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-rw-r--r--macros/latex-dev/required/latex-lab/latex-lab-amsmath.dtx90
1 files changed, 85 insertions, 5 deletions
diff --git a/macros/latex-dev/required/latex-lab/latex-lab-amsmath.dtx b/macros/latex-dev/required/latex-lab/latex-lab-amsmath.dtx
index e1f95730fa..c50a40eedd 100644
--- a/macros/latex-dev/required/latex-lab/latex-lab-amsmath.dtx
+++ b/macros/latex-dev/required/latex-lab/latex-lab-amsmath.dtx
@@ -2,7 +2,7 @@
%
%% File: latex-lab-amsmath.dtx
%
-% Copyright (C) 2022,2023 The LaTeX Project
+% Copyright (C) 2022-2024 The LaTeX Project
%
% It may be distributed and/or modified under the conditions of the
% LaTeX Project Public License (LPPL), either version 1.3c of this
@@ -66,7 +66,7 @@
% \subsection{File declaration}
% \begin{macrocode}
\ProvidesFile{latex-lab-amsmath.ltx}
- [2023-01-05 v0.1a amsmath adaptions]
+ [2024-02-12 v0.1b amsmath adaptions]
% \end{macrocode}
% \subsection{Tagpdf support}
% To make the code independent from tagging being loaded and active
@@ -90,7 +90,11 @@
\def\intertext##1{%
\ifvmode\else\\\@empty\fi
\noalign{%
- \penalty\postdisplaypenalty\vskip\belowdisplayskip
+% \end{macrocode}
+% we have to flip the sign and use a negative \cs{belowdisplayskip}
+% as we flipped the sign at the outside.
+% \begin{macrocode}
+ \penalty\postdisplaypenalty\vskip-\belowdisplayskip
\vbox{
% \end{macrocode}
% Stop tagging when measuring:
@@ -105,9 +109,13 @@
% \begin{macrocode}
\tag_mc_end_push:
% \end{macrocode}
-% We are already in a par so we change now to Span:
+% We are already in a par so we change now to text:
+% \begin{macrocode}
+ \tagpdfsetup{paratag=P}%
+% \end{macrocode}
+% TODO why \cs{tagpdfparaOn} needed?
% \begin{macrocode}
- \tagpdfsetup{paratag=Span}%
+ \tagpdfparaOn
\noindent\ignorespaces##1\par
% \end{macrocode}
% Restart the MC
@@ -119,6 +127,78 @@
}
% \end{macrocode}
%
+% \subsection{\cs{text}}
+%
+% The \cs{text} command uses \cs{mathchoice} which \enquote{typesets} the argument
+% four times. This makes it quite problematic for tagging. Without precautions
+% structure objects would be created four times and would get MC-chunks as kids
+% that doesn't really exist. amsmath contains a switch that allows to execute code
+% only in the first (displaymath) branch, but that isn't usable here. At first because
+% we don't know if the first branch creates the same structure as the one that is
+% actually used. At second because the engines executes some commands like \cs{label}
+% and \cs{pdfannot} only at shipout from the branch that really was used. So we would
+% get structure data from one \cs{mathchoice}-branch and MC-labels and links from another
+% one and that gets very messy.
+%
+% We therefore have to avoid that tagging is active in unused branches. In pdflatex it
+% is not possible to detect the mathstyle before, so we use a label. With lualatex is
+% is possible to redefine \cs{text} not to use \cs{mathchoice}
+%
+% \begin{macrocode}
+\AddToHook{package/amstext/after}
+ {
+% \end{macrocode}
+% currently amsmath is loaded in a begindocument hook, so this
+% test is fine. If amstext is loaded earlier (in the kernel), this needs perhaps a change.
+% \begin{macrocode}
+ \tag_if_active:T
+ {
+ \sys_if_engine_luatex:TF
+ {
+ \def\text@#1{{%
+ \ifcase\mathstyle
+ \hbox{{#1}}\or
+ \hbox{{#1}}\or
+ \hbox{{#1}}\or
+ \hbox{{#1}}\or
+ \hbox{{\let\f@size\sf@size\selectfont#1}}\or
+ \hbox{{\let\f@size\sf@size\selectfont#1}}\or
+ \hbox{{\let\f@size\ssf@size\selectfont#1}}\or
+ \hbox{{\let\f@size\ssf@size\selectfont#1}}\or
+ \ERROR
+ \fi
+ \check@mathfonts
+ }}
+ }
+ {
+ \def\text@#1
+ {{
+ \int_gincr:N\g__math_mathchoice_int
+ \tag_stop:
+ \mathchoice
+ {
+ \@@_tag_if_mathstyle:en{mathchoice-\int_use:N\g__math_mathchoice_int}{0}
+ \textdef@\displaystyle\f@size{#1}
+ }
+ {
+ \@@_tag_if_mathstyle:en{mathchoice-\int_use:N\g__math_mathchoice_int}{2}
+ \textdef@\textstyle\f@size{\firstchoice@false #1}
+ }
+ {
+ \@@_tag_if_mathstyle:en{mathchoice-\int_use:N\g__math_mathchoice_int}{4}
+ \textdef@\textstyle\sf@size{\firstchoice@false #1}
+ }
+ {
+ \@@_tag_if_mathstyle:en{mathchoice-\int_use:N\g__math_mathchoice_int}{6}
+ \textdef@\textstyle \ssf@size{\firstchoice@false #1}
+ }
+ \check@mathfonts
+ }}
+ }
+ }
+ }
+% \end{macrocode}
+%
% \begin{macrocode}
\ExplSyntaxOff
% \end{macrocode}