scratchfoundation/paper.js
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Find a better strategy to avoid duplicate solutions in PathItem#getIntersections().

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Closes .
This commit is contained in:
Jürg Lehni 2013-04-09 20:27:55 -07:00
parent 2c3e8a32ab
commit a9a0857ba4
3 changed files with 20 additions and 16 deletions
src/path
Curve.js

26
src/path/Curve.js
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@ -650,15 +650,7 @@ statics: {
strokeWidth: 0.1
});
/*#*/ }
// We are not using Rectangle#intersects() here, since in order to
// detect intersections that lie on curve bounds, we need to consider
// touching on one side of the tested rectangles as intersection as well
// If touch is condired at both sides, solutions lying on the border of
// bounds would turn up twice.
if (bounds1.x + bounds1.width >= bounds2.x
&& bounds1.y + bounds1.height >= bounds2.y
&& bounds1.x < bounds2.x + bounds2.width
&& bounds1.y < bounds2.y + bounds2.height) {
if (bounds1.touches(bounds2)) {
// See if both curves are flat enough to be treated as lines.
if (Curve.isFlatEnough(v1, /*#=*/ Numerical.TOLERANCE)
&& Curve.isFlatEnough(v2, /*#=*/ Numerical.TOLERANCE)) {
@ -673,12 +665,16 @@ statics: {
});
/*#*/ }
// See if the parametric equations of the lines interesct.
var point = new Line(v1[0], v1[1], v1[6], v1[7], false)
.intersect(new Line(v2[0], v2[1], v2[6], v2[7], false));
// Passing null for parameter leads to lazy determination of
// parameter values in CurveLocation#getParameter() only once
// they are requested.
if (point)
var line1 = new Line(v1[0], v1[1], v1[6], v1[7], false),
line2 = new Line(v2[0], v2[1], v2[6], v2[7], false),
point = line1.intersect(line2);
// Filter out beginnings of the curves, to avoid duplicate
// solutions where curves join.
if (point && !point.equals(line1.point)
&& !point.equals(line2.point))
// Passing null for parameter leads to lazy determination of
// parameter values in CurveLocation#getParameter() only
// once they are requested.
locations.push(new CurveLocation(curve, null, point));
} else {
// Subdivide both curves, and see if they intersect.