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More simplifications in PathItem._getWinding()

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This commit is contained in:
Jürg Lehni 2014-02-20 13:46:10 +01:00
parent a2941472b5
commit de6650a6ca
1 changed files with 23 additions and 24 deletions
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47
src/path/PathItem.js
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@ -388,31 +388,30 @@ statics: {
windLeft = _getWinding(new Point(x, yTop), curves);
if (yBottom < Infinity)
windRight = _getWinding(new Point(x, yBottom), curves);
return Math.max(windLeft, windRight);
}
// Find the winding number for right hand side of the curve,
// inclusive of the curve itself, while tracing along its ±x direction.
for (var i = 0, l = curves.length; i < l; i++) {
var v = curves[i];
if (Curve.solveCubic(v, 1, y, roots, 0, 1 - tolerance) === 1) {
var t = roots[0],
x0 = Curve.evaluate(v, t, 0).x,
slope = Curve.evaluate(v, t, 1).y,
stationary = abs(slope) < tolerance && !Curve.isLinear(v)
// Take care of cases where the curve and the
// preceeding curve merely touches the ray towards
// +-x direction, but proceeds to the same side of
// the ray. This essentially is not a crossing.
// NOTE: The previous curve is stored at v[9],
// see Path#_getMonoCurves() for details.
} else {
// Find the winding number for right side of the curve, inclusive of
// the curve itself, while tracing along its +-x direction.
for (var i = 0, l = curves.length; i < l; i++) {
var v = curves[i];
if (Curve.solveCubic(v, 1, y, roots, 0, 1 - tolerance) === 1) {
var t = roots[0],
x0 = Curve.evaluate(v, t, 0).x,
slope = Curve.evaluate(v, t, 1).y;
// Take care of cases where the curve and the preceeding
// curve merely touches the ray towards +-x direction, but
// proceeds to the same side of the ray. This essentially is
// not a crossing.
// NOTE: The previous curve is stored at v[9], see
// Path#_getMonoCurves() for details.
if (abs(slope) < tolerance && !Curve.isLinear(v)
|| t < tolerance
&& slope * Curve.evaluate(v[9], t, 1).y < 0;
if (!stationary) {
var winding = v[8];
if (x0 <= xBefore)
windLeft += winding;
if (x0 >= xAfter)
windRight += winding;
&& slope * Curve.evaluate(v[9], t, 1).y < 0) {
// TODO: Handle stationary points here!
} else if (x0 <= xBefore) {
windLeft += v[8];
} else if (x0 >= xAfter) {
windRight += v[8];
}
}
}
}