[pstricks] \ncbezier?

[Bob Tennent]

 >|>  |>> I'd prefer to specify control points explicitly rather than compute
 >|>  |>> angle and curv parameters using atans and Pythagoras.
 
 >|> So then how would one would compute the arctangent of \theyy over \thexx
 >|> and save the result as \theangle, presumably using Postscript? 
 >|
 >|what for do you need the arc tan?
 >|arcangle={(\thexx,\theyy)}   does it internally.

arcangle is interpreted by \ncarc as as an angle to be added/subtracted
to/from the A to B direction:

\newcounter{xx}
\newcounter{yy}

\pnode(0,0){A}\pnode(4,4){B}

\setcounter{xx}{1}
\setcounter{yy}{3}
\rput(\thexx,\theyy){$\bullet$}
\SpecialCoor
\ncarc{A}{B}
\ncarc[arcangle={(\thexx,\theyy)}]{A}{B}

Bob T.