Problem with tikzpagenodes and minipage

Question

Using the anchors defined by tikzpagenodes inside a minipage produces unexpected results; this is not the case for the current page family of anchors defined by standard TikZ as the following example shows.

Labels in cyan correspond to the standard TikZ anchors which are correctly positioned ("cp" stands for "current page"); labels in orange correspond to tikzpagenodes anchors which are correctly positioned ("ta" stands for "text area"); labels in red correspond to tikzpagenodes anchors which are not correctly positioned since the anchors were called from withing a minipage ("ta" stands for "text area"). The showframe package was used to have a visual guide of the page layout; the minipage also was framed for reference

\documentclass{article}
\usepackage[a6paper]{geometry}
\usepackage{tikzpagenodes}
\usepackage{showframe}

\begin{document}

\centering

\begin{tikzpicture}[remember picture,overlay]
\foreach \Anchor in {north,west,south,east}
{
  \node[font=\color{orange}] at (current page text area.\Anchor) {ta.\Anchor};
  \node[font=\Huge\color{orange}] at (current page text area.\Anchor) {X};
}
\end{tikzpicture}%

\frame{\begin{minipage}[c][4cm][c]{.5\textwidth}
\begin{tikzpicture}[remember picture,overlay]
\foreach \Anchor in {north,west,south,east}
{
  \node[font=\color{cyan}] at (current page.\Anchor) {cp.\Anchor};
  \node[font=\Huge\color{cyan}] at (current page.\Anchor) {X};
  \node[font=\color{red}] at (current page text area.\Anchor) {ta.area.\Anchor};
  \node[font=\Huge\color{red}] at (current page text area.\Anchor) {X};
}
\end{tikzpicture}%
\end{minipage}}

\end{document}

How can the correct anchors defined by tikzpagenodes be recovered when used inside a minipage.

Answer 1

You may use the fit library to define a global "good" current page text area:

\tikz[remember picture,overlay]
\node[fit=(current page text area),line width=0,inner sep=0,name=good current page text area]{};

Example:

\documentclass{article}
\usepackage[a6paper]{geometry}
\usepackage{tikzpagenodes}
\usetikzlibrary{fit}
\usepackage{showframe}

\begin{document}

\centering
\tikz[remember picture,overlay]
\node[fit=(current page text area),line width=0,inner sep=0,name=good current page text area]{};
\begin{tikzpicture}[remember picture,overlay]
\foreach \Anchor in {north,west,south,east}
{
  \node[font=\color{orange}] at (current page text area.\Anchor) {ta.\Anchor};
  \node[font=\Huge\color{orange}] at (current page text area.\Anchor) {X};
}
\end{tikzpicture}%

\frame{\begin{minipage}[c][4cm][c]{.5\textwidth}
\begin{tikzpicture}[remember picture,overlay]
\foreach \Anchor in {north,west,south,east}
{
  \node[font=\color{cyan}] at (current page.\Anchor) {cp.\Anchor};
  \node[font=\Huge\color{cyan}] at (current page.\Anchor) {X};
  %\node[font=\color{red}] at (current page text area.\Anchor) {ta.area.\Anchor};
  %\node[font=\Huge\color{red}] at (current page text area.\Anchor) {X};
  \node[font=\color{blue}] at (good current page text area.\Anchor) {ta.area.\Anchor};
  \node[font=\Huge\color{blue}] at (good current page text area.\Anchor) {X};

}
\end{tikzpicture}%
\end{minipage}}

\end{document}