Help request about hinting dev (Liberation Fonts).

[Caius Carlos CHANCE]

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Hi,

I am currently maintaining Liberation Fonts project. As most of the bugs
that I received were in regard to hinting defects, I would like to ask
about info of font hinting.

As you might heard of, Liberation Fonts were shipped from commercial
fonts manufacturer, Ascender. The deliverable is in .TTF format. The
files were converted into .SFD format and hosted as open source project
on fedorahosted.org.

Unfortunately, along the project runs, there are bug reports of hinting
problem on certain characters. This has raised me the following needs of
info/knowledge:

- - Is there anyone in fedora community who could provide helpful info on
how to manage a high quality hinting?

- - Which free hinting tools are available other than fontforge?

- - Where could I find resources of hinting instructions? Precisely, full
specs of hinting instructions, such as parameter explanation of all
hinting instructions

- - If a CVT table has no comments on each value, do I have to do reverse
engineering and how should I begin?

As Mailhot's previous emails on new font packaging guidelines, he often
let us refer to Dejavu Fonts. I am wondering if I could catch up any of
Dejavu devs who don't mind kindly provide valuable info of hinting?

Thank you very much for reading.

Best Regards,
kaio
- --
Caius Chance, Soft Eng, I18N, Red Hat APAC, cchance AT redhat DOT com
JP (Qual), RHCE, MCSE, CCNA, JLPT4, http://apac.redhat.com/disclaimer
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[Ben Laenen]

On Monday 09 February 2009, Caius "kaio" Chance wrote:
>  - Is there anyone in fedora community who could provide helpful info
>  on how to manage a high quality hinting? 
Well, I'm not from the fedora community, but I've got experience from 
the hinting in the DejaVu fonts.

>  - Which free hinting tools are available other than fontforge?
Tools and documentation are listed at 
http://www.dejavu-fonts.org/wiki/index.php?title=Hinting

About xgridfit: I'm not really a fan of it. I think it may be usable for 
hinting completely new fonts, but I wouldn't start using it on an 
existing font.

My hinting work is basically only done with the help of fontforge and 
gwaterfall.

>  - Where could I find resources of hinting instructions? Precisely,
>  full specs of hinting instructions, such as parameter explanation of
>  all hinting instructions 
You'll have to go through that documentation mentioned on the page 
above. The hinting tutorial on that page which I started myself once 
never really got far, but it can give some idea.

>  - If a CVT table has no comments on each value, do I have to do
>  reverse engineering and how should I begin? 
Yes, you'll have to do some reverse engineering. It takes a considerable 
amount of time, since you basically have to read the hinting of a lot 
of glyphs.

Your goal is to get a table of values you may encounter in normal glyphs 
(and that for each style). 
http://www.dejavu-fonts.org/wiki/index.php?title=Control_Value_Table 
lists it for DejaVu and many fonts have values for the same things in 
their CVT so gives an idea what to expect in Liberation.

There are usually many values in the CVT that don't really matter to you 
if you just want to hint some glyphs.

>  As Mailhot's previous emails on new font packaging guidelines,
> he
>  often let us refer to Dejavu Fonts. I am wondering if I could catch
>  up any of Dejavu devs who don't mind kindly provide valuable info of
>  hinting? 
Here we go then :-)
When I'm online, find me at #dejavu or ##fonts on IRC if you have 
questions.

Ben

[Caius Carlos CHANCE]

Hi Ben,

Ben Laenen さんは書きました:
>  Well, I'm not from the fedora community, but I've got
> experience from 
>  the hinting in the DejaVu fonts. 
Even better! :D

> > - Which free hinting tools are available other than fontforge?
>  
>  Tools and documentation are listed at 
>  http://www.dejavu-fonts.org/wiki/index.php?title=Hinting
>  
>  About xgridfit: I'm not really a fan of it. I think it may be usable for 
>  hinting completely new fonts, but I wouldn't start using it on an 
>  existing font. 
Could I know the reason why?

>  My hinting work is basically only done with the help of fontforge and
>
>  gwaterfall. 
If you are available, it would be fantastic if you briefly tell me in 10 
-15 steps?

