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authorNorbert Preining <norbert@preining.info>2021-02-15 03:01:20 +0000
committerNorbert Preining <norbert@preining.info>2021-02-15 03:01:20 +0000
commit8fb1cfd3d240ef62d78c2320bd90f8f07b7916fa (patch)
tree402ab28aa933f0b5a42c2a1d9646717340fae50e /systems/doc/luatex/luatex-math.tex
parent8c6ca435b3bc584eb3efe8e52417fb989e677789 (diff)
CTAN sync 202102150301
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diff --git a/systems/doc/luatex/luatex-math.tex b/systems/doc/luatex/luatex-math.tex
index e5999e72fd..89c0836ba7 100644
--- a/systems/doc/luatex/luatex-math.tex
+++ b/systems/doc/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}
@@ -1306,6 +1331,9 @@ For Latin Modern the result looks as follows:
\stoptabulate
\stop
+The keyword \type {norule} will hide the rule with the above variants while
+keeping the rule related spacing.
+
\subsection {Delimiters: \type{\Uleft}, \prm {Umiddle} and \prm {Uright}}
\topicindex {math+delimiters}