Re: NSBezierPath geometry question...

FROM : David Phillip Oster
DATE : Mon Apr 11 18:46:18 2005

At 7:38 AM -0700 4/11/05, Robert Clair <<email_removed>> wrote:
>There is no cubic Bezier that is exactly a circular arc, the best you
>can do is an approximation. However this isn't what you want - it's a
>very bad approximation of an arc.


I've read this claim before but never understood it. Since a
NSBezierPath is a cubic polynomial, why in the world would it have
any trouble representing an arc, which is a quadratic polynomial?:
just set the coefficients of the x^3 term to zero, and it IS a
quadratic polynomial. (or in bezier speak: if the two off axis
control points are in the same place, you've got a quadratic spline,
which should be the same as a segment of arc.

David Phillip Oster