Review comments

Author: kurkle

src/elements/element.line.js

@@ -3,7 +3,7 @@
 import defaults from '../core/core.defaults';
 import Element from '../core/core.element';
 import {_steppedLineTo, _bezierCurveTo} from '../helpers/helpers.canvas';
-import {_angleDiff, _angleDiffCW, _normalizeAngle, _pointInLine, _steppedInterpolation, _bezierInterpolation} from '../helpers/helpers.math';
+import {_angleDiff, _angleDiffPD, _normalizeAngle, _pointInLine, _steppedInterpolation, _bezierInterpolation} from '../helpers/helpers.math';
 
 const defaultColor = defaults.global.defaultColor;
 
@@ -169,7 +169,7 @@ function useFastPath(vm, options) {
 
 function angleBetween(a, s, e) {
 	return a === s || a === e ||
-		(_angleDiffCW(a, s) > _angleDiffCW(a, e) && _angleDiffCW(s, a) < _angleDiffCW(e, a));
+		(_angleDiffPD(a, s) > _angleDiffPD(a, e) && _angleDiffPD(s, a) < _angleDiffPD(e, a));
 }
 
 function propertyFn(property) {

src/helpers/helpers.math.js

@@ -181,22 +181,25 @@ export function _bezierInterpolation(p1, p2, t) {
 }
 
 /**
+ * Shortest distance between agnles, in either direction.
  * @private
  */
 export function _angleDiff(a, b) {
 	return (a - b + PITAU) % TAU - PI;
 }
 
 /**
+ * Normalize angle to be between 0 and 2*PI
  * @private
  */
 export function _normalizeAngle(a) {
-	return (a + TAU) % TAU;
+	return (a % TAU + TAU) % TAU;
 }
 
 /**
+ * Angle difference in positive direction.
  * @private
  */
-export function _angleDiffCW(a, b) {
-	return (_normalizeAngle(b) - _normalizeAngle(a) + TAU) % TAU;
+export function _angleDiffPD(a, b) {
+	return _normalizeAngle(_normalizeAngle(b) - _normalizeAngle(a));
 }