Move ol/geom/flat/areaflatgeom.js to ol/geom/flat/area.js

src/ol/geom/flat/area.js

@@ -0,0 +1,62 @@
+goog.provide('ol.geom.flat.area');
+
+
+/**
+ * @param {Array.<number>} flatCoordinates Flat coordinates.
+ * @param {number} offset Offset.
+ * @param {number} end End.
+ * @param {number} stride Stride.
+ * @return {number} Area.
+ */
+ol.geom.flat.area.linearRing = function(flatCoordinates, offset, end, stride) {
+  var twiceArea = 0;
+  var x1 = flatCoordinates[end - stride];
+  var y1 = flatCoordinates[end - stride + 1];
+  for (; offset < end; offset += stride) {
+    var x2 = flatCoordinates[offset];
+    var y2 = flatCoordinates[offset + 1];
+    twiceArea += y1 * x2 - x1 * y2;
+    x1 = x2;
+    y1 = y2;
+  }
+  return twiceArea / 2;
+};
+
+
+/**
+ * @param {Array.<number>} flatCoordinates Flat coordinates.
+ * @param {number} offset Offset.
+ * @param {Array.<number>} ends Ends.
+ * @param {number} stride Stride.
+ * @return {number} Area.
+ */
+ol.geom.flat.area.linearRings = function(flatCoordinates, offset, ends, stride) {
+  var area = 0;
+  var i, ii;
+  for (i = 0, ii = ends.length; i < ii; ++i) {
+    var end = ends[i];
+    area += ol.geom.flat.area.linearRing(flatCoordinates, offset, end, stride);
+    offset = end;
+  }
+  return area;
+};
+
+
+/**
+ * @param {Array.<number>} flatCoordinates Flat coordinates.
+ * @param {number} offset Offset.
+ * @param {Array.<Array.<number>>} endss Endss.
+ * @param {number} stride Stride.
+ * @return {number} Area.
+ */
+ol.geom.flat.area.linearRingss = function(flatCoordinates, offset, endss, stride) {
+  var area = 0;
+  var i, ii;
+  for (i = 0, ii = endss.length; i < ii; ++i) {
+    var ends = endss[i];
+    area +=
+        ol.geom.flat.area.linearRings(flatCoordinates, offset, ends, stride);
+    offset = ends[ends.length - 1];
+  }
+  return area;
+};