I'm interested in drawing a logo with Tikz to embed either as a PDF or as a code snippet in other Tex documents. In order to do this, I'd like to draw the logo in a small PDF file, size 1 inch by 1 inch. I try the following code and curiously, it seems that geometry has additional parameters influencing the shape of the PDF. What must I "set to zero" so that drawing a 1inch diameter circle intersects all edges of the PDF as viewed?

```
\documentclass{slides}
\usepackage[paperwidth=1in, paperheight=1in, margin=0in]{geometry}
\usepackage{tikz}

\begin{document}
\begin{tikzpicture}
    \draw (0.5, 0.5) circle (1);
\end{tikzpicture}
\end{document}

```