scratchfoundation/paper.js
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Clean up PathFitter fix a bit.

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Jürg Lehni 2015-04-04 15:54:34 +02:00
parent 66fbb9ee2a
commit 563a26f112
1 changed files with 22 additions and 22 deletions
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44
src/path/PathFitter.js
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@ -171,31 +171,33 @@ var PathFitter = Base.extend({
// If alpha negative, use the Wu/Barsky heuristic (see text) // If alpha negative, use the Wu/Barsky heuristic (see text)
// (if alpha is 0, you get coincident control points that lead to // (if alpha is 0, you get coincident control points that lead to
// divide by zero in any subsequent NewtonRaphsonRootFind() call. // divide by zero in any subsequent NewtonRaphsonRootFind() call.
var segLength = pt2.getDistance(pt1); var segLength = pt2.getDistance(pt1),
epsilon *= segLength; eps = epsilon * segLength,
if (alpha1 < epsilon || alpha2 < epsilon) { handle1,
handle2;
if (alpha1 < eps || alpha2 < eps) {
// fall back on standard (probably inaccurate) formula, // fall back on standard (probably inaccurate) formula,
// and subdivide further if needed. // and subdivide further if needed.
alpha1 = alpha2 = segLength / 3; alpha1 = alpha2 = segLength / 3;
} } else {
// Check if the found control points are in the right order when
// Check if the found control points are in the right order when // projected onto the line through pt1 and pt2.
// projected onto the line through pt1 and pt2. var line = pt2.subtract(pt1);
var line = pt2.subtract(pt1),
// Control points 1 and 2 are positioned an alpha distance out // Control points 1 and 2 are positioned an alpha distance out
// on the tangent vectors, left and right, respectively // on the tangent vectors, left and right, respectively
cp1Delta = tan1.normalize(alpha1), handle1 = tan1.normalize(alpha1);
cp2Delta = tan2.normalize(alpha2); handle2 = tan2.normalize(alpha2);
if (cp1Delta.dot(line) - cp2Delta.dot(line) > segLength * segLength) { if (handle1.dot(line) - handle2.dot(line) > segLength * segLength) {
// Fall back to the Wu/Barsky heuristic above. // Fall back to the Wu/Barsky heuristic above.
alpha1 = alpha2 = segLength / 3; alpha1 = alpha2 = segLength / 3;
cp1Delta = tan1.normalize(alpha1); handle1 = handle2 = null; // Force recalculation
cp2Delta = tan2.normalize(alpha2); }
} }
// First and last control points of the Bezier curve are // First and last control points of the Bezier curve are
// positioned exactly at the first and last data points // positioned exactly at the first and last data points
return [pt1, pt1.add(cp1Delta), pt2.add(cp2Delta), pt2]; return [pt1, pt1.add(handle1 || tan1.normalize(alpha1)),
pt2.add(handle2 || tan2.normalize(alpha2)), pt2];
}, },
// Given set of points and their parameterization, try to find // Given set of points and their parameterization, try to find
@ -205,12 +207,10 @@ var PathFitter = Base.extend({
u[i - first] = this.findRoot(curve, this.points[i], u[i - first]); u[i - first] = this.findRoot(curve, this.points[i], u[i - first]);
} }
// Detect if the new parameterization has reordered the points. // Detect if the new parameterization has reordered the points.
// In that case, we would fit the points of the path in the // In that case, we would fit the points of the path in the wrong order.
// wrong order. for (var i = 1, l = u.length; i < l; i++) {
for (var j = 1, jLen = u.length; j < jLen; j++) { if (u[i] <= u[i - 1])
if (u[j] <= u[j - 1]) { return false;
return false;
}
} }
return true; return true;
}, },