scratchfoundation/paper.js
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Restructure code that determines median winding contribution.

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Jürg Lehni 2015-01-03 00:26:13 +01:00
parent 5f0e545ba7
commit bb2fece225
1 changed files with 27 additions and 29 deletions
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56
src/path/PathItem.Boolean.js
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@ -63,7 +63,6 @@ PathItem.inject(new function() {
var chain = [],
windings = [],
lengths = [],
segments = [],
// Aggregate of all curves in both operands, monotonic in y
monoCurves = [];
@ -96,12 +95,13 @@ PathItem.inject(new function() {
// contribution for this curve-chain. Once we have enough confidence
// in the winding contribution, we can propagate it until the
// intersection or end of a curve chain.
chain.length = windings.length = lengths.length = 0;
var totalLength = 0,
startSeg = segment;
chain.length = 0;
var startSeg = segment,
totalLength = 0;
do {
chain.push(segment);
lengths.push(totalLength += segment.getCurve().getLength());
var length = segment.getCurve().getLength();
chain.push({ segment: segment, length: length });
totalLength += length;
segment = segment.getNext();
} while (segment && !segment._intersection && segment !== startSeg);
// Select the median winding of three random points along this curve
@ -109,36 +109,34 @@ PathItem.inject(new function() {
// gives a better chance of returning a correct winding than equally
// dividing the curve chain, with the same (amortised) time.
for (var j = 0; j < 3; j++) {
var length = totalLength * Math.random(),
amount = lengths.length,
k = 0;
do {
if (lengths[k] >= length) {
if (k > 0)
length -= lengths[k - 1];
var length = totalLength * Math.random();
for (k = 0, m = chain.length; k < m; k++) {
var entry = chain[k];
if (length <= entry.length) {
var curve = entry.segment.getCurve(),
pt = curve.getPointAt(length),
hor = curve.isHorizontal(),
path = curve._path;
if (path._parent instanceof CompoundPath)
path = path._parent;
// While subtracting, we need to omit this curve if this
// curve is contributing to the second operand and is
// outside the first operand.
windings[j] = subtract && _path2
&& (path === _path1 && _path2._getWinding(pt, hor)
|| path === _path2 && !_path1._getWinding(pt, hor))
? 0
: getWinding(pt, monoCurves, hor);
break;
}
} while (++k < amount);
var curve = chain[k].getCurve(),
point = curve.getPointAt(length),
hor = curve.isHorizontal(),
path = curve._path;
if (path._parent instanceof CompoundPath)
path = path._parent;
// While subtracting, we need to omit this curve if this
// curve is contributing to the second operand and is outside
// the first operand.
windings[j] = subtract && _path2
&& (path === _path1 && _path2._getWinding(point, hor)
|| path === _path2 && !_path1._getWinding(point, hor))
? 0
: getWinding(point, monoCurves, hor);
length -= entry.length;
}
}
windings.sort();
// Assign the median winding to the entire curve chain.
var winding = windings[1];
for (var j = chain.length - 1; j >= 0; j--)
chain[j]._winding = winding;
chain[j].segment._winding = winding;
}
// Trace closed contours and insert them into the result.
var result = new CompoundPath();