Rename Curve#getParameter(length) -> Curve#getParameterAt(offset)

examples/Scripts/CurveTimeParameterization.html

@@ -39,8 +39,8 @@
 			} else {
 				for (var i = 0, pos = 0; i <= num; i++, pos += step) {
 					var t = iteratively
-							? curve.getParameter(step, prev)
+							? curve.getParameterAt(step, prev)
-							: curve.getParameter(pos);
+							: curve.getParameterAt(pos);
 					var point = curve.getPoint(t);
 					var circle = new Path.Circle(point, step / 2);
 					circle.strokeColor = 'red';

src/path/Curve.js

@@ -253,16 +253,17 @@ var Curve = this.Curve = Base.extend(/** @lends Curve# */{
 	},
 
 	// PORT: Add support for start parameter to Sg
-	// DOCS: document Curve#getParameter(length, start)
+	// PORT: Rename #getParameter(length) -> #getParameterAt(offset)
+	// DOCS: Document #getParameter(length, start)
 	/**
-	 * @param {Number} length
+	 * @param {Number} offset
 	 * @param {Number} [start]
 	 * @return {Number}
 	 */
-	getParameter: function(length, start) {
+	getParameterAt: function(offset, start) {
 		var args = this.getValues();
-		args.push(length, start !== undefined ? start : length < 0 ? 1 : 0);
+		args.push(offset, start !== undefined ? start : offset < 0 ? 1 : 0);
-		return Curve.getParameter.apply(Curve, args);
+		return Curve.getParameterAt.apply(Curve, args);
 	},
 
 	/**
@@ -606,16 +607,16 @@ var Curve = this.Curve = Base.extend(/** @lends Curve# */{
 			return Numerical.integrate(ds, a, b, getIterations(a, b));
 		},
 
-		getParameter: function(p1x, p1y, c1x, c1y, c2x, c2y, p2x, p2y,
+		getParameterAt: function(p1x, p1y, c1x, c1y, c2x, c2y, p2x, p2y,
-				length, start) {
+				offset, start) {
-			if (length == 0)
+			if (offset == 0)
 				return start;
 			// See if we're going forward or backward, and handle cases
 			// differently
-			var forward = length > 0,
+			var forward = offset > 0,
 				a = forward ? start : 0,
 				b = forward ? 1 : start,
-				length = Math.abs(length),
+				offset = Math.abs(offset),
 				// Use integrand to calculate both range length and part
 				// lengths in f(t) below.
 				ds = getLengthIntegrand(
@@ -623,25 +624,23 @@ var Curve = this.Curve = Base.extend(/** @lends Curve# */{
 				// Get length of total range
 				rangeLength = Numerical.integrate(ds, a, b,
 						getIterations(a, b));
-			if (length >= rangeLength)
+			if (offset >= rangeLength)
 				return forward ? b : a;
-			// Use length / rangeLength for an initial guess for t, to
+			// Use offset / rangeLength for an initial guess for t, to
 			// bring us closer:
-			var guess = length / rangeLength,
+			var guess = offset / rangeLength,
-				len = 0;
+				length = 0;
 			// Iteratively calculate curve range lengths, and add them up,
 			// using integration precision depending on the size of the
 			// range. This is much faster and also more precise than not
 			// modifing start and calculating total length each time.
 			function f(t) {
 				var count = getIterations(start, t);
-				if (start < t) {
+				length += start < t
-					len += Numerical.integrate(ds, start, t, count);
+						? Numerical.integrate(ds, start, t, count)
-				} else {
+						: -Numerical.integrate(ds, t, start, count);
-					len -= Numerical.integrate(ds, t, start, count);
-				}
 				start = t;
-				return len - length;
+				return length - offset;
 			}
 			return Numerical.findRoot(f, ds,
 					forward ? a + guess : b - guess, // Initial guess for x
@@ -832,5 +831,5 @@ var Curve = this.Curve = Base.extend(/** @lends Curve# */{
 		getNearestPoint: function(point) {
 			return this.getNearestLocation(point).getPoint();
 		}
-	}
+	};
 });

src/path/CurveLocation.js

@@ -136,7 +136,7 @@ CurveLocation = Base.extend(/** @lends CurveLocation# */{
 	 */
 	getParameter: function() {
 		if (this._parameter == null && this._curve && this._point)
-			this._parameter = this._curve.getParameter(this._point);
+			this._parameter = this._curve.getParameterAt(this._point);
 		return this._parameter;
 	},
 

src/path/Path.js

@@ -960,7 +960,7 @@ var Path = this.Path = PathItem.extend(/** @lends Path# */{
 			if (length >= offset) {
 				// Found the segment within which the length lies
 				return new CurveLocation(curve,
-						curve.getParameter(offset - start));
+						curve.getParameterAt(offset - start));
 			}
 		}
 		// It may be that through impreciseness of getLength, that the end

test/tests/Path_Length.js

@@ -25,7 +25,7 @@ test('path.length', function() {
 	var length = path.length;
 	compareNumbers(length, 172.10122680664062);
 
-	var param = path.curves[0].getParameter(length / 4);
+	var param = path.curves[0].getParameterAt(length / 4);
 	compareNumbers(param, 0.2255849553116685);
 });
 
@@ -35,6 +35,6 @@ test('curve.getParameter with straight curve', function() {
 	path.lineTo(500, 500);
 	var curve = path.curves[0];
 	var length = curve.length;
-	var t = curve.getParameter(length / 3);
+	var t = curve.getParameterAt(length / 3);
 	compareNumbers(t, 0.3869631475722452);
 });