Merge pull request #11074 from osmandapp/FixDownloadButton

Fix algorithm to check one region is inside another

OsmAnd-java/src/main/java/net/osmand/map/OsmandRegions.java

@@ -436,7 +436,7 @@ public class OsmandRegions {
 			cx /= object.getPointsLength();
 			cy /= object.getPointsLength();
 			rd.regionCenter = new LatLon(MapUtils.get31LatitudeY((int) cy), MapUtils.get31LongitudeX((int) cx));
-			rd.boundingBox = findBoundingBox(object);
+			findBoundaries(rd, object);
 		}
 
 		rd.regionParentFullName = mapIndexFields.get(mapIndexFields.parentFullName, object);
@@ -462,13 +462,15 @@ public class OsmandRegions {
 		return rd;
 	}
 
-	private QuadRect findBoundingBox(BinaryMapDataObject object) {
+	private void findBoundaries(WorldRegion rd, BinaryMapDataObject object) {
 		if (object.getPointsLength() == 0) {
-			return new QuadRect(0, 0, 0, 0);
+			return;
 		}
 
+		List<LatLon> polygon = new ArrayList<>();
 		double currentX = object.getPoint31XTile(0);
 		double currentY = object.getPoint31YTile(0);
+		polygon.add(new LatLon(currentX, currentY));
 		double minX = currentX;
 		double maxX = currentX;
 		double minY = currentY;
@@ -488,6 +490,7 @@ public class OsmandRegions {
 				} else if (currentY < minY) {
 					minY = currentY;
 				}
+				polygon.add(new LatLon(currentX, currentY));
 			}
 		}
 
@@ -496,7 +499,8 @@ public class OsmandRegions {
 		double revertedMinY = MapUtils.get31LatitudeY((int) maxY);
 		double revertedMaxY = MapUtils.get31LatitudeY((int) minY);
 
-		return new QuadRect(minX, revertedMinY, maxX, revertedMaxY);
+		rd.boundingBox = new QuadRect(minX, revertedMinY, maxX, revertedMaxY);
+		rd.polygon = polygon;
 	}
 
 	private String getSearchIndex(BinaryMapDataObject object) {

OsmAnd-java/src/main/java/net/osmand/map/WorldRegion.java

@@ -42,6 +42,7 @@ public class WorldRegion implements Serializable {
 	protected boolean regionMapDownload;
 	protected LatLon regionCenter;
 	protected QuadRect boundingBox;
+	protected List<LatLon> polygon;
 
 	public static class RegionParams {
 		protected String regionLeftHandDriving;
@@ -186,12 +187,23 @@ public class WorldRegion implements Serializable {
 	}
 
 	public boolean containsRegion(WorldRegion region) {
-		if (this.boundingBox != null && region.boundingBox != null) {
+		if (containsBoundingBox(region.boundingBox)) {
-			return this.boundingBox.contains(region.boundingBox);
+			// check polygon only if bounding box match
+			return containsPolygon(region.polygon);
 		}
 		return false;
 	}
 
+	private boolean containsBoundingBox(QuadRect rectangle) {
+		return (boundingBox != null && rectangle != null) &&
+				boundingBox.contains(rectangle);
+	}
+
+	private boolean containsPolygon(List<LatLon> another) {
+		return (polygon != null && another != null) &&
+				Algorithms.isFirstPolygonInsideSecond(another, polygon);
+	}
+
 	public boolean isContinent() {
 		if (superregion != null) {
 			String superRegionId = superregion.getRegionId();

OsmAnd-java/src/main/java/net/osmand/util/Algorithms.java

@@ -2,6 +2,7 @@ package net.osmand.util;
 
 import net.osmand.IProgress;
 import net.osmand.PlatformUtil;
+import net.osmand.data.LatLon;
 
 import org.apache.commons.logging.Log;
 import org.xmlpull.v1.XmlPullParser;
@@ -117,6 +118,35 @@ public class Algorithms {
 		}
 		return def;
 	}
+
+	public static boolean isFirstPolygonInsideSecond(List<LatLon> firstPolygon,
+	                                                 List<LatLon> secondPolygon) {
+		for (LatLon point : firstPolygon) {
+			if (!isPointInsidePolygon(point, secondPolygon)) {
+				// if at least one point is not inside the boundary, return false
+				return false;
+			}
+		}
+		return true;
+	}
+
+	public static boolean isPointInsidePolygon(LatLon point,
+	                                           List<LatLon> polygon) {
+		double pointX = point.getLongitude();
+		double pointY = point.getLatitude();
+		boolean result = false;
+		for (int i = 0, j = polygon.size() - 1; i < polygon.size(); j = i++) {
+			double x1 = polygon.get(i).getLongitude();
+			double y1 = polygon.get(i).getLatitude();
+			double x2 = polygon.get(j).getLongitude();
+			double y2 = polygon.get(j).getLatitude();
+			if ((y1 > pointY) != (y2 > pointY)
+					&& (pointX < (x2 - x1) * (pointY - y1) / (y2-y1) + x1)) {
+				result = !result;
+			}
+		}
+		return result;
+	}
 	
 	public static int parseIntSilently(String input, int def) {
 		if (input != null && input.length() > 0) {