Implement PathItem#getIntersections(path) and Curve#getIntersections(curve) using divide-and-conquer approach, and new Curve.getBounds().

src/load.js

@@ -23,7 +23,8 @@ var options = {
 	browser: true,
 	stats: true,
 	version: 'dev',
-	parser: 'acorn'
+	parser: 'acorn',
+	debug: false
 };
 
 // This folder is specified relatively to the lib folder from which prepro.js is

src/path/Curve.js

@@ -313,6 +313,11 @@ var Curve = this.Curve = Base.extend(/** @lends Curve# */{
 		return Curve.getParameter(this.getValues(), point.x, point.y);
 	},
 
+	getIntersections: function(curve) {
+		return Curve._addIntersections(this.getValues(), curve.getValues(),
+				this, []);
+	},
+
 	getCrossings: function(point, roots) {
 		// Implement the crossing number algorithm:
 		// http://en.wikipedia.org/wiki/Point_in_polygon
@@ -340,7 +345,6 @@ var Curve = this.Curve = Base.extend(/** @lends Curve# */{
 	},
 
 	// TODO: getLocation
-	// TODO: getIntersections
 	// TODO: adjustThroughPoint
 
 	/**
@@ -610,6 +614,63 @@ statics: {
 					+ t * t * t * v3,
 					padding);
 		}
+	},
+
+	// We need to provide the original left curve reference to the
+	// #_addIntersections() calls as it is required for the returned
+	// CurveLocation instances.
+	_addIntersections: function(v1, v2, curve, locations) {
+		var bounds1 = Curve.getBounds(v1),
+			bounds2 = Curve.getBounds(v2);
+/*#*/ if (options.debug) {
+		new Path.Rectangle(bounds1).set({
+			strokeColor: 'green',
+			strokeWidth: 0.1
+		});
+		new Path.Rectangle(bounds2).set({
+			strokeColor: 'red',
+			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 (Curve.isFlatEnough(v1) && Curve.isFlatEnough(v2)) {
+				// Treat both curves as lines and see if their parametric
+				// equations interesct.
+/*#*/ if (options.debug) {
+				new Path.Line(v1[0], v1[1], v1[6], v1[7]).set({
+					strokeColor: 'green',
+					strokeWidth: 0.1
+				});
+				new Path.Line(v2[0], v2[1], v2[6], v2[7]).set({
+					strokeColor: 'red',
+					strokeWidth: 0.1
+				});
+/*#*/ }
+				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)
+					locations.push(new CurveLocation(curve, null, point));
+			} else {
+				var v1s = Curve.subdivide(v1),
+					v2s = Curve.subdivide(v2);
+				this._addIntersections(v1s[0], v2s[0], curve, locations);
+				this._addIntersections(v1s[0], v2s[1], curve, locations);
+				this._addIntersections(v1s[1], v2s[0], curve, locations);
+				this._addIntersections(v1s[1], v2s[1], curve, locations);
+			}
+		}
+		return locations;
 	}
 }}, Base.each(['getBounds', 'getStrokeBounds', 'getHandleBounds', 'getRoughBounds'],
 	// Note: Although Curve.getBounds() exists, we are using Path.getBounds() to

src/path/CurveLocation.js

@@ -24,12 +24,12 @@
  * {@link Path#curves} array is also provided.
  *
  * The class is in use in many places, such as
- * {@link Path#getLocationAt(offset)}, Path#getNearestLocation(point), etc.
+ * {@link Path#getLocationAt(offset)}, Path#getNearestLocation(point),
+ * {@link PathItem#getIntersections(path)}, etc.
  */
 CurveLocation = Base.extend(/** @lends CurveLocation# */{
 	// DOCS: CurveLocation class description: add these back when the  mentioned
-	// functioned have been added: {@link Path#split(location)},
-	// {@link PathItem#getIntersections(path)}, etc.
+	// functioned have been added: {@link Path#split(location)}
 	/**
 	 * Creates a new CurveLocation object.
 	 *

src/path/Path.js

@@ -1348,7 +1348,6 @@ var Path = this.Path = PathItem.extend(/** @lends Path# */{
 	// TODO: intersect(item)
 	// TODO: unite(item)
 	// TODO: exclude(item)
-	// TODO: getIntersections(path)
 }, new function() { // Scope for drawing
 
 	// Note that in the code below we're often accessing _x and _y on point

src/path/PathItem.js

@@ -24,14 +24,26 @@
  * @extends Item
  */
 var PathItem = this.PathItem = Item.extend(/** @lends PathItem# */{
+
 	getIntersections: function(path) {
 		// First check the bounds of the two paths. If they don't intersect,
 		// we don't need to iterate through the whole path.
-		if (this.getBounds().intersects(path.getBounds()))
+		if (!this.getBounds().intersects(path.getBounds()))
 			return [];
 		var locations = [],
 			curves1 = this.getCurves(),
-			curves2 = path.getCurves();		
+			curves2 = path.getCurves(),
+			length2 = curves2.length,
+			values2 = [];
+		for (var i = 0; i < length2; i++)
+			values2[i] = curves2[i].getValues();
+		for (var i = 0, l = curves1.length; i < l; i++) {
+			var curve = curves1[i],
+				values1 = curve.getValues();
+			for (var j = 0; j < length2; j++)
+				Curve._addIntersections(values1, values2[j], curve, locations);
+		}
+		return locations;
 	}
 	/**
 	 * Smooth bezier curves without changing the amount of segments or their