Add more extent functions

src/ol/extent.js

@@ -134,6 +134,50 @@ ol.extent.createOrUpdate = function(minX, minY, maxX, maxY, opt_extent) {
 };
 
 
+/**
+ * @param {ol.Extent=} opt_extent Extent.
+ * @return {ol.Extent} Extent.
+ */
+ol.extent.createOrUpdateEmpty = function(opt_extent) {
+  return ol.extent.createOrUpdate(
+      Infinity, Infinity, -Infinity, -Infinity, opt_extent);
+};
+
+
+/**
+ * @param {ol.Coordinate} coordinate Coordinate.
+ * @param {ol.Extent=} opt_extent Extent.
+ * @return {ol.Extent} Extent.
+ */
+ol.extent.createOrUpdateFromCoordinate = function(coordinate, opt_extent) {
+  var x = coordinate[0];
+  var y = coordinate[1];
+  return ol.extent.createOrUpdate(x, y, x, y, opt_extent);
+};
+
+
+/**
+ * @param {Array.<ol.Coordinate>} coordinates Coordinates.
+ * @param {ol.Extent=} opt_extent Extent.
+ * @return {ol.Extent} Extent.
+ */
+ol.extent.createOrUpdateFromCoordinates = function(coordinates, opt_extent) {
+  var extent = ol.extent.createOrUpdateEmpty(opt_extent);
+  return ol.extent.extendCoordinates(extent, coordinates);
+};
+
+
+/**
+ * @param {Array.<Array.<ol.Coordinate>>} rings Rings.
+ * @param {ol.Extent=} opt_extent Extent.
+ * @return {ol.Extent} Extent.
+ */
+ol.extent.createOrUpdateFromRings = function(rings, opt_extent) {
+  var extent = ol.extent.createOrUpdateEmpty(opt_extent);
+  return ol.extent.extendRings(extent, rings);
+};
+
+
 /**
  * Empties extent in place.
  * @param {ol.Extent} extent Extent.
@@ -201,6 +245,34 @@ ol.extent.extendCoordinate = function(extent, coordinate) {
 };
 
 
+/**
+ * @param {ol.Extent} extent Extent.
+ * @param {Array.<ol.Coordinate>} coordinates Coordinates.
+ * @return {ol.Extent} Extent.
+ */
+ol.extent.extendCoordinates = function(extent, coordinates) {
+  var i, ii;
+  for (i = 0, ii = coordinates.length; i < ii; ++i) {
+    ol.extent.extendCoordinate(extent, coordinates[i]);
+  }
+  return extent;
+};
+
+
+/**
+ * @param {ol.Extent} extent Extent.
+ * @param {Array.<Array.<ol.Coordinate>>} rings Rings.
+ * @return {ol.Extent} Extent.
+ */
+ol.extent.extendRings = function(extent, rings) {
+  var i, ii;
+  for (i = 0, ii = rings.length; i < ii; ++i) {
+    ol.extent.extendCoordinates(extent, rings[i]);
+  }
+  return extent;
+};
+
+
 /**
  * @param {ol.Extent} extent Extent.
  * @param {number} x X.
@@ -362,6 +434,24 @@ ol.extent.normalize = function(extent, coordinate) {
 };
 
 
+/**
+ * @param {ol.Extent} extent Extent.
+ * @param {ol.Extent=} opt_extent Extent.
+ * @return {ol.Extent} Extent.
+ */
+ol.extent.returnOrUpