Boundingbox for each Letter using lua code (follow-up question)

Question

This is a follow-up question regarding topskip's answer:

topskip's code works very well, even for complex documents (containing tables, pagination, footnotes etc.), nevertheless, as the following screenshot demonstrates, some of these elements do not get boxed.

Question: Why isn't every letter boxed? What's wrong?

The screenshot is part of the result produced by this MWE (demo thesis, taken from berkeley):

%% thesis.tex 2014/04/11
% Source: https://math.berkeley.edu/~vojta/thesis/
% Integrated into one single file, extended using topskip's luaCharBox-code
%
\documentclass{ucbthesis}
\usepackage{luacode,luatexbase,microtype,blindtext}
\begin{luacode*}
local GLYPH_ID = node.id("glyph")

-- head is a linked list (next/prev entries pointing to the next node)
-- parent it the surrounding h/vbox
function showcharbox(head,parent)
    while head do
        if head.id == 0 or head.id == 1 then
            -- a hbox/vbox
            showcharbox(head.list,head)
        elseif head.id == GLYPH_ID then
            r = node.new("rule")
            r.width  = head.width
            r.height = head.height
            r.depth  = head.depth

            -- replace the glyph by
            -- the rule by changing the
            -- pointers of the next/prev
            -- entries of the rule node
            if not head.prev then
                -- first glyph in a list
                parent.list = r
            else
                head.prev.next = r
            end

            head.next.prev = r
            r.prev = head.prev
            r.next = head.next

            -- now the glyph points to
            -- nowhere and we should remove
            -- it from the memory
            node.free(head)

            head = r
        end
        head = head.next
    end
    return true
end

luatexbase.add_to_callback("post_linebreak_filter",showcharbox,"showcharbox")
\end{luacode*}

\newtheorem{theorem}{Jibberish}

\begin{document}
\pagestyle{headings}

That's fine until footnote:\footnote{Davidson witting and grammatic.}

\begin{theorem}
    \tolerance=10000\hbadness=10000
    This does not work.
\end{theorem}

That's fine again: Wash, Doff, and Algorithm.

\begin{itemize}
    \item Items work partially.
    \item Salutary.  Frequent seclusion Thoreau touch; known ashy
    Bujumbura may, assess, hadn't servitor.  Wash, Doff, and Algorithm.
\end{itemize}   
\end{document}

Note: When using book, article, scrbook or scrartcl instead of ucbthesis class the page number does not get boxed.

Bonus-MWE

It demonstrates the problem regarding the figure caption:

\documentclass[a4paper,10pt]{article}

\usepackage{luacode,luatexbase,microtype,blindtext}
\begin{luacode*}
local GLYPH_ID = node.id("glyph")

-- head is a linked list (next/prev entries pointing to the next node)
-- parent it the surrounding h/vbox
function showcharbox(head,parent)
    while head do
        if head.id == 0 or head.id == 1 then
            -- a hbox/vbox
            showcharbox(head.list,head)
        elseif head.id == GLYPH_ID then
            r = node.new("rule")
            r.width  = head.width
            r.height = head.height
            r.depth  = head.depth

            -- replace the glyph by
            -- the rule by changing the
            -- pointers of the next/prev
            -- entries of the rule node
            if head.prev then
                head.prev.next = r
            else
                -- first glyph in a list
                parent.list = r
            end

            if head.next then
                head.next.prev = r
            end

            r.prev = head.prev
            r.next = head.next

            -- now the glyph points to
            -- nowhere and we should remove
            -- it from the memory
            node.free(head)

            head = r
        end
        head = head.next
    end
    return true
end

luatexbase.add_to_callback("post_linebreak_filter",showcharbox,"showcharbox")
\end{luacode*}

\usepackage{tikz}
\usepackage{blindtext}
\begin{document}

\blindtext

\begin{figure}[htb]
\centering
\begin{tikzpicture}
\edef\sizetape{1cm}
\tikzstyle{tmtape}=[draw,minimum size=\sizetape]
\node [tmtape] (input) {blabla};
\end{tikzpicture}
\caption{Hello World!}
\end{figure}

\blindtext

\end{document}

Note: The page number isn't boxed any more, too.