> > - Where could I find resources of hinting instructions?
> Precisely,
> > full specs of hinting instructions, such as parameter explanation of
> > all hinting instructions 
Thomas Sailer gave me few valuable URLs just now, too:

http://developer.apple.com/textfonts/TTRefMan/RM05/Chap5.html

> > - If a CVT table has no comments on each value, do I have to do
> > reverse engineering and how should I begin?
>  
>  Yes, you'll have to do some reverse engineering. It takes a considerable 
>  amount of time, since you basically have to read the hinting of a lot 
>  of glyphs.
>  
>  Your goal is to get a table of values you may encounter in normal glyphs 
>  (and that for each style). 
>  http://www.dejavu-fonts.org/wiki/index.php?title=Control_Value_Table 
>  lists it for DejaVu and many fonts have values for the same things in 
>  their CVT so gives an idea what to expect in Liberation. 
Good to confirm that with you, so I could start the reverse engineering.

>  Here we go then :-)
>  When I'm online, find me at #dejavu or ##fonts on IRC if you have 
>  questions. 
Thanks for your kind offer. :)

Best Regards,
kaio.

[Ben Laenen]

On Monday 09 February 2009, Caius Chance wrote:
>  > Tools and documentation are listed at
>  > http://www.dejavu-fonts.org/wiki/index.php?title=Hinting
>  >
>  > About xgridfit: I'm not really a fan of it. I think it may be
>  > usable for hinting completely new fonts, but I wouldn't start using
>  > it on an existing font.
>
>  Could I know the reason why? 
Basically because it never convinced me it actually would make things 
easier and wouldn't just add an extra layer of complexity and 
compatibility issues.

>  > My hinting work is basically only done with the help of
> fontforge
>  > and gwaterfall.
>
>  If you are available, it would be fantastic if you briefly tell me in
>  10 -15 steps? 
What do you want to know exactly?

Ben

[Caius Carlos CHANCE]

Ben Laenen さんは書きました:
>  On Monday 09 February 2009, Caius Chance wrote:
> >> My hinting work is basically only done with the help of fontforge
> >> and gwaterfall.
> > If you are available, it would be fantastic if you briefly tell me in
> > 10 -15 steps?
>  
>  What do you want to know exactly? 
My previous experience was trying to fix hinting problems, I went into 
hinting instruction window of a glyph. Then looked at the hinting 
instructions and see if there are any problems.

I am wondering about what extra you have done to a font, rather that 
just modifying hinting instructions.

Thanks a lot. :)

kaio

[Ben Laenen]

On Monday 09 February 2009, Caius Chance wrote:
>  Ben Laenen さんは書きました:
>  > On Monday 09 February 2009, Caius Chance wrote:
>  >>> My hinting work is basically only done with the help of fontforge
>  >>> and gwaterfall.
>  >>
>  >> If you are available, it would be fantastic if you briefly tell me
>  >> in 10 -15 steps?
>  >
>  > What do you want to know exactly?
>
>  My previous experience was trying to fix hinting problems, I went
>  into hinting instruction window of a glyph. Then looked at the
>  hinting instructions and see if there are any problems.
>
>  I am wondering about what extra you have done to a font, rather that
>  just modifying hinting instructions. 
You want a list of everything I've done with a font so far? :-p

In respect to hinting in DejaVu the only things you can really do is 
editing existing instructions and creating new ones for the new glyphs. 
Over the time CVT values were added, the fpgm table was altered etc.

After editing it's just a matter of testing it out -- you can do that 
within FontForge itself (grid fit), and then check in gwaterfall if 
there's not a weird problem at some size.

Only the first person who wants to work on the hinting needs to do some 
work to know what the important CVT values are, and that's basically 
reading the existing instructions and write down which values are used 
where. It's usually pretty straightforward (if it moves a point on the 
right side of the stem of "I" horizontally when the reference point 0 
is a point on the left side of that stem, then you know it's the 
horizontal stem width). But that requires understanding of the 
instructions of course (I don't know how much you know about it, 
http://www.dejavu-fonts.org/wiki/index.php?title=Hinting_tutorial/Example... 
should give you the real basics if you're completely new).

For hinting that's it really. I don't know what more you're expecting?

[Caius Carlos CHANCE]

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Ben Laenen wrote:
>  For hinting that's it really. I don't know what more
> you're expecting? 
That's what I am expecting. Thanks very much, Ben. :)

Best Regards,
kaio


- --
Caius Chance, Soft Eng, I18N, Red Hat APAC, cchance AT redhat DOT com
JP (Qual), RHCE, MCSE, CCNA, JLPT4, http://apac.redhat.com/disclaimer
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