Creating vector logos for embedding in other tex documents

Question

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}

Answer 1

Rather use

\documentclass{standalone}

Then you don't even need the geometry package. It automatically sets the size of the 'canvas' to the size of the bounding box.

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Edit by percusse: Still, for the fun of it, you can get rid of the \hoffset and also you should make sure that the line width is also taken into account. Lastly, you need to use in instead of the default cm for the units.

\documentclass{article}
\usepackage[paperwidth=1in, paperheight=1in, margin=0in]{geometry}
\usepackage{tikz}
\setlength\hoffset{0in}
\begin{document}
\noindent\tikz\draw (0.5in+0.5pt,0.5in) circle (0.5in-0.25pt);
\end{document}

Answer 2

You can also get a tight vector image by using preview package as follow.

\documentclass{article}
\usepackage{pstricks}

\usepackage[active,tightpage]{preview}
\PreviewBorder=12pt% you can set it to 0pt if you don't need a border.
\PreviewEnvironment{pspicture}


\begin{document}
\psset{unit=1in}% one unit equals to 1 inch.
\begin{pspicture}[showgrid](1,1)
    \pscircle[fillstyle=solid,fillcolor=yellow,opacity=0.5](0.5,0.5){0.5}
\end{pspicture}
\end{document}