[OS X TeX] bizarre preview difference for TeXshop and Adobe Acrobat

[William Adams]

I'm trying to get a rule snugged up against the top of the page.

Typesetting the following and viewing it at an 875% magnification in  
TeXshop 2.26 running on Mac OS X 10.5.8 looks correct:

\documentclass{minimal}
\usepackage[margin=0bp,paperwidth=174pt,paperheight=36pt]{geometry}
\begin{document}%
\newlength{\textlineheight}%
\newsavebox{\scratch}%
\setbox\scratch=\vtop{\strut}%
\textlineheight=\ht\scratch%
\noindent\begin{picture}(0,0)\put(0,0)%
{\rule[\textlineheight]{174pt}{1pt}}%
\end{picture}%
Test\begin{picture}(0,0)\put(0,0)%
{\rule{1in}{1bp}}%
\end{picture}%
Test\end{document}

But then when viewing it in Adobe Acrobat there's an obvious gap and  
when measuring it in Adobe Illustrator or using PitStop the centerline  
of the rule is 1.096 PostScript Points from the top of the page.

It looks right in Preview.app as well.

Anyone have any suggestions?

William

-- 
William Adams
senior graphic designer
Fry Communications
Sphinx of black quartz, judge my vow.