Re: Slur with left and/or right arrow head

[David Kastrup]

Thomas Morley <address@hidden> writes:

> Hi Aaron,
>
> thanks a lot for this.
> I was aware of not going for the bezier-curve itself, but only for the
> control-points was a raw approximation.
> Yours is far better.
> Mostly I did so for reasons of lacking knowledge of beziers, both the
> math and how to compute them.
> Now there is a fine tool-set available, many thanks again.
> I tried to understand what you coded (not finished yet), but while
> playing around with code I always think making it visible will help.
> Thus the attached file and image.
> One question I really couldn't answer is:
> What kind of value is `t´ in (define (bezier-angle control-points t) ...)
> Seems not to be a x- or y-value, not an arc-length-value .., but what
> else?

"time".  For t=0, you get the starting point, for t=1 you get the end
point.  For values in between, you get points in between.  The starting
direction is from starting point (control point 0) to control point 1
(which is not usually touched at all).  Similarly the ending direction
is from control point 2 to the end point (control point 3).

-- 
David Kastrup