[OS X TeX] QR codes

[Juan Luis Varona]

Dear friends,

This is a strange behavior in the mac:

Lel's execute this code copied from
http://tex.stackexchange.com/questions/1429/latex-package-to-generate-qr-codes

-----

\documentclass{standalone}
\usepackage{pst-barcode}
%\usepackage{auto-pst-pdf} % uncomment this if used with pdflatex
\begin{document}
  \begin{pspicture}(1.0in,1.0in)
    \psbarcode{Some text}{}{qrcode}
  \end{pspicture}
\end{document}

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If you see the pdf with Apple Preview, or with TeXShop, or Skim, 
and yo do a lot of zoom, it seems that the pdf is not vectorial, 
because you see points of different gray level.

This does not happens with Adobe Reader. Why?

Yours,

Juan Luis Varona