Add optional parameter for result rounding in L.PolyUtil.clipPolygon and L.LineUtil.clipSegment

spec/suites/geometry/LineUtilSpec.js

@@ -33,6 +33,21 @@ describe('LineUtil', function () {
 
 			expect(segment).to.be(false);
 		});
+		
+		it('can round numbers in clipped bounds', function () {
+			var a = new L.Point(4, 5);
+			var b = new L.Point(8, 6);
+			
+			var segment1 = L.LineUtil.clipSegment(a, b, bounds);
+			
+			expect(segment1[0]).to.eql(new L.Point(5, 5.25));
+			expect(segment1[1]).to.eql(b);
+			
+			var segment2 = L.LineUtil.clipSegment(a, b, bounds, false, true);
+			
+			expect(segment2[0]).to.eql(new L.Point(5, 5));
+			expect(segment2[1]).to.eql(b);
+		});
 	});
 
 	describe('#pointToSegmentDistance & #closestPointOnSegment', function () {

spec/suites/geometry/PolyUtilSpec.js

@@ -10,6 +10,7 @@ describe('PolyUtil', function () {
 				new L.Point(10, 15)
 			];
 
+			//check clip without rounding
 			var clipped = L.PolyUtil.clipPolygon(points, bounds);
 
 			for (var i = 0, len = clipped.length; i < len; i++) {
@@ -17,6 +18,20 @@ describe('PolyUtil', function () {
 			}
 
 			expect(clipped).to.eql([
+				new L.Point(7.5, 10),
+				new L.Point(5, 5),
+				new L.Point(10, 7.5),
+				new L.Point(10, 10)
+			]);
+
+			//check clip with rounding
+			var clippedRounded = L.PolyUtil.clipPolygon(points, bounds, true);
+
+			for (i = 0, len = clippedRounded.length; i < len; i++) {
+				delete clippedRounded[i]._code;
+			}
+
+			expect(clippedRounded).to.eql([
 				new L.Point(8, 10),
 				new L.Point(5, 5),
 				new L.Point(10, 8),

src/geometry/LineUtil.js

@@ -99,7 +99,7 @@ L.LineUtil = {
 	// Cohen-Sutherland line clipping algorithm.
 	// Used to avoid rendering parts of a polyline that are not currently visible.
 
-	clipSegment: function (a, b, bounds, useLastCode) {
+	clipSegment: function (a, b, bounds, useLastCode, round) {
 		var codeA = useLastCode ? this._lastCode : this._getBitCode(a, bounds),
 		    codeB = this._getBitCode(b, bounds),
 
@@ -118,7 +118,7 @@ L.LineUtil = {
 			// other cases
 			} else {
 				codeOut = codeA || codeB;
-				p = this._getEdgeIntersection(a, b, codeOut, bounds);
+				p = this._getEdgeIntersection(a, b, codeOut, bounds, round);
 				newCode = this._getBitCode(p, bounds);
 
 				if (codeOut === codeA) {
@@ -132,7 +132,7 @@ L.LineUtil = {
 		}
 	},
 
-	_getEdgeIntersection: function (a, b, code, bounds) {
+	_getEdgeIntersection: function (a, b, code, bounds, round) {
 		var dx = b.x - a.x,
 		    dy = b.y - a.y,
 		    min = bounds.min,
@@ -156,7 +156,7 @@ L.LineUtil = {
 			y = a.y + dy * (min.x - a.x) / dx;
 		}
 
-		return new L.Point(x, y, true);
+		return new L.Point(x, y, round);
 	},
 
 	_getBitCode: function (/*Point*/ p, bounds) {

src/geometry/PolyUtil.js

@@ -10,7 +10,7 @@ L.PolyUtil = {};
  * Sutherland-Hodgeman polygon clipping algorithm.
  * Used to avoid rendering parts of a polygon that are not currently visible.
  */
-L.PolyUtil.clipPolygon = function (points, bounds) {
+L.PolyUtil.clipPolygon = function (points, bounds, round) {
 	var clippedPoints,
 	    edges = [1, 4, 2, 8],
 	    i, j, k,
@@ -35,7 +35,7 @@ L.PolyUtil.clipPolygon = function (points, bounds) {
 			if (!(a._code & edge)) {
 				// if b is outside the clip window (a->b goes out of screen)
 				if (b._code & edge) {
-					p = lu._getEdgeIntersection(b, a, edge, bounds);
+					p = lu._getEdgeIntersection(b, a, edge, bounds, round);
 					p._code = lu._getBitCode(p, bounds);
 					clippedPoints.push(p);
 				}
@@ -43,7 +43,7 @@ L.PolyUtil.clipPolygon = function (points, bounds) {
 
 			// else if b is inside the clip window (a->b enters the screen)
 			} else if (!(b._code & edge)) {
-				p = lu._getEdgeIntersection(b, a, edge, bounds);
+				p = lu._getEdgeIntersection(b, a, edge, bounds, round);
 				p._code = lu._getBitCode(p, bounds);
 				clippedPoints.push(p);
 			}

src/layer/vector/Polygon.js

@@ -58,7 +58,7 @@ L.Polygon = L.Polyline.extend({
 		this._parts = [];
 
 		for (var i = 0, len = this._rings.length, clipped; i < len; i++) {
-			clipped = L.PolyUtil.clipPolygon(this._rings[i], bounds);
+			clipped = L.PolyUtil.clipPolygon(this._rings[i], bounds, true);
 			if (clipped.length) {
 				this._parts.push(clipped);
 			}

src/layer/vector/Polyline.js

@@ -179,7 +179,7 @@ L.Polyline = L.Path.extend({
 			points = this._rings[i];
 
 			for (j = 0, len2 = points.length; j < len2 - 1; j++) {
-				segment = L.LineUtil.clipSegment(points[j], points[j + 1], bounds, j);
+				segment = L.LineUtil.clipSegment(points[j], points[j + 1], bounds, j, true);
 
 				if (!segment) { continue; }