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Re: no solution found for Bezier intersection


From: David Kastrup
Subject: Re: no solution found for Bezier intersection
Date: Mon, 02 Jul 2018 14:32:24 +0200
User-agent: Gnus/5.13 (Gnus v5.13) Emacs/27.0.50 (gnu/linux)

Thomas Morley <address@hidden> writes:

> Hi,
>
> the code below returns
> programming error: no solution found for Bezier intersection
> for 2.19.82 as well as for current master. 2.18.2 is ok.

Ok, as far as I can see that is just the consequence of massively
numerically naive coding.

Basically, there is a routine finding the y value for a corresponding x
value on a Bézier curve, and it's fed a value from the edge of the
curve.  It then proceeds to solve cubic equations and derives some point
just outside of the curve which it then discards.

And then it acts confused because it was sure about there being some
kind of intersection.

I'll take a thorough look at this code.  Looks like it could benefit
from a more graphic approach to intersections than converting everything
into zero-based polynomials and then doing root finding.

-- 
David Kastrup



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