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Diffstat (limited to 'doc/context/sources/general/manuals/luatex/luatex-math.tex')
| -rw-r--r-- | doc/context/sources/general/manuals/luatex/luatex-math.tex | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/doc/context/sources/general/manuals/luatex/luatex-math.tex b/doc/context/sources/general/manuals/luatex/luatex-math.tex index e5999e72f..b4a2d4b05 100644 --- a/doc/context/sources/general/manuals/luatex/luatex-math.tex +++ b/doc/context/sources/general/manuals/luatex/luatex-math.tex @@ -1242,6 +1242,31 @@ $\Uhextensible width 1pt middle 0 "2194$ font metrics are involved we have a different code path for traditional fonts end \OPENTYPE\ fonts. +Sometimes you might want to act upon the size of a delimiter, something that is +not really possible because of the fact that they are calculated {\em after} most +has been typeset already. In the following example the all|-|zero specification +is the trigger to make a fake box with the last delimiter dimensions and shift. +It's an ugly hack but its relative simple and not intrusive implementation has no +side effects. Any other heuristic solution would not satisfy possible demands +anyway. Here is a rather low level example: + +\startbuffer +\startformula +\Uleft \Udelimiter 5 0 "222B +\frac{\frac{a}{b}}{\frac{c}{d}} +\Uright \Udelimiter 5 0 "222B +\kern-2\fontcharwd\textfont0 "222B +\mathlimop{\Uvextensible \Udelimiter 0 0 0}_1^2 x +\stopformula +\stopbuffer + +\typebuffer + +The last line, by passing zero values, results in a fake operator that has the +dimensions of the previous delimiter. We can then backtrack over the (presumed) +width and the two numbers become limit operators. As said, it's not pretty but it +works. + \subsection{Fractions} \topicindex {math+fractions} |