scratchfoundation/paper.js
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Shorten new edge case code in getWinding() a bit.

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Jürg Lehni 2014-02-24 20:29:44 +01:00
parent 9e8dbc7c3e
commit 14df7b5d5a
1 changed files with 15 additions and 17 deletions
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32
src/path/PathItem.Boolean.js
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@ -259,8 +259,7 @@ PathItem.inject(new function() {
windRight = 0,
roots = [],
abs = Math.abs,
ONE = 1 - TOLERANCE,
rootMaxLimit = ONE;
MAX = 1 - TOLERANCE;
// Absolutely horizontal curves may return wrong results, since
// the curves are monotonic in y direction and this is an
// indeterminate state.
@ -302,19 +301,18 @@ PathItem.inject(new function() {
values = curve.values,
winding = curve.winding,
next = curve.next;
// Since the curves are monotone in y direction, we can just
// compare the endpoints of the curve to determine if the
// ray from query point along +-x direction will intersect
// the monotone curve. Results in quite significant speedup.
var interceptTest = winding === 1
? (y >= values[1] && y <= values[7])
: (y >= values[7] && y <= values[1]);
// If the next curve is horizontal, we have to include the end
// points of this curve to make sure we won't miss an intercept
rootMaxLimit = (next.winding === 0 && next.values[1] === y)
? 1 : ONE;
if (winding !== 0 && interceptTest && Curve.solveCubic(
values, 1, y, roots, 0, rootMaxLimit) === 1) {
// Since the curves are monotone in y direction, we can just
// compare the endpoints of the curve to determine if the
// ray from query point along +-x direction will intersect
// the monotone curve. Results in quite significant speedup.
if (winding && (winding === 1
&& y >= values[1] && y <= values[7]
|| y >= values[7] && y <= values[1])
&& Curve.solveCubic(values, 1, y, roots, 0,
// If the next curve is horizontal, we have to include
// the end of this curve to make sure we won't miss an
// intercept.
!next.winding && next.values[1] === y ? 1 : MAX) === 1){
var t = roots[0],
x0 = Curve.evaluate(values, t, 0).x,
slope = Curve.evaluate(values, t, 1).y;
@ -330,9 +328,9 @@ PathItem.inject(new function() {
++windRight;
}
} else if (x0 <= xBefore) {
windLeft += curve.winding;
windLeft += winding;
} else if (x0 >= xAfter) {
windRight += curve.winding;
windRight += winding;
}
}
}