Right, but it seemed to me that if omxy was the "from" vector and mxy
was the "to" vector, that the computed mmxy should always be predictably
on the same side of it, no? If it was on the wrong side then it
wouldn't be a random occurence, it must be related to the input data.
So either it is always on the right side, always on the wrong side (i.e.
just reverse the rotation in the math), or always on the right/wrong
side depending on the CWness of the join angle - which would be
reflected in rev... No?
...jim
On 10/20/10 10:29 AM, Denis Lila wrote:
Cool, but above I was also asking the same question about line 231,
and you provided a lot of information about line 231 (and a test to verify
it), but didn't answer if the test in line 231 also tracks rev the
same way...?
Oh, no, line 231 isn't mean to be related to rev at all. It just checks
to see on which side of the (omx,omy),(mx,my) chord the computed (mmx, mmy)
is.
Regards,
Denis.
----- "Jim Graham"<james.gra...@oracle.com> wrote:
Hi Denis,
One clarification:
On 10/20/10 7:11 AM, Denis Lila wrote:
When would the isCW test trigger? Does it track "rev"? What
happens
at 180 degrees (is that test reliable for the randomization that
might
happen when omxy are directly opposite mxy)?
isCw is used for computing the arc bisector by testing whether the
computed
point is on the side it should be (and multiplying by -1 if not), it
is used
to compute the sign of cv in drawBezApproxForArc, and for computing
rev.
The only reason I ask is
because I think the sign of mmxy is probably controllable by
understanding the input conditions, but this test should be safe
(modulo if it really works at 180 degrees). If it has failure
modes at 180
degrees then reworking the math to produce the right sign in the
first
place may be more robust for that case. A test for this is to
render
"(0,0) -> (100,0) -> (0,0)" with round caps and then rotate it
through
360 degrees and see if the round caps invert at various angles.
I already did that. I drew 100 lines like the one you describe. I
attached
the results. It never fails. It is still possible that there could
be some
case where it fails, but this does prove that such a case would be
very rare.
Also, line 256 - does that track "rev"?
It does. I changed the test to if(rev).
...jim
