[R] Using an image background with graphics

[Waichler, Scott R]

Dr. Ripley,

Thank you, yes, it's the anti-aliasing thing again.  I'm using Redhat
EL4, R-2.8.0, and pdf().  I had the problem with images displayed in
xpdf, even with xpdf -aa no.  I do not get the problem in Adobe Reader
7.0 for Linux.  I'll try harder to remember this point.
 
Scott Waichler
Pacific Northwest National Laboratory
scott.waichler at pnl.gov

> Most likely this is a bug in your pdf viewer: try turning off 
> anti-aliasing there (or use a better viewer, if that is not 
> an option).
> It is a symptom of anti-aliasing of the rectangles used to 
> plot image pixels.