scratchfoundation/paper.js
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Winding: Improve handling of on-curve tangent checks.

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This commit is contained in:
Jürg Lehni 2016-07-23 13:30:40 +02:00
parent 27af304414
commit 31732917c0
1 changed files with 10 additions and 7 deletions
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17
src/path/PathItem.Boolean.js
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@ -379,9 +379,9 @@ PathItem.inject(new function() {
windingR = 0,
pathWindingL = 0,
pathWindingR = 0,
onPath = false,
onPathWinding = 0,
onPathCount = 0,
onPath = false,
roots = [],
vPrev,
vClose;
@ -425,7 +425,8 @@ PathItem.inject(new function() {
: Curve.getPoint(v, t)[dir ? 'y' : 'x'],
winding = o0 > o3 ? 1 : -1,
windingPrev = vPrev[io] > vPrev[io + 6] ? 1 : -1,
a3Prev = vPrev[ia + 6];
a3Prev = vPrev[ia + 6],
onCurve = false;
if (po !== o0) {
// Standard case, curve is not crossed at its starting point.
if (a < paL) {
@ -433,7 +434,7 @@ PathItem.inject(new function() {
} else if (a > paR) {
pathWindingR += winding;
} else {
onPath = true;
onCurve = true;
pathWindingL += winding;
pathWindingR += winding;
}
@ -449,7 +450,7 @@ PathItem.inject(new function() {
} else if (a3Prev < paL && a > paL || a3Prev > paR && a < paR) {
// Point is on a horizontal curve between the previous non-
// horizontal and the current curve.
onPath = true;
onCurve = true;
if (a3Prev < paL) {
// left winding was added before, now add right winding.
pathWindingR += winding;
@ -459,11 +460,13 @@ PathItem.inject(new function() {
}
}
vPrev = v;
// If we're on the path, look at the tangent to decide whether to
if (onCurve)
onPath = true;
// If we're on the curve, look at the tangent to decide whether to
// flip direction to determine a reliable winding number:
// If the tangent is parallel to the direction, call getWinding()
// again with flipped direction and return the result.
return onPath && !dontFlip
return onCurve && !dontFlip
&& Curve.getTangent(v, t)[dir ? 'x' : 'y'] === 0
&& getWinding(point, curves, dir ? 0 : 1, true);
}
@ -548,7 +551,7 @@ PathItem.inject(new function() {
// it now to treat the path as closed:
if (vClose && (res = handleCurve(vClose)))
return res;
if (!pathWindingL && !pathWindingR && onPath) {
if (onPath && !pathWindingL && !pathWindingR) {
// If the point is on the path and the windings canceled
// each other, we treat the point as if it was inside the
// path. A point inside a path has a winding of [+1,-1]