[NTG-context] ConTeXt update

Hans Hagen pragma at wxs.nl
Sun Feb 21 18:00:59 CET 2010

On 21-2-2010 17:44, Mojca Miklavec wrote:
> On Sun, Feb 21, 2010 at 15:11, Troy Henderson wrote:
>> Mojca,
>> This is great news.  Perhaps this page should be updated
>> http://wiki.contextgarden.net/Lucida
> Not yet. It needs to start working in the first place. Math is still
> pretty broken (some basic commands work, but all the rest doesn't).
>> Also, I've noted (as previously stated in another feed) that there
>> appears to be some kerning issues in the math as well.  For example,
>> $\sin(x)\cos(y)$ have the "n" in "sin" and the "s" in "cos" too close
>> to the following "(".
> You are talking about MKIV, right (since I don't even get parenthesis
> in MKII, but harpoons instead; I know the reason, I just didn't write
> the cure yet).

you need a more recen tversion then i guess ... older attempts still 
used the traditional lucida math vectors

> Bold math is a separate issue that I have never really understood.
> There is \mathbf, \bf, \bfm, \bfmath, switching the complete typeface
> to a bolder variant etc.

> I really really really really wish that somebody would explain and
> document how bold math is supposed to work (there are several variants
> - some should also influence operators and some should only influence
> numbers).

there is some about it in the mk.pdf document (math chapter)

this is what i think happened ...

- in math there are cases where you use bold or sans or whatever letters

- in traditional tex, this was dealt with by assigning bold, sans .. 
fonts to families (16 families max with already some taken by symbols 
and extensible characters)

- so, there we're taking of a mix of regular (non bold) math with an 
occasional bold letter; in plain that could be achieved by \bf which 
simply does a family change

- in addition, for instance for titles, full bold math is needed but for 
that one needs all math symbols etc to be available

- also, one needs to make sure that all families then are associated 
with bold shapes

- however, as tex only applies the fonts related to families at the end 
of reading a formula, mid time reassigning fonts to families will not work

- so, we end up with (1) mixed normal/bold/etc, (2) full bold, (3) 
compromises due to lack of families and fonts

- in unicode however, the bold etc letters (and a few symbols) have 
their oen place and  we have several alphabets

- this means that a proper math font now has all relevant symbols, 
letters (in multiple lphabets) in one set

- so, as the occasional bold character now is no longer associated with 
a family, we can d with two families: regular (with also a bold 
alphabet) and bold and this iexactly what context mkiv does

- now, as users are unlikely to use the proper unicode bold letters, we 
still need to support switching to (say) a bold alphabet and (again in 
mkiv) this means some sort of remapping on the fly and no family 
trickery any more

So, to summarize, mkiv:

(1) implements unicode math
(2) for traditional tex fonts it makes virtual math unicode fonts
(3) supports traditional input using wel known font switching commands
(4) has an implementation that deviates from the traditional way (but in 
my opinion is more modern)

Of course, in the process we need to do a lot of testing esp because we 
cannot rely on other sources (to many errors so we started from 
scratch). Also, all math related data is collected in tables in such a 
way that we can at some point add more advanced support, like domain 
specific rendering (and symbols) which is currently seldom part of tex 
math implementations.

Feel free to ask for all you have been missing in math so far. We're not 
that bound to traditional approaches.


                                           Hans Hagen | PRAGMA ADE
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      tel: 038 477 53 69 | fax: 038 477 53 74 | www.pragma-ade.com
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