How to measure the vertical space that was typeset without placing it into an environment?

Question

I would like to achieve automatic clearing of a {floatingfigure} at the beginning of a new \section for texts automatically created by Pandoc. For this to work, I am in need of a way to measure the vertical space that was typeset by LaTeX since placing the {floatingfigure}.

I tried out the placeins package to no effect.

The ideal solution would involve placing a starting marker. An environment or any other block/braced/bracketed structure should not be used as the text that follows the {floatingfigure} is generally unknown. Everything needs to be implemented by renewing commands and environments in the preamble.

Should a second starting marker follow upon a first starting marker without taking a measurement, than the vertical measurement should be reset to 0pt.

Here is a minimum working example. I have placed comments from where to where I would like to measure.

\documentclass{article}
\usepackage{mwe}

\makeatletter
\def\maxwidth{\ifdim\Gin@nat@width>\linewidth\linewidth
\else\Gin@nat@width\fi}
\makeatother
\let\Oldincludegraphics\includegraphics
\renewcommand{\includegraphics}[1]{\Oldincludegraphics[width=\maxwidth]{#1}}

\setlength{\parindent}{0pt}

\usepackage{calc}
\newlength\imgheight

\usepackage{floatflt}
\renewenvironment{description}{%
    \renewcommand{\includegraphics}[1]{\vspace{-1ex}\Oldincludegraphics[width=4cm]{##1}}
    \renewcommand{\item}[1][]{
        \settototalheight\imgheight{##1}%
        \global\imgheight=\imgheight%
        ##1%
        \end{floatingfigure}%
        % I would like to measure vertical space from here...
        }%
    \hspace{0pt}%
    \begin{floatingfigure}[l]{4cm}}%
    {}
% end preamble.tex

\begin{document}
\begin{description}
\itemsep1pt\parskip0pt\parsep0pt
\item[\includegraphics{example-image-a}]
Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Etiam lobortis facilisis
sem. Nullam nec mi et neque pharetra sollicitudin.
\end{description}

% ... to here.
\vspace{\dimexpr\imgheight-3\baselineskip}
\section{Section title}
\begin{description}
\itemsep1pt\parskip0pt\parsep0pt
\item[\includegraphics{example-image-b}]
Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Etiam lobortis facilisis
sem. Nullam nec mi et neque pharetra sollicitudin.
\end{description}

\blindtext
\end{document}

In below document, the first paragraph is too short to wrap completely around floatingfigure A. Hence, I would like to achieve automatic floatingfigure clearing at the beginning of a new section or a new floatingfigure. Right now, I have done it manually by adding \vspace{\dimexpr\imgheight-3\baselineskip}.

Answer 1

I have found a solution based on \pagetotal, thanks to the comment of @karlkoeller. In below example, automatic clearing of a wrapped floatingfigure is achieved both at the beginning of a new floatingfigure or a \section.

This is also a solution to the question: How do I clear a floatfig?

\documentclass{article}
\usepackage{mwe}

\makeatletter
\def\maxwidth{\ifdim\Gin@nat@width>\linewidth\linewidth
\else\Gin@nat@width\fi}
\makeatother
\let\Oldincludegraphics\includegraphics
\renewcommand{\includegraphics}[1]{\Oldincludegraphics[width=\maxwidth]{#1}}

\setlength{\parindent}{0pt}

% begin preamble.tex   
\usepackage{calc}
\newlength\vimgflt
\newlength\vposflt
\newlength\vtypesetflt
\newlength\vspaceflt

\usepackage{floatflt}
\renewenvironment{description}{%
    \renewcommand{\includegraphics}[1]{\vspace{-1ex}\Oldincludegraphics[width=4cm]{##1}}
    \renewcommand{\item}[1][]{
        \settototalheight\vimgflt{##1}%
        \global\vimgflt=\vimgflt%
        ##1%
        \end{floatingfigure}%
        \setlength\vposflt\pagetotal%
        \global\vposflt=\vposflt%
        }%
    \clearflt
    \hspace{0pt}%
    \begin{floatingfigure}[l]{4cm}}%
    {}

\newcommand{\clearflt}{
    \par
    \setlength\vtypesetflt{\dimexpr\pagetotal-\vposflt}
    \ifdim \vtypesetflt<\vimgflt \setlength\vspaceflt{\dimexpr\vimgflt-\vtypesetflt+\baselineskip} \else \setlength\vspaceflt{0pt} \fi
    \vspace{\vspaceflt}
    }

\let\Oldsection\section
\renewcommand{\section}{\clearflt\Oldsection}
% end preamble.tex

\begin{document}
\begin{description}
\itemsep1pt\parskip0pt\parsep0pt
\item[\includegraphics{example-image-a}]
Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Etiam lobortis facilisis
sem. Nullam nec mi et neque pharetra sollicitudin.
\end{description}

\begin{description}
\itemsep1pt\parskip0pt\parsep0pt
\item[\includegraphics{example-image-b}]
Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Etiam lobortis facilisis
sem. Nullam nec mi et neque pharetra sollicitudin.
\end{description}

\section{Section title}
\begin{description}
\itemsep1pt\parskip0pt\parsep0pt
\item[\includegraphics{example-image-c}]
Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Etiam lobortis facilisis
sem. Nullam nec mi et neque pharetra sollicitudin.
\end{description}

\blindtext
\end{document}