RE: rounding error in cubic Beziers?

Oh by the way, both examples are all SMIL (no JavaScript) so the animation
is not working in IE (alas), though the gaps between the curves are still
visible in IE.

 

D

 

From: [email protected] [mailto:[email protected]]
On Behalf Of David Dailey
Sent: Thursday, February 27, 2014 8:49 AM
To: [email protected]
Subject: [svg-developers] rounding error in cubic Beziers?

 

  

Hi folks,

 

In the file at http://cs.sru.edu/~ddailey/SwirlRoundPat.svg , I think there
should have no gaps between the tiles in the four-tile tessellation. Do make
the gaps visible and truly annoying, I've animated a pattern underneath.
You'll note that, as probably expected, the gaps are most pronounced at
points of maximum change in slope of the curve.

 

Before I raise this question of whether or not these gaps should be
"acceptable" (I rather think they shouldn't be, since they are wider than a
pixel and reflect rounding error, I think, in the calculation of the
coordinates of the Bezier curves) I wanted to see if there are magical
controls that could be applied to minimize the problem.

 

I tried shape-rendering="geometricPrecision" on the single path (re-used
rotated, grouped and reused again) thinking that that might tell browsers
that I really don't want the gaps in my tiling, but I haven't used that
before and am not sure I did it right, or if, in fact, it actually does
anything.

 

See also http://cs.sru.edu/~ddailey/fading/slides/animSwirl2c.svg for a fun
use of this  particular tessellation.

 

Cheers

David

 

 





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