showbox in LaTeX
Not a first time when I need to trace a LaTeX layout by digging into the details, and again I’ve spend time remembering how to do it. Fixing the magic in writing.
First, content should be wrapped by a box:
\newsavebox{\xxx}
\savebox{\xxx}{
... content ...
}
Now dump it into the log-file:
\showboxdepth=100 \showboxbreadth=100 \showbox\xxx
The non-obvious thing here is setting showboxdepth and showboxbreadth. For some reason, LaTeX disables box-printing by setting these values to -1. I don’t know where from one could know about it.
Finally, return the box to the document:
\usebox{\xxx}