[texworks] Trigger refresh of pdf view?

[Duncan Murdoch]

I'm using TeXWorks with a preprocessor (Sweave).  I have a custom 
typesetting command set up to run the preprocessor, then run the result 
through pdflatex.  I'm having some problems.

The file that is processed might not have the same basename as the .pdf 
file.  (e.g. chapter.Rnw might lead to book.pdf being produced.)  The 
preprocessor is capable of running a system command after producing the 
.pdf file, so I have it running "texworks book.pdf", but this won't 
update an existing view of the same file.

Is there a way to tell TeXWorks to update the preview?  I was thinking 
maybe an "aftertypeset" hook could do it, but I can't find any examples 
of those.  Is there a collection somewhere of examples of scripts?

Thanks for any suggestions or pointers.

Duncan Murdoch