[Tex/LaTex] Moving minipage on page to flush right with text

Question

I would like to place a box on every page of my LaTeX document that does not interfere with the typesetting of the rest of the document, and found that the watermark packages are suitable for the task; e.g., xwatermark.

Specifically, I would like to insert a framed minipage such that its right border coincides with the right border of the text body.

Considering the LaTeX page layout, I tried

\documentclass{article}

\usepackage{lipsum}

\newlength\xshift
\setlength\xshift{0.5\paperwidth}
\addtolength\xshift{-\marginparwidth}
\addtolength\xshift{-\marginparsep}
\addtolength\xshift{-1.0in} % half the minipage width
\addtolength\xshift{-1pt} % frame width

\usepackage{xcolor}
\usepackage[printwatermark]{xwatermark}
\newwatermark[
pages=1,
color=black,
scale=1,
xpos=\xshift,
ypos=0.0in
]{%
  \fbox{%
  \begin{minipage}{2.0in}\normalsize%
    my awesome minipage\\
    my awesome minipage\\
    my awesome minipage
  \end{minipage}%
}%
}

\begin{document}

\lipsum[1-4]

\end{document}

which results in

What might be the cause of the problem? Is there another package that is better suited?

Answer 1

You have to set \xshift like this

\setlength\xshift{\dimexpr0.5\paperwidth-\marginparwidth-\marginparsep-\oddsidemargin-1in\relax}

Full code:

\documentclass{article}

\usepackage{lipsum,showframe}

\newlength\xshift
\setlength\xshift{\dimexpr0.5\paperwidth-\marginparwidth-\marginparsep-\oddsidemargin-1in\relax}
%\addtolength\xshift{-\marginparwidth}
%\addtolength\xshift{-\marginparsep}
%\addtolength\xshift{-1.0in} % half the minipage width
%\addtolength\xshift{-1pt} % frame width

\usepackage{xcolor}
\usepackage[printwatermark]{xwatermark}
\newwatermark[
pages=1,
color=black,
scale=1,
xpos=\xshift,
ypos=0.0in
]{%
  \fbox{%
  \begin{minipage}{2.0in}\normalsize%
    my awesome minipage\\
    my awesome minipage\\
    my awesome minipage
  \end{minipage}%
}%
}

\begin{document}

\lipsum[1-4]

\end{document}