From 5b5865d48e42119a06edfc0909b1da814fb8d116 Mon Sep 17 00:00:00 2001
From: Tom Payne <twpayne@gmail.com>
Date: Tue, 21 Jan 2014 07:48:13 +0100
Subject: [PATCH] Add ol.geom.Polygon#getOrientedFlatCoordinates

---
 src/ol/geom/polygon.js            | 32 +++++++++++
 test/spec/ol/geom/polygon.test.js | 94 +++++++++++++++++++++++++++++++
 2 files changed, 126 insertions(+)

diff --git a/src/ol/geom/polygon.js b/src/ol/geom/polygon.js
index 0da2285d5e..937079bf02 100644
--- a/src/ol/geom/polygon.js
+++ b/src/ol/geom/polygon.js
@@ -50,6 +50,18 @@ ol.geom.Polygon = function(coordinates, opt_layout) {
    */
   this.maxDeltaRevision_ = -1;
 
+  /**
+   * @private
+   * @type {number}
+   */
+  this.orientedRevision_ = -1;
+
+  /**
+   * @private
+   * @type {Array.<number>}
+   */
+  this.orientedFlatCoordinates_ = null;
+
   this.setCoordinates(coordinates, opt_layout);
 
 };
@@ -151,6 +163,26 @@ ol.geom.Polygon.prototype.getLinearRings = function() {
 };
 
 
+/**
+ * @return {Array.<number>} Oriented flat coordinates.
+ */
+ol.geom.Polygon.prototype.getOrientedFlatCoordinates = function() {
+  if (this.orientedRevision_ != this.getRevision()) {
+    var flatCoordinates = this.flatCoordinates;
+    if (ol.geom.flat.linearRingsAreOriented(
+        flatCoordinates, 0, this.ends_, this.stride)) {
+      this.orientedFlatCoordinates_ = flatCoordinates;
+    } else {
+      this.orientedFlatCoordinates_ = flatCoordinates.slice();
+      this.orientedFlatCoordinates_.length = ol.geom.flat.orientLinearRings(
+          this.orientedFlatCoordinates_, 0, this.ends_, this.stride);
+    }
+    this.orientedRevision_ = this.getRevision();
+  }
+  return this.orientedFlatCoordinates_;
+};
+
+
 /**
  * @inheritDoc
  */
diff --git a/test/spec/ol/geom/polygon.test.js b/test/spec/ol/geom/polygon.test.js
index a35f473816..96c36b20cc 100644
--- a/test/spec/ol/geom/polygon.test.js
+++ b/test/spec/ol/geom/polygon.test.js
@@ -94,6 +94,29 @@ describe('ol.geom.Polygon', function() {
       expect(polygon.containsCoordinate(insideInner)).to.be(false);
     });
 
+    describe('#getOrientedFlatCoordinates', function() {
+
+      it('reverses the outer ring if necessary', function() {
+        outerRing.reverse();
+        polygon = new ol.geom.Polygon([outerRing, innerRing]);
+        expect(polygon.getOrientedFlatCoordinates()).to.eql(flatCoordinates);
+      });
+
+      it('reverses inner rings if necessary', function() {
+        innerRing.reverse();
+        polygon = new ol.geom.Polygon([outerRing, innerRing]);
+        expect(polygon.getOrientedFlatCoordinates()).to.eql(flatCoordinates);
+      });
+
+      it('reverses all rings if necessary', function() {
+        outerRing.reverse();
+        innerRing.reverse();
+        polygon = new ol.geom.Polygon([outerRing, innerRing]);
+        expect(polygon.getOrientedFlatCoordinates()).to.eql(flatCoordinates);
+      });
+
+    });
+
   });
 
   describe('construct with 3D coordinates', function() {
@@ -142,6 +165,29 @@ describe('ol.geom.Polygon', function() {
       expect(polygon.containsCoordinate(insideInner)).to.be(false);
     });
 
+    describe('#getOrientedFlatCoordinates', function() {
+
+      it('reverses the outer ring if necessary', function() {
+        outerRing.reverse();
+        polygon = new ol.geom.Polygon([outerRing, innerRing]);
+        expect(polygon.getOrientedFlatCoordinates()).to.eql(flatCoordinates);
+      });
+
+      it('reverses inner rings if necessary', function() {
+        innerRing.reverse();
+        polygon = new ol.geom.Polygon([outerRing, innerRing]);
+        expect(polygon.getOrientedFlatCoordinates()).to.eql(flatCoordinates);
+      });
+
+      it('reverses all rings if necessary', function() {
+        outerRing.reverse();
+        innerRing.reverse();
+        polygon = new ol.geom.Polygon([outerRing, innerRing]);
+        expect(polygon.getOrientedFlatCoordinates()).to.eql(flatCoordinates);
+      });
+
+    });
+
   });
 
   describe('construct with 3D coordinates and layout XYM', function() {
@@ -191,6 +237,29 @@ describe('ol.geom.Polygon', function() {
       expect(polygon.containsCoordinate(insideInner)).to.be(false);
     });
 
+    describe('#getOrientedFlatCoordinates', function() {
+
+      it('reverses the outer ring if necessary', function() {
+        outerRing.reverse();
+        polygon = new ol.geom.Polygon([outerRing, innerRing]);
+        expect(polygon.getOrientedFlatCoordinates()).to.eql(flatCoordinates);
+      });
+
+      it('reverses inner rings if necessary', function() {
+        innerRing.reverse();
+        polygon = new ol.geom.Polygon([outerRing, innerRing]);
+        expect(polygon.getOrientedFlatCoordinates()).to.eql(flatCoordinates);
+      });
+
+      it('reverses all rings if necessary', function() {
+        outerRing.reverse();
+        innerRing.reverse();
+        polygon = new ol.geom.Polygon([outerRing, innerRing]);
+        expect(polygon.getOrientedFlatCoordinates()).to.eql(flatCoordinates);
+      });
+
+    });
+
   });
 
   describe('construct with 4D coordinates', function() {
@@ -248,6 +317,31 @@ describe('ol.geom.Polygon', function() {
       expect(polygon.containsCoordinate(insideInner2)).to.be(false);
     });
 
+    describe('#getOrientedFlatCoordinates', function() {
+
+      it('reverses the outer ring if necessary', function() {
+        outerRing.reverse();
+        polygon = new ol.geom.Polygon([outerRing, innerRing1, innerRing2]);
+        expect(polygon.getOrientedFlatCoordinates()).to.eql(flatCoordinates);
+      });
+
+      it('reverses inner rings if necessary', function() {
+        innerRing1.reverse();
+        innerRing2.reverse();
+        polygon = new ol.geom.Polygon([outerRing, innerRing1, innerRing2]);
+        expect(polygon.getOrientedFlatCoordinates()).to.eql(flatCoordinates);
+      });
+
+      it('reverses all rings if necessary', function() {
+        outerRing.reverse();
+        innerRing1.reverse();
+        innerRing2.reverse();
+        polygon = new ol.geom.Polygon([outerRing, innerRing1, innerRing2]);
+        expect(polygon.getOrientedFlatCoordinates()).to.eql(flatCoordinates);
+      });
+
+    });
+
   });
 
   describe('with a simple polygon', function() {