[Tex/LaTex] TikZ: using the pos = x in a node

Question

Why doesn't the pos = x option work when the node is used in the plot command?

\documentclass[tikz]{standalone}
\begin{document}
\begin{tikzpicture}
  \draw plot[domain = 0:2, samples = 100] ({\x}, {(\x)^2}) node[pos = 1.1] 
  {\(y = x^2\)};
\end{tikzpicture}
\end{document}

In this picture, f_{quad} is my node that should be at pos = 1.1.

Additionally, it doesn't matter what I make pos equal to. It is always at the origin.

Answer 1

My feeling is that the plot operation is special and the way in which TikZ process it differs with respect to how canonical paths are processed. Quoting the manual:

The plot path operation can be used to append a line or curve to the path that goes through a large number of coordinates.

This suggests that the whole plot is appended to the path and thus that could be a possible reason why nodes can be appended only at the beginning or at the end of a plot path.

However, it is always possible to exploit the decorations.markings library as a workaround.

An example:

\documentclass[tikz,png,border=10pt]{standalone}
\usetikzlibrary{decorations.markings}

\tikzset{insert node/.style args={#1 at #2}{
    postaction=decorate,
    decoration={
      markings,
      mark= at position #2
        with
        {
         #1
        }
    }
  }
}
\begin{document}
\begin{tikzpicture}
  \draw[insert node={\node[red,left]{\(y = x^2\)};} at 0.65,
  insert node={\node[blue,draw,right]{\(y = x^2\)};} at 0.45,
  insert node={\node[green!80!black,above]{\(y = x^2\)};} at 1,
  ] plot[domain = 0:2, samples = 100] ({\x}, {(\x)^2});
\end{tikzpicture}
\end{document}

The result: