Diagonally placed, repeated watermark text above the entire content of a tcolorbox

Question

Consider this MWE:

\documentclass[table]{standalone}
\usepackage{graphicx, polyglossia, lipsum}
\usepackage[most]{tcolorbox}

\newtcolorbox{mybox}[2][]{%
  enhanced,
  before upper=\setlength{\parskip}{\bigskipamount},
  colframe=black,
  boxrule=2mm,
  bottomrule=8mm,
  colbacktitle=black,
  fonttitle=\bfseries\centering,
  overlay app={%
    \node[white, anchor=south, text width=.95\textwidth] at (frame.south) {Some footer text};},
  title=#2,#1}

\newcommand{\xxbody}{
  \lipsum[2]

  \noindent\includegraphics[width=\textwidth]{example-image-golden}

  \lipsum[3]
}

\newcommand{\xxheading}{%
  Heading
}

\begin{document}

\begin{mybox}{\LARGE \xxheading{}}

  \xxbody{}

\end{mybox}

\end{document}

I want to put some watermark text, say, 'Draft'. The text should run from the bottom left to top right corner of the text box and on lines parallel to that line. So, 'Draft' will appear multiple times. The angle of the text will change as the text box grows smaller or bigger.

It should be above the entire content, including the image.

Can this be done? How?

Answer 1

Like this?

\documentclass[table]{standalone}
\usepackage{graphicx, polyglossia, lipsum}
\usepackage[most]{tcolorbox}
\usetikzlibrary{patterns, calc}

\tcbset{ribbon/.style={finish={%
\begin{tcbclipframe}
\path (frame.south west) -- (frame.north east) let \p1=($(frame.north east)-(frame.south west)$) in node[red, midway, sloped, font=\Huge\bfseries, align=center, text width={veclen(\x1,\y1)}] {Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft};
    \end{tcbclipframe}}}}

\newtcolorbox{mybox}[2][]{%
  enhanced,
  before upper=\setlength{\parskip}{\bigskipamount},
  colframe=black,
  boxrule=2mm,
  bottomrule=8mm,
  colbacktitle=black,
  fonttitle=\bfseries\centering,
  overlay app={%
    \node[white, anchor=south, text width=.95\textwidth] at (frame.south) {Some footer text};}
    overlay={
    \path (frame.south west)--(frame.north east) node[red, draw, midway, sloped, font=\Large] {Draft\\ Draft\\ Draft};},
  title=#2,#1}

\newcommand{\xxbody}{
  \lipsum[2]

  \noindent\includegraphics[width=\textwidth]{example-image-golden}

  \lipsum[3]
}

\newcommand{\xxheading}{%
  Heading
}

\begin{document}

\begin{mybox}[ribbon]{\LARGE \xxheading{}}

  \xxbody{}

\end{mybox}

\end{document}

Update:

To just cover text part, tcbclipinterior can be used. To cover the whole contents, a longer text is needed or a longer text and larger scale.

If you want to be sure that everything is covered, instead of a unique node, several independent lines can be drawn.

\documentclass[table]{standalone}
\usepackage{graphicx, polyglossia, lipsum}
\usepackage[most]{tcolorbox}
\usetikzlibrary{patterns, calc}

\tcbset{ribbon/.style={finish={%
\begin{tcbclipinterior}
\path (frame.south west) -- (frame.north east) let \p1=($(frame.north east)-(frame.south west)$) in node[red, midway, sloped, font=\Huge\bfseries, align=center, text width={veclen(\x1,\y1)}, scale=2, opacity=.5] {Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft Draft};
    \end{tcbclipinterior}}}}

\newtcolorbox{mybox}[2][]{%
  enhanced,
  before upper=\setlength{\parskip}{\bigskipamount},
  colframe=black,
  boxrule=2mm,
  bottomrule=8mm,
  colbacktitle=black,
  fonttitle=\bfseries\centering,
  overlay app={%
    \node[white, anchor=south, text width=.95\textwidth] at (frame.south) {Some footer text};}
    overlay={
    \path (frame.south west)--(frame.north east) node[red, draw, midway, sloped, font=\Large] {Draft\\ Draft\\ Draft};},
  title=#2,#1}

\newcommand{\xxbody}{
  \lipsum[2]

  \noindent\includegraphics[width=\textwidth]{example-image-golden}

  \lipsum[3]
}

\newcommand{\xxheading}{%
  Heading
}

\begin{document}

\begin{mybox}[ribbon]{\LARGE \xxheading{}}

  \xxbody{}

\end{mybox}

\end{document}