In my original version, the picture was sacaled nicely to the full width of the page. Unfortunatelly, I don't have a screenshot of that. Then I increased radius to 5 (everything fine), decreased it again, an now the picture is too small:
Any hint?
\documentclass[12pt]{article}
\usepackage{fancyhdr}
\usepackage{tikz}
\usepackage[ngerman]{babel}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{graphicx}
\usepackage{epstopdf}
\usepackage{mathtools}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{url}
\usepackage[parfill]{parskip}
\usepackage{enumerate}
\usepackage{framed}
\usepackage{xcolor}
\pagestyle{fancy}
\lhead{\textsf{x}}
\rhead{\textsf{x}}
\lfoot{\textsf{\tiny x \LaTeX \ | \today}}
\setlength{\headheight}{15pt}
\begin{document}
$\blacksquare$ \textbf{x}
\begin{tikzpicture}[>=latex][transform canvas={scale=2.0}]
% Draw the lines at multiples of pi/6
\foreach \ang in {0,...,11} {
\draw [lightgray] (0,0) -- (\ang*360/12:2.5);
}
% Draw the lines at multiples of pi/4
\foreach \ang in {0,...,7} {
\draw [lightgray] (0,0) -- (\ang*360/8:2.5);
}
% Concentric circles and radius labels
\foreach \s in {0, 1, 2} {
\draw [lightgray] (0,0) circle (\s + 0.5);
\draw (0,0) circle (\s);
\node [fill=white] at (\s, 0) [below] {\scriptsize $\s$};
}
% Add the labels at multiples of pi/4
\foreach \ang/\lab/\dir in {
0 /0 /right,
1 /{\pi/4} /{above right},
2 /{\pi/2} /above,
3 /{3\pi/4}/{above left},
4 /{\pi} /left,
5 /{5\pi/4}/{below left},
7 /{7\pi/4}/{below right},
6 /{3\pi/2}/below} {
\node [fill=white] at (\ang*360/8:2.6) [\dir] {\scriptsize $\lab$};
}
% The double-lined circle around the whole diagram
\draw [style=double] (0,0) circle (2.5);
\end{tikzpicture}
\end{document}
Example from here. Related questions 1 and 2 didn't solve the problem or I missed something.

