scratchfoundation/paper.js
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Merge branch 'fix-simplify-bug' into develop

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Jürg Lehni 2015-04-04 15:54:58 +02:00
commit faecea3955
1 changed files with 31 additions and 10 deletions
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41
src/path/PathFitter.js
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@ -80,13 +80,14 @@ var PathFitter = Base.extend({
// Parameterize points, and attempt to fit curve
var uPrime = this.chordLengthParameterize(first, last),
maxError = Math.max(this.error, this.error * this.error),
split;
split,
parametersInOrder = true;
// Try 4 iterations
for (var i = 0; i <= 4; i++) {
var curve = this.generateBezier(first, last, uPrime, tan1, tan2);
// Find max deviation of points to fitted curve
var max = this.findMaxError(first, last, curve, uPrime);
if (max.error < this.error) {
if (max.error < this.error && parametersInOrder) {
this.addCurve(curve);
return;
}
@ -94,7 +95,7 @@ var PathFitter = Base.extend({
// If error not too large, try reparameterization and iteration
if (max.error >= maxError)
break;
this.reparameterize(first, last, uPrime, curve);
parametersInOrder = this.reparameterize(first, last, uPrime, curve);
maxError = max.error;
}
// Fitting failed -- split at max error point and fit recursively
@ -170,20 +171,33 @@ var PathFitter = Base.extend({
// If alpha negative, use the Wu/Barsky heuristic (see text)
// (if alpha is 0, you get coincident control points that lead to
// divide by zero in any subsequent NewtonRaphsonRootFind() call.
var segLength = pt2.getDistance(pt1);
epsilon *= segLength;
if (alpha1 < epsilon || alpha2 < epsilon) {
var segLength = pt2.getDistance(pt1),
eps = epsilon * segLength,
handle1,
handle2;
if (alpha1 < eps || alpha2 < eps) {
// fall back on standard (probably inaccurate) formula,
// and subdivide further if needed.
alpha1 = alpha2 = segLength / 3;
} else {
// Check if the found control points are in the right order when
// projected onto the line through pt1 and pt2.
var line = pt2.subtract(pt1);
// Control points 1 and 2 are positioned an alpha distance out
// on the tangent vectors, left and right, respectively
handle1 = tan1.normalize(alpha1);
handle2 = tan2.normalize(alpha2);
if (handle1.dot(line) - handle2.dot(line) > segLength * segLength) {
// Fall back to the Wu/Barsky heuristic above.
alpha1 = alpha2 = segLength / 3;
handle1 = handle2 = null; // Force recalculation
}
}
// First and last control points of the Bezier curve are
// positioned exactly at the first and last data points
// Control points 1 and 2 are positioned an alpha distance out
// on the tangent vectors, left and right, respectively
return [pt1, pt1.add(tan1.normalize(alpha1)),
pt2.add(tan2.normalize(alpha2)), 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
@ -192,6 +206,13 @@ var PathFitter = Base.extend({
for (var i = first; i <= last; i++) {
u[i - first] = this.findRoot(curve, this.points[i], u[i - first]);
}
// Detect if the new parameterization has reordered the points.
// In that case, we would fit the points of the path in the wrong order.
for (var i = 1, l = u.length; i < l; i++) {
if (u[i] <= u[i - 1])
return false;
}
return true;
},
// Use Newton-Raphson iteration to find better root.