The horizontal bar from the following MWE does not start at the left edge of the paper as expected, but rather a bit more to the right. The line is 17cm long and the page width is also 17cm, which results in the warning
Overfull \hbox (1.59978pt too wide) in paragraph at lines 9--10
I tried adding '%' signs at the end of all the lines without any effect. What am I missing please?
\documentclass{article}
\usepackage[a4paper, showframe, margin=2cm]{geometry}
\usepackage{tikz}
\setlength{\parindent}{0pt}
\begin{document}
\begin{tikzpicture}
\draw[ultra thick] (0,0) -- (17,0);
\end{tikzpicture}
\end{document}


current bounding box. This answer still produces the same output. However, the TikZ picture reports a box of zero size back to TeX. (It basically\smashes and\rlapthe diagram.) TryFoo\tikz[overlay]\draw[ultra thick] (0,0) -- (17cm,0);Barto see that more clearly. For a simple horizontal line on its own paragraph, this is okay. – Qrrbrbirlbel Nov 16 '23 at 21:45