# [NTG-context] \right| spacing issue

Hans Hagen pragma at wxs.nl
Mon May 9 22:31:18 CEST 2016

On 5/9/2016 7:47 PM, Weber, Matthias wrote:
> Dear All,
>
> the right hand side moves the Y into the |.
> This used to look ok in older versions of mkiv & mkii.
>
> \starttext
> \startformula
>  |X\times Y|= \left| X\times Y\right|
> \stopformula
> \stoptext

This is a side effect of extreme italics in latin modern. These are
are always added and sometimes compensated when not needed, while in
opentype math those corrections are only added in character sequences
(sort of) and not in constructs (which left/right are).

Fixing thei s lm wil make other fonts behave bad so we have a chicken
egg problem there. Best is to patch lm fonts to behave more like other
fonts (i might provide that as pseudo feature).

\starttext

\showglyphs

\startbuffer
\startformula
|X\times Y| = \left| X\times Y \right| = \left( X\times Y \right) =
\left( {X\over Y} \right)
\stopformula
\startformula
|x\times y| = \left| x\times y \right| = \left( x\times y \right) =
\left( {x\over y} \right)
\stopformula
\stopbuffer

\getbuffer
\switchtobodyfont[cambria] \getbuffer
\switchtobodyfont[pagella] \getbuffer

\stoptext

the lm italic correction for Y is some 40% vs 5% for cambria.

(one can argue that for normal size fences italic correction can be
added but for that we need proof from the specification (ok, we can make
that an option in the engine if really needed)

Hans

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