From 3a7c5286b51847a2c9d270036901185147fe6ace Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=BCrg=20Lehni?= <juerg@scratchdisk.com>
Date: Thu, 28 Jul 2011 11:03:59 +0100
Subject: [PATCH] Improve precision of Line#intersect() and other parts that
 check for a divisor to not be 0, by comparing against the new
 Numerical.EPSILON rather than Numerical.TOLERANCE.

---
 src/basic/Line.js      | 3 ++-
 src/path/PathFitter.js | 2 +-
 src/util/Numerical.js  | 3 +++
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/basic/Line.js b/src/basic/Line.js
index 59481a66..3f74d033 100644
--- a/src/basic/Line.js
+++ b/src/basic/Line.js
@@ -74,7 +74,8 @@ var Line = this.Line = Base.extend(/** @lends Line# */{
 	 */
 	intersect: function(line) {
 		var cross = this.vector.cross(line.vector);
-		if (Math.abs(cross) <= Numerical.TOLERANCE)
+		// Avoid divisions by 0, and errors when getting too close to 0
+		if (Math.abs(cross) <= Numerical.EPSILON)
 			return null;
 		var v = line.point.subtract(this.point),
 			t1 = v.cross(line.vector) / cross,
diff --git a/src/path/PathFitter.js b/src/path/PathFitter.js
index 6d012509..a9470220 100644
--- a/src/path/PathFitter.js
+++ b/src/path/PathFitter.js
@@ -93,7 +93,7 @@ var PathFitter = Base.extend({
 
 	// Use least-squares method to find Bezier control points for region.
 	generateBezier: function(first, last, uPrime, tan1, tan2) {
-		var epsilon = Numerical.TOLERANCE,
+		var epsilon = Numerical.EPSILON,
 			pt1 = this.points[first],
 			pt2 = this.points[last],
 			// Create the C and X matrices
diff --git a/src/util/Numerical.js b/src/util/Numerical.js
index 64e97861..043e4ac7 100644
--- a/src/util/Numerical.js
+++ b/src/util/Numerical.js
@@ -63,6 +63,9 @@ var Numerical = new function() {
 
 	return {
 		TOLERANCE: 10e-6,
+		// Precision when comparing against 0
+		// TODO: Find a good value
+		EPSILON: 10e-12,
 
 		/**
 		 * Gauss-Legendre Numerical Integration