Mein LaTeX-Forum

\documentclass[titlepage=true]{scrartcl}
\usepackage{tikz}
\usetikzlibrary{calc,positioning}% [0]
\usepackage{mwe}
\usepackage{graphicx}
\begin{document}
\begin{tikzpicture}[overlay,remember picture]
 \coordinate (left upper corner) at  ([xshift=25mm,yshift=10cm] current page.south west);
 \coordinate (right bottom corner) at  ([xshift=-7mm,yshift=8cm] current page.south east);
 \fill[red] (left upper corner) rectangle (right bottom corner);
 \draw[blue,<->] (left upper corner)--++ (-25mm,0)node[midway,above]{25mm};
 \draw[blue,<->] (right bottom corner)--++ (7mm,0)node[midway,above]{7mm};    
 \draw[blue,<->] (right bottom corner)--++ (0,-8cm)node[midway,above]{8cm};
\end{tikzpicture}
blub
\end{document}