Re: [Freetype] Re: To Hint or Not To Hint

[David Turner]

Hello Jon,

Jon Harrop wrote:
> > As you can see when hinting is on fonts look real bad. Anyone got any
> > idea what may be the problem?
>
>
> I am not a fan of hinting myself but I must say that the hinted version of 
> your text actually looks better to me. I would class your example as 
> intermediate size because the resolution is small enough that pixel 
> boundaries are visible but large enough that each glyph fills more than 5 
> pixels (which is really the minimum size for a readable font, IMHO).
I think you missed what he was really complaining about: the letters are
slightly distorted compared to their "original" hinted shape (e.g. the 'e'),
which is why it found it bad.

> The example you give is much better than other examples that I have seen, 
> particularly on my own computer (KDE v 2.2.2 with FreeType 2 v 2.1.2) where 
> hinting runs glyphs together, alters the final size of text and can 
> considerably change the optical weighting of a font.
FT 2.1.2 with or without the bytecode interpreter enabled ? With TrueType or
Postscript fonts ? This can make huge differences in rendering, much more
important than the distortions described here...

And *any* kind of hinting (native, auto, wathever) will change the final size of
text, unless you're performing WYSIWIG rendering (which most applications don't
do for complexity reasons)

> Just out of curiosity - do you guys think that automatic hinting could work 
> on general vector graphics?
It could work, but the improvements might not be very noticeable (or it could
even make things wrong). The main reasons behing this are the following facts:

 - for arbitrary shapes, you cannot define "blue zones" to define important
   alignment zones with specific behaviour, these are very specific to
   typography

  - hinting works well with fonts because glyphs are made of lots of horizontal
    and/or vertical stems with similar widths/heights. This is used by the
    hinting algorithms to decide that in some cases, a width of 1.5 pixels
    should be snapped to 1 pixel, 2 pixel, or left untouched, depending on
    context (like character pixel size which determines the size of the
    "main" stem width, etc...). You can't use such information for general
    shapes.

Hope this helps,

- David Turner
- The FreeType Project  (www.freetype.org)