[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
RE: [ft] Oversized "O"
RE: [ft] Oversized "O"
Mon, 10 Oct 2005 13:55:34 +0200
I think I have an answer to your question:
- first of all, the behaviour *only* happens when
using the bytecode interpreter. this implies that:
- you're not using the stock FreeType installation
of your Ubuntu distribution :o)
- what's you're seeing is the result of the
instructions located within the font file, this
problem is also very similar to many oddities
exposed by TrueType hinted fonts, like disappearing
diagonals ('z' of Times New Roman Italic), or small
holds in the legs of many "k"s.
- there is little we can do, except if we want to
basically hack the outlines at runtime when we detect
certain glyphs, at certain times, in certain font
files, if only anti-aliased hinting is wanted.
something that I'm not ready to do at the moment.
- note that the overlap doesn't appear in monochrome
rendering mode, because while the same vector outlines
are used in both AA and mono modes, the overlaps are
too small to turn lower or upper mono pixels on.
- When configuring Windows to perform "normal" anti-aliasing
(i.e. not ClearType), you'll notice that small text sizes are
still rendered in monochrome.
I believe that the MS engineers deliberately did this to avoid
the problem described above. They knew it was going to create
confusion, and didn't want users or font developers to change
- When it comes to ClearType, things are different. According
to the presentation file named "Avalon Text" (google for it),
ClearType uses intrisically monochrome bitmap glyphs that are
later composited, then box filtered, then LCD filtered, etc...
that's probably why it doesn't exhibit the overlap problem at
all. It is something you can do with FreeType (it would take
some rather simple changes to libXft), but there are also
many chances that it would infringe on the numerous patents
that MS has on the technology.
More on this later,
- David Turner
- The FreeType Project (www.freetype.org)
> -----Message d'origine-----
> De : address@hidden
> [mailto:address@hidden la
> part de Hanno
> Envoyé : jeudi 6 octobre 2005 18:13
> À : Anton Zemlyanov
> Cc : address@hidden
> Objet : Re: [ft] Oversized "O"
> Anton Zemlyanov schrieb:
> > You should probably know that TT fonts have special "fitting" or
> > "hinting" process that uses byte interpreter to improve the
> quality of
> > small fonts. Unfortunately this works good for monochrome
> fonts only
> By email, you requested a screenshot from a Windows system and as I
> already wrote you there, it seems to me that Windows is not using
> monochrome rendering as you guessed, but subpixel aliasing for this
> font size, as well:
> Windows: http://www.hanno.de/kram/big-o-windows-zoom.png
> Linux/X: http://www.hanno.de/kram/big-o-zoom.png
> > (MS seems to never use anti-aliasing for small font sizes).
> So far, I was under the impression that the "Core Fonts" once freely
> distributed by MS were optimized for screen reading incl.
> good aliasing
> for small font sizes.
> > I found that anti-aliasing is not very beautiful for small
> font sizes
> True, aliased fonts do look a bit "off" in Windows. Freetype's
> subpixel-aliasing is looking much better to me than the one
> used by Windows.
> But my main gripe is the hardware resolution. I wish there were
> higher-resolution desktop TFT displays than the standard 1280x1024
> displays one can buy these days. Some laptops already use 1600x1200
> displays and there, subpixel-aliasing looks really nice. The
> higher the
> dpi resolution of the TFT, the more impressive the effect.
> Best regards,
> Freetype mailing list