[metapost] Pen stroking and tight curves

[Shriramana Sharma]

On Mon, Oct 22, 2012 at 7:01 AM, xiolyxioly <xiolyxioly at yahoo.com> wrote:

>  People in CAD/CAM do this sort of computation all the time. It's called
> "removing loops from offset curves" or something like that. The problem of
> moving an NC milling cutter around a tight corner is exactly the same as
> moving a pen. I'll find some references, if anyone is interested.
>

CiteSeerX — Hermite Approximation for Offset Curve
Computation<http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.43.1724>is
one ref which actually discusses this problem (though not w.r.t. fonts
specifically). However the author writes here that the curvature is the
inverse of the diameter. I however think that it should be the inverse of
the radius, going by http://en.wikipedia.org/wiki/Curvature (and other refs
I've seen so far).

BTW I downloaded the other two links you sent and will read them in due
course. I'd also appreciate any other docs you can provide.

Another thing: I'm not sure that it is a straightforward thing to compute
the points of reverse loops if your pen is anything other than circular.

-- 
Shriramana Sharma
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