Merge pull request #23 from StefanoSperetta/master

Adding latitude range option

README.md

@@ -33,6 +33,13 @@ points are computed. The step size is 1°/resolution, i.e. higher
 resolution values have smaller step sizes and more points in the
 polygon. The default value is 2.
 
+Leaflet.Terminator computes the terminator from longitudes -360° to +360°
+(a range of 720°), covering the Earth twice. To limit the terminator
+longitude range, the `longitudeRange` option is available.
+
+```js
+var sunlightOverlay = L.terminator({resolution: 5, longitudeRange:360});
+```
 
 You can pass the `time` option in the constructor or use the `setTime()`
 method to control the reference time and date for the terminator; the

index.js

@@ -24,7 +24,8 @@ var Terminator = L.Polygon.extend({
 		opacity: 0.5,
 		fillColor: '#00',
 		fillOpacity: 0.5,
-		resolution: 2
+		resolution: 2,
+		longitudeRange: 720
 	},
 
 	initialize: function (options) {
@@ -118,17 +119,17 @@ var Terminator = L.Polygon.extend({
 		var sunEclPos = this._sunEclipticPosition(julianDay);
 		var eclObliq = this._eclipticObliquity(julianDay);
 		var sunEqPos = this._sunEquatorialPosition(sunEclPos.lambda, eclObliq);
-		for (var i = 0; i <= 720 * this.options.resolution; i++) {
-			var lng = -360 + i / this.options.resolution;
+		for (var i = 0; i <= this.options.longitudeRange * this.options.resolution; i++) {
+			var lng = -this.options.longitudeRange/2 + i / this.options.resolution;
 			var ha = this._hourAngle(lng, sunEqPos, gst);
 			latLng[i + 1] = [this._latitude(ha, sunEqPos), lng];
 		}
 		if (sunEqPos.delta < 0) {
-			latLng[0] = [90, -360];
-			latLng[latLng.length] = [90, 360];
+			latLng[0] = [90, -this.options.longitudeRange/2];
+			latLng[latLng.length] = [90, this.options.longitudeRange/2];
 		} else {
-			latLng[0] = [-90, -360];
-			latLng[latLng.length] = [-90, 360];
+			latLng[0] = [-90, -this.options.longitudeRange/2];
+			latLng[latLng.length] = [-90, this.options.longitudeRange/2];
 		}
 		return latLng;
 	}