GeoTools: Add a polygon complex/simple test in PolygonTools

Core/src/org/droidplanner/core/helpers/geoTools/PolygonTools.java

@@ -1,31 +1,59 @@
 package org.droidplanner.core.helpers.geoTools;
 
 import java.util.ArrayList;
+import java.util.List;
 
 import org.droidplanner.core.helpers.coordinates.Coord2D;
 import org.droidplanner.core.polygon.Polygon;
 
 public class PolygonTools {
 
-	public static Polygon offsetPolygon(Polygon polygon) {
-		ArrayList<LineCoord2D> offsetLines = new ArrayList<LineCoord2D>();		
+	public static Polygon offsetPolygon(Polygon polygon) throws Exception {
+		if (!PolygonTools.isSimplePolygon(polygon)) {
+			throw new Exception("Complex Polygon");
+		}
+
+		ArrayList<LineCoord2D> offsetLines = new ArrayList<LineCoord2D>();
 		for (LineCoord2D line : polygon.getLines()) {
-			offsetLines.add(LineTools.getParallelLineToTheLeft(line,10));
+			offsetLines.add(LineTools.getParallelLineToTheLeft(line, 10));
 		}
-		
+
 		ArrayList<Coord2D> path = new ArrayList<Coord2D>();
 		offsetLines.add(offsetLines.get(0));
 		offsetLines.add(offsetLines.get(1));
 		for (int i = 1; i < offsetLines.size(); i++) {
 			try {
-				path.add(LineTools.FindLineIntersection(offsetLines.get(i-1), offsetLines.get(i),true));
+				path.add(LineTools.FindLineIntersection(offsetLines.get(i - 1), offsetLines.get(i),
+						true));
 			} catch (Exception e) {
 				e.printStackTrace();
-			}			
+			}
 		}
 		Polygon polygonwithOffset = new Polygon();
 		polygonwithOffset.addPoints(path);
 		return polygonwithOffset;
 	}
 
+	public static boolean isSimplePolygon(Polygon polygon) {
+		List<LineCoord2D> lines = polygon.getLines();
+		for (LineCoord2D line1 : lines) {
+			for (LineCoord2D line2 : lines) {
+				if (line1.equals(line2)) {
+					continue;
+				}
+				try{
+					Coord2D intersection = LineTools.FindLineIntersection(line1, line2);
+					if (intersection.equals(line1.getStart())
+							|| intersection.equals(line1.getEnd())
+							|| intersection.equals(line2.getStart())
+							|| intersection.equals(line2.getEnd())) {
+						continue;
+					}
+					return false;
+				} catch (Exception e) {
+				}
+			}
+		}
+		return true;
+	}
 }

Core/test/org/droidplanner/core/helpers/geoTools/PolygonToolsTest.java

@@ -0,0 +1,31 @@
+package org.droidplanner.core.helpers.geoTools;
+
+import org.droidplanner.core.helpers.coordinates.Coord2D;
+import org.droidplanner.core.polygon.Polygon;
+
+import junit.framework.TestCase;
+
+public class PolygonToolsTest extends TestCase {
+
+	public void testIsSimplePolygon() {
+		Polygon polygon = new Polygon();
+
+		polygon.addPoint(new Coord2D(0, 0));
+		polygon.addPoint(new Coord2D(0, 1));
+		polygon.addPoint(new Coord2D(1, 1));
+		polygon.addPoint(new Coord2D(1, 0));
+
+		assertTrue(PolygonTools.isSimplePolygon(polygon));
+	}
+
+	public void testIsComplexPolygon() {
+		Polygon polygon = new Polygon();
+
+		polygon.addPoint(new Coord2D(0, 0));
+		polygon.addPoint(new Coord2D(1, 1));
+		polygon.addPoint(new Coord2D(0, 1));
+		polygon.addPoint(new Coord2D(1, 0));
+
+		assertFalse(PolygonTools.isSimplePolygon(polygon));
+	}
+}