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Some minor adjustments for #1530

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This commit is contained in:
Jürg Lehni 2018-10-05 10:01:51 +02:00
parent c235d6a917
commit f5366fb3cb
3 changed files with 23 additions and 25 deletions
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2
examples/Scripts/PathTangentsToVector.html → examples/Scripts/PathTangents.html
View file

@ -2,7 +2,7 @@
<html>
<head>
<meta charset="UTF-8">
<title>Path Tangents To Vector</title>
<title>Path Tangents</title>
<link rel="stylesheet" href="../css/style.css">
<script type="text/javascript" src="../../dist/paper-full.js"></script>
<script type="text/paperscript" canvas="canvas">

30
src/path/Curve.js
View file

@ -1156,12 +1156,10 @@ statics: /** @lends Curve */{
* tangential to the given tangent
*/
getTimesWithTangent: function (/* tangent */) {
var vector = Point.read(arguments);
if (vector.isZero()) {
return [];
}
return Curve.getTimesWithTangent(this.getValues(), vector);
var tangent = Point.read(arguments);
return tangent.isZero()
? []
: Curve.getTimesWithTangent(this.getValues(), tangent);
},
/**
@ -2253,17 +2251,17 @@ new function() { // Scope for bezier intersection using fat-line clipping
* Tangents at the start or end are included.
*
* @param {Number[]} v curve values
* @param {Point} point the tangent to which the curve must be tangential
* @param {Point} tangent the tangent to which the curve must be tangential
* @return {Number[]} at most two curve-time parameters, where the curve is
* tangential to the given tangent
*/
function getTimesWithTangent(v, point) {
function getTimesWithTangent(v, tangent) {
// Algorithm adapted from: https://stackoverflow.com/a/34837312/7615922
var x0 = v[0], y0 = v[1],
x1 = v[2], y1 = v[3],
x2 = v[4], y2 = v[5],
x3 = v[6], y3 = v[7],
normalized = point.normalize(),
normalized = tangent.normalize(),
tx = normalized.x,
ty = normalized.y,
ax = 3 * x3 - 9 * x2 + 9 * x1 - 3 * x0,
@ -2275,8 +2273,8 @@ new function() { // Scope for bezier intersection using fat-line clipping
den = 2 * ax * ty - 2 * ay * tx,
times = [];
if (Math.abs(den) < Numerical.CURVETIME_EPSILON) {
var num = ax * cy - ay * cx;
var den = ax * by - ay * bx;
var num = ax * cy - ay * cx,
den = ax * by - ay * bx;
if (den != 0) {
var t = -num / den;
if (t >= 0 && t <= 1) times.push(t);
@ -2284,12 +2282,12 @@ new function() { // Scope for bezier intersection using fat-line clipping
} else {
var delta = (bx * bx - 4 * ax * cx) * ty * ty +
(-2 * bx * by + 4 * ay * cx + 4 * ax * cy) * tx * ty +
(by * by - 4 * ay * cy) * tx * tx;
var k = bx * ty - by * tx;
(by * by - 4 * ay * cy) * tx * tx,
k = bx * ty - by * tx;
if (delta >= 0 && den != 0) {
var d = Math.sqrt(delta);
var t0 = -(k + d) / den;
var t1 = (-k + d) / den;
var d = Math.sqrt(delta),
t0 = -(k + d) / den,
t1 = (-k + d) / den;
if (t0 >= 0 && t0 <= 1) times.push(t0);
if (t1 >= 0 && t1 <= 1) times.push(t1);
}

16
src/path/Path.js
View file

@ -2125,9 +2125,9 @@ var Path = PathItem.extend(/** @lends Path# */{
*/
/**
* Calculates path offsets where the path is tangential to provided tangent.
* Note that tangent at start or end are included.
* Tangent at segment point is returned even if only one of its handles is
* Calculates path offsets where the path is tangential to the provided
* tangent. Note that tangents at the start or end are included. Tangents at
* segment points are returned even if only one of their handles is
* collinear with the provided tangent.
*
* @param {Point} tangent the tangent to which the path must be tangential
@ -2141,21 +2141,21 @@ var Path = PathItem.extend(/** @lends Path# */{
}
var offsets = [];
var offsetBeforeCurve = 0;
var curveStart = 0;
var curves = this.getCurves();
for (var i = 0; i < curves.length; i++) {
for (var i = 0, l = curves.length; i < l; i++) {
var curve = curves[i];
// Calculate curves times at vector tangent...
var curveTimes = curve.getTimesWithTangent(tangent);
for (var j = 0; j < curveTimes.length; j++) {
for (var j = 0, m = curveTimes.length; j < m; j++) {
// ...and convert them to path offsets...
var offset = offsetBeforeCurve + curve.getOffsetAtTime(curveTimes[j]);
var offset = curveStart + curve.getOffsetAtTime(curveTimes[j]);
// ...avoiding duplicates.
if (offsets.indexOf(offset) < 0) {
offsets.push(offset);
}
}
offsetBeforeCurve += curve.length;
curveStart += curve.length;
}
return offsets;
}