TikZ-PGF Annotations – Annotate Math Equation with Text on Arrows

Question

is there any particular way to get something similar to that in tikz with or without any packages?

Answer 1

This is a continuation of Fractal's nice answer the purpose of which is to make the formulae fit in the document without overlapping.

\documentclass{article}
\usepackage[charter]{mathdesign}
\usepackage{tikz}
\usetikzlibrary{tikzmark}
\usetikzlibrary{calc}
\begin{document}
Blah blah blah blah blah blah blah blah blah\dots
\[\int\limits
  _{\tikzmarknode{a}{a}}
  ^{\tikzmarknode{b}{b}}\tikzmarknode{f}{f}(\tikzmarknode{x1}{x})
  \,\tikzmarknode{d}{\mathrm{d}}\tikzmarknode{x2}{x}
\begin{tikzpicture}[overlay,remember picture,cyan,>=stealth,shorten
 <=0.2ex,nodes={font=\tiny,align=left,inner ysep=1pt},<-]
  \draw ([xshift=-0.3ex]b.west|-x2) -- ++ (-1.5em,0) node[left] (l) {\textbf{Integral}};
  \draw (a.south) -- ++ (0,-1.5em) node[anchor=north west,align=left,xshift=-1.2ex]
    (u) {\textbf{Untergrenze}\\ Untere integrationsgrenze};
  \draw (b.north) -- ++ (0,1.5em) node[anchor=south west,align=left,xshift=-1.2ex]
    (o) {\textbf{Obergrenze}\\ Obere integrationsgrenze};
  \path (x1.north) ++ (0,1.5em) node[anchor=south west,xshift=-1.2ex] (il)
    {\textbf{Integrand}\\ Funktion \"uber die integriert werden soll};
  \draw (x1.north) |- ([xshift=0.3ex]il.south east);
  \path (d.south) ++ (0,-1.5em) node[anchor=north west] (diff)
    {\textbf{Differtential}};
  \draw (d.south) |- ([xshift=0.3ex]diff.south east);
  \draw ([xshift=0.3ex]x2.east) -- ++ (1.5em,0) node[right]  (r)
   {\textbf{Integrationsvariable}\\ Der Integrand wird \"uber $x$ integriert};
  \path let \p1=($(o.north)-(u.south)$),\p2=($(r.east)-(x2.east)$),
   \p3=($(a.west)-(l.west)$),\n1={\x2-\x3} in 
  \pgfextra{\xdef\tmpvspace{\y1}\xdef\tmphspace{\n1}};
\end{tikzpicture}\vcenter{\vspace{\tmpvspace}}
\hspace{\tmphspace} 
\]
Blah blah blah blah blah blah blah blah blah\dots
\[E=m\,c^2\]
\end{document}

If you comment out \hspace{\tmphspace} you get