@topskip Sorry, my intention was to take a somewhat comp[ete|lex] document from stock. I reduced the mWE. — lAtExFaN, Sep 15 '17 at 16:09
@topskip please have a look on the Bonus MWE I added: It should demonstrate the problem I mentioned regarding the figure caption. Thx a lot! — lAtExFaN, Sep 16 '17 at 19:57

topskip · Accepted Answer · 2023-05-09T08:28:07.833

There is a bug in the code which causes the Lua loop to break. I have tried to assign r to head.next.prev even if head has no next pointer. The fix is to guard the assignment:

if head.next then
     head.next.prev = r
end

So the code is:

%% thesis.tex 2014/04/11
% Source: https://math.berkeley.edu/~vojta/thesis/
% Integrated into one single file, extended using topskip's luaCharBox-code
%
\documentclass{ucbthesis}
\usepackage{luacode,luatexbase,microtype,blindtext}
\begin{luacode*}
local GLYPH_ID = node.id("glyph")
-- head is a linked list (next/prev entries pointing to the next node)
-- parent it the surrounding h/vbox
function showcharbox(head,parent)
    while head do
        if head.id == 0 or head.id == 1 then
            -- a hbox/vbox
            showcharbox(head.list,head)
        elseif head.id == GLYPH_ID then
            r = node.new("rule")
            r.width  = head.width
            r.height = head.height
            r.depth  = head.depth
        -- replace the glyph by
        -- the rule by changing the
        -- pointers of the next/prev
        -- entries of the rule node
        if head.prev then
            head.prev.next = r
        else
            -- first glyph in a list
            parent.list = r
        end

        if head.next then
          head.next.prev = r
        end

        r.prev = head.prev
        r.next = head.next

        -- now the glyph points to
        -- nowhere and we should remove
        -- it from the memory
        node.free(head)

        head = r
    end
    head = head.next
end
return true

end
luatexbase.add_to_callback("post_linebreak_filter",showcharbox,"showcharbox")
\end{luacode*}
\newtheorem{theorem}{Jibberish}
\begin{document}
\pagestyle{headings}
That's fine until footnote:\footnote{Davidson witting and grammatic.}
\begin{theorem}
    \tolerance=10000\hbadness=10000
    This does not work.
\end{theorem}
That's fine again: Wash, Doff, and Algorithm.
\begin{itemize}
    \item Items work partially.
    \item Salutary.  Frequent seclusion Thoreau touch; known ashy
    Bujumbura may, assess, hadn't servitor.  Wash, Doff, and Algorithm.
\end{itemize}
\end{document}

To answer the bonus question: I don't know why the caption does not call the post_linebreak_filter, perhaps it is not broken into lines?!?

You can use the package atbegshi to get the complete contents of the page:

\documentclass[a4paper,10pt]{article}
\usepackage{luacode,atbegshi}
\begin{luacode*}
local GLYPH_ID = node.id("glyph")
-- head is a linked list (next/prev entries pointing to the next node)
-- parent it the surrounding h/vbox
function showcharbox(head,parent)
    while head do
        if head.id == 0 or head.id == 1 then
            -- a hbox/vbox
            showcharbox(head.list,head)
        elseif head.id == GLYPH_ID then
            r = node.new("rule")
            r.width  = head.width
            r.height = head.height
            r.depth  = head.depth
        -- replace the glyph by
        -- the rule by changing the
        -- pointers of the next/prev
        -- entries of the rule node
        if head.prev then
            head.prev.next = r
        else
            -- first glyph in a list
            parent.list = r
        end

        if head.next then
          head.next.prev = r
        end

        r.prev = head.prev
        r.next = head.next

        -- now the glyph points to
        -- nowhere and we should remove
        -- it from the memory
        node.free(head)

        head = r
    end
    head = head.next
end
return true

end
\end{luacode*}
\AtBeginShipout {\directlua{showcharbox(tex.box["AtBeginShipoutBox"])}}%
\begin{document}
\begin{figure}
\fbox{x}
\caption{Hello World!}
\end{figure}
\end{document}

BTW: please make a M WE next time. The document doesn't need microtype nor tikz to show the problem. Even blindtext is not needed.

Boundingbox for each Letter using lua code (follow-up question)

Bonus-MWE

1 Answers1

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