On Fri, Sep 1, 2017 at 7:49 PM, Hans Hagen <pragma@wxs.nl> wrote:
On 9/1/2017 1:56 PM, Mikael P. Sundqvist wrote:
Hi,

I stumbled upon this (see the attached file for the result):

%%% Test file
\setupbodyfont[10pt]
\starttext
\startTEXpage[offset=10pt]
\type{\tbinom{n}{k}}: $\tbinom{n}{k}$, (does not look good, the vertical space between $n$ and $k$ is too big) \par
\type{\binom{n}{k}}: $\binom{n}{k}$ (looks fine to me)\par
\type{\dbinom{n}{k}}: $\dbinom{n}{k}$ (does not look good, too big parenthesis, even for displayed formulas).\par
\stopTEXpage
\stoptext
%%% End of test file

I think something should be changed to get the binomial coefficients to look better. In particular I am concerned about the rather big parenthesis in displaystyle (and not so much about the vertical space issue in \tbinom).

/Mikael

PS The result looked better if I used the lucida fonts, if that helps.
This is indeed font dependent. These binoms use a low level tex primitive that uses a threshold for steps and that one is part of the math parameters of a font and these are not that good for lm. As I'm looking into some other low level side effect I was in the mood for a configuration option for \setupmathfractions.

So, in the next beta you can get the effects iof the attached:

- relate the threshold to the bodyfont size
- use normal left/right fences instead

fwiw, cambria and pagella look better too. Upto you to wikify it.

Hans

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                                          Hans Hagen | PRAGMA ADE
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Thank you very much, I'm looking forward to the next beta, and I will try to wikify it when I have tried it out. Also lucida looks better than latin modern does at the moment.

I am a bit confused about the different versions. I would have guessed that there was \tbinom and \dbinom and that \binom used one of them depending on if one is in text mode or in display mode (just as I would expect \frac to behave like \tfrac in text mode and \dfrac in display mode). But \tbinom looks very different from \binom in text mode (with more vertical space).  Is this on purpose? Have I missed something?

/Mikael