# A TikZ image set to the width of the entire paper, without changing the header and footer positions and widths

I'm attempting to fit a TikZ image on a page, and would like to make the image as large as possible, without distorting its dimensions. However, at the same time I would also like to be able to display my name in the header on that same page, without the header being moved in any way by my other manipulations. This is where things get complicated, as I was able to move the image to start from the left edge of the page by practically removing the left margin, but this also moves the headers and footers on that page, as shown in the following image.

The source code for the page is here:

\documentclass[12pt,a4paper]{article}

\usepackage[showframe]{geometry}

\usepackage{fancyhdr}
\pagestyle{fancy}
\makeatletter
\let\runchapter\@chapter
\let\runsection\@thesection
\makeatother

\usepackage{pgfplots}
\usetikzlibrary{matrix}
\colorlet{harmful}{red!30}
\colorlet{internal}{yellow!20}
\colorlet{external}{cyan!30}
\colorlet{W}{harmful!50!internal}
\colorlet{T}{harmful!50!external}

\begin{document}

\vfill

\newgeometry{left=0cm,right=0cm}

\thispagestyle{fancy}

\begin{figure}[p]

\centering
\begin{tikzpicture}[
any/.style={minimum width=0.475\paperwidth,minimum height=0.475\paperwidth,%
text width=7cm,align=center,outer sep=0pt},
mycolor/.style={fill=#1, text=#1!60!black}
]

\matrix (SWOT) [matrix of nodes,nodes={any,anchor=center},%
column sep=-\pgflinewidth,%
row sep=-\pgflinewidth,%
column 1/.style={nodes=leftcol},
inner sep=0pt,
outer sep=5em]
{
|[fill=internal]| {Internal Origin} & |[mycolor=S]| { \fontsize{60}{70}\selectfont S} & |[mycolor=W]| { \fontsize{60}{70}\selectfont W} \\
|[fill=external]| {External Origin} & |[mycolor=O]| { \fontsize{60}{70}\selectfont O} & |[mycolor=T]| { \fontsize{60}{70}\selectfont T} \\
};

\node[any, anchor=center] at (SWOT-2-2) {};
\node[any, anchor=center] at (SWOT-2-3) {};
\node[any, anchor=center] at (SWOT-3-2) {};
\node[any, anchor=center] at (SWOT-3-3) {};

\end{tikzpicture}
\end{figure}
\vfill

\restoregeometry

\end{document}


The page looks rather ugly, as the header and footer start right at the left side of the page. I would rather the header and footer widths and positions be unchanged by my moving of the left and right margins. How can this be achieved, since the geometry package doesn't seem to differentiate between header/footer and body margins?

  \fancyhfoffset[L]{-0.1\paperwidth}
\fancyhfoffset[R]{-0.1\paperwidth}


after \usepackage{fancydr} fixed the issue.