Get hit candidates from RTree, then refine result

Now we get exact hits also for lines and polygons.

src/ol/geom/base.js

@@ -1,6 +1,8 @@
 goog.provide('ol.geom.Vertex');
 goog.provide('ol.geom.VertexArray');
 
+goog.require('ol.coordinate');
+
 
 /**
  * @typedef {Array.<number>}
@@ -12,3 +14,59 @@ ol.geom.Vertex;
  * @typedef {Array.<ol.geom.Vertex>}
  */
 ol.geom.VertexArray;
+
+
+/**
+ * Calculate the squared distance from a point to a line segment.
+ *
+ * @param {ol.Coordinate} coordinate Coordinate of the point.
+ * @param {Array.<ol.Coordinate>} segment Line segment (2 coordinates).
+ * @return {number} Squared distance from the point to the line segment.
+ */
+ol.geom.squaredDistanceToSegment = function(coordinate, segment) {
+  // http://de.softuses.com/103478, Kommentar #1
+  var v = segment[0];
+  var w = segment[1];
+  var l2 = ol.coordinate.squaredDistance(v, w);
+  if (l2 == 0) {
+    return ol.coordinate.squaredDistance(coordinate, v);
+  }
+  var t = ((coordinate[0] - v[0]) * (w[0] - v[0]) +
+      (coordinate[1] - v[1]) * (w[1] - v[1])) / l2;
+  if (t < 0) {
+    return ol.coordinate.squaredDistance(coordinate, v);
+  }
+  if (t > 1) {
+    return ol.coordinate.squaredDistance(coordinate, w);
+  }
+  return ol.coordinate.squaredDistance(coordinate,
+      [v[0] + t * (w[0] - v[0]), v[1] + t * (w[1] - v[1])]);
+};
+
+
+/**
+ * Calculate whether a point falls inside a polygon.
+ *
+ * @param {ol.Coordinate} coordinate Coordinate of the point.
+ * @param {Array.<ol.Coordinate>} vertices Vertices of the polygon.
+ * @return {boolean} Whether the point falls inside the polygon.
+ */
+ol.geom.pointInPolygon = function(coordinate, vertices) {
+  // http://www.ecse.rpi.edu/Homepages/wrf/Research/Short_Notes/pnpoly.html
+  var x = coordinate[0], y = coordinate[1];
+  var inside = false;
+  var xi, yi, xj, yj, intersect;
+  var numVertices = vertices.length;
+  for (var i = 0, j = numVertices - 1; i < numVertices; j = i++) {
+    xi = vertices[i][0];
+    yi = vertices[i][1];
+    xj = vertices[j][0];
+    yj = vertices[j][1];
+    intersect = ((yi > y) != (yj > y)) &&
+        (x < (xj - xi) * (y - yi) / (yj - yi) + xi);
+    if (intersect) {
+      inside = !inside;
+    }
+  }
+  return inside;
+};