scratchfoundation/paper.js
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Remove need for sorted list of intersection curves, use variables instead.

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This commit is contained in:
Jürg Lehni 2014-02-20 15:17:39 +01:00
parent b960cbc07b
commit 5e7b15c64e
1 changed files with 19 additions and 25 deletions
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44
src/path/PathItem.js
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@ -435,10 +435,7 @@ statics: {
operator = operator || function() {
return true;
};
// A list of both curves at an intersection, except the entry curves
// along with their winding values and tangents.
var curves = [{}, {}],
paths = [],
var paths = [],
// Values for getTangentAt() that are almost 0 and 1.
// TODO: Correctly support getTangentAt(0) / (1)?
ZERO = 1e-3,
@ -467,29 +464,26 @@ statics: {
if (dir > 0)
c1 = c1.getPrevious();
var t1 = c1.getTangentAt(dir < 1 ? ZERO : ONE, true),
c4 = curves[1].c = interSeg.getCurve(),
c3 = curves[0].c = c4.getPrevious();
curves[0].t = c3.getTangentAt(ONE, true);
curves[1].t = c4.getTangentAt(ZERO, true);
// cross product of the entry and exit tangent vectors at
// the intersection, will let us select the correct countour
// to traverse next.
for (var j = 0; j < 2; j++)
curves[j].w = t1.cross(curves[j].t);
// Get both curves at the intersection (except the entry
// curves) along with their winding values and tangents.
c4 = interSeg.getCurve(),
c3 = c4.getPrevious(),
t3 = c3.getTangentAt(ONE, true),
t4 = c4.getTangentAt(ZERO, true),
// Cross product of the entry and exit tangent vectors
// at the intersection, will let us select the correct
// countour to traverse next.
w3 = t1.cross(t3),
w4 = t1.cross(t4);
// Do not attempt to switch contours if we aren't absolutely
// sure that there is a possible candidate.
if (curves[0].w * curves[1].w !== 0) {
curves.sort(function(a, b) {
// Compare tangents to sort curves counter clockwise
return a.w - b.w;
});
var j = 0,
nextSeg;
do {
var curve = curves[j++].c;
nextSeg = curve._segment1;
dir = curve === c3 ? -1 : 1;
} while (j < 2 && !operator(nextSeg._winding));
if (w3 * w4 !== 0) {
var curve = w3 < w4 ? c3 : c4,
nextCurve = operator(curve._segment1._winding)
? curve
: w3 < w4 ? c4 : c3,
nextSeg = nextCurve._segment1;
dir = nextCurve === c3 ? -1 : 1;
// If we didn't manage to find a suitable direction for
// next contour to traverse, stay on the same contour.
if (nextSeg._visited && seg._path !== nextSeg._path