendering quality with subpixel antialiasing

[Bernd Schubert]

Hello David,

thanks a lot for your long explanation! It is really helpfull.

> thank you for providing me with the additionnal screenshot, they were
> exactly what I needed (the ones provided with the bug-report weren't
> enough informative).
>
> The short answer to your question is that, to get rid of the bluriness,
> you should select a different hinting mode (medium or strong/full in
> your font preferences dialog), which is rather easy.

usually I already switched to full hinting mode, I just set the slight mode 
for the screenshots.

>
> To get the exact *exact* same results than before, you will also have to
> re-enable the patent-infringing bytecode interpreter, if your build of
> FreeType didn't do that.
>
> However, I consider doing the latter  to be a rather bad thing, or even in
> the case of Debian, a grave political mistake since I believe it goes
> completely against the goals of Debian; And I never quite understood why
> the FreeType deb package always had the bytecode enabled by default in this
> distribution (or in Ubuntu); the first thing I do when I install one of
> them is to re-install a default build of FreeType.

Psst, if Steve reads this it really might happen. Then, after the update to 
Etch about 40 group members will complain about blurry fonts and in end I 
have to regularily recompile another package... (though probably I won't be 
in this group anymore that time).

[...]

> - however, the "before" screenshot also show that you used a build of
> 2.1.10 with the patent-infringing bytecode interpreter *enabled*. In this
> specific case, 2.1.10 and previous versions simply ignore the hinting mode
> you provided and always rendered the glyphs with the bytecode interpreter
>
>   which I considered a bit stupid, since this denies any user preferences.
>
> - in 2.2.1, the font engine was slightly modified, first to improve the
>   "light" hinting mode results, but also to force FreeType to not use the
>   bytecode interpreter if this mode was selected.

Ah, this explains a lot.

I have uploaded a another screenshot of my console font will full subpixel 
hinting, now there's really absolutely no difference to 2.1.10.

http://www.pci.uni-heidelberg.de/tc/usr/bernd/downloads/freetype-snapshots/2-old.png
http://www.pci.uni-heidelberg.de/tc/usr/bernd/downloads/freetype-snapshots/2-new_full_sub.png

However, I already wrote in my first mail, that full subpixel hinting doesn't 
entirely help e.g. with OpenOffice. I have uploaded two new shots.

http://www.pci.uni-heidelberg.de/tc/usr/bernd/downloads/freetype-snapshots/3-old_full_sub.png
http://www.pci.uni-heidelberg.de/tc/usr/bernd/downloads/freetype-snapshots/3-new_full_sub.png

I think you can see that 3-old_full_sub.png looks better than 
3-new_full_sub.png. Do you have an idea whats going on?


Thanks,
Bernd