add todonotes code, WIP

required/latex-lab/latex-lab-tikz.dtx

@@ -55,31 +55,34 @@
 % \section{Introduction}
 %
 % Tagging of \tikzname\ pictures is non trivial. 
-% At first such pictures have a large variaty of purposes
+% 
+% At first such pictures have various purposes:
 % \begin{itemize}
-% \item they can be purely ornamental and decorative, e.g. some page border. This should normally 
+% \item They can be purely ornamental and decorative, e.g. some page border. This should normally 
 % be tagged as artifact. 
-% \item they can show a illustrative figure, similar to png graphics included with
+% \item They can show a illustrative figure, similar to png graphics included with
 % \cs{includegraphics}. This should normally be tagged as a Figure structure with alternative text
-% and the content should be an artifact again.
-% \item they can be meant as normal text. For example the todonotes package uses a
+% and some of the content should perhaps be an artifact again (but not all content,
+% as some PDF viewer ignore empty structures).
+% \item They can be meant as normal text. For example the todonotes package uses a
 % \tikzname\ picture to surround the text in a node with some colored background. 
 % In this case the text should tagged e.g. as an Aside. 
-% \item they can represent a symbol. Then we want to tag a Span or Figure with an /ActualText.
-% \item and naturally there can be all sort of mixtures of these elements, e.g. when a tcolorbox
-% surrounds text with lots of decoration but also includes a title. 
+% \item They can represent a symbol. Then we want to tag as Span or Figure structure element
+% with an /ActualText or
+% perhaps even simply in the stream with a SPAN-BDC with an /ActualText.
+% \item and naturally there can be all sort of mixtures of these elements.
 % \end{itemize}
 % 
-% At second \tikzname\ pictures uses lots of boxes and similar and moves them around 
-% and that makes is not easy
-% to get the tagging right -- at least with pdflatex where one has to pay attention to
+% At second \tikzname\ pictures uses lots of boxes and moves them around 
+% and that makes is not easy to get the tagging right -- 
+% at least with pdflatex where one has to 
 % insert the literals at the right time.
 % 
-% At third at least when the \tikzname\ picture is tagged as Figure one normally should
-% calculate the BBox. This is currently done with some low-level hacking 
-% into the pgf code.
+% At third in some cases, e.g., when the \tikzname\ picture is tagged as Figure, 
+% one normally should calculate the BBox. 
+% This is currently done with some low-level hacking into the pgf code.
 % 
-% The following is a first try to tag at least some of the tikz.
+% The following is a first try to tag at least some of the \tikzname\ pictures.
 % It is incomplete and should be used with care. Resulting structures and contents should
 % be checked!
 % 
@@ -95,15 +98,17 @@
 % The following recipes exist:
 % 
 % \begin{description}
-% \item[figure] This surrounds the picture with a \texttt{Figure} tag and adds a BBox.
+% \item[figure] This is the default receipe. 
+% It surrounds the picture with a \texttt{Figure} tag and adds a BBox.
+% Inside the figure tagging is suspended. 
 % Such a figure should have an alternative text which describes the content. This alternative
 % text can be set with the \texttt{alt} key:
 % \begin{verbatim}
 % \begin{tikzpicture}[alt=A duck]
 % \duck
 % \end{tikzpicture}
 % \end{verbatim}
-% This recipe is meant for meaningful pictures. It is the default setting.
+% This recipe is meant for meaningful pictures. 
 % 
 % \item[text] This surrounds the graphical parts with an artifact MC and activates
 % tagging on node texts. It is meant for small pictures containing text in a node
@@ -123,8 +128,7 @@
 % \end{description}
 % \section{Todos}
 % \begin{enumerate}
-% \item Does it make sense that with figure plug all content is an artifact or should
-% that Figure instead?
+% \item 
 % 
 % \end{enumerate}
 % 
@@ -426,6 +430,39 @@
     },     
  }
 %    \end{macrocode}
+%
+% Handle todonotes. TODO This perhaps should go into firstaid instead
+%    \begin{macrocode}
+\AddToHook{package/todonotes/after}
+{
+\NewSocket{tagsupport/todonotes/todo}{0}
+\NewSocketPlug{tagsupport/todonotes/todo}{default}
+ {\tagpdfsetup{graphic/tagging=text}}
+\AssignSocketPlug{tagsupport/todonotes/todo}{default}
+% 
+
+\renewcommand{\todo}[2][]{%
+  % Needed to output any dangling \item of a noskip section (see #36):
+  \if@inlabel \leavevmode \fi
+  \if@noskipsec \leavevmode \fi
+  \if@todonotes@inlinepar
+    \ifhmode
+      \@bsphack
+      \@todonotes@vmodefalse
+    \else
+      \@savsf\@m
+      \@savsk\z@
+      \@todonotes@vmodetrue      
+    \fi
+     {\UseTaggingSocket{todonotes/todo}\@todo[#1]{#2}}%
+    \@esphack%
+    \if@todonotes@vmode \par \fi
+  \else%    
+    {\UseTaggingSocket{todonotes/todo}\@todo[#1]{#2}}%
+  \fi}
+}  
+%
+%    \end{macrocode}
 %    \begin{macrocode}
 %</package>
 %    \end{macrocode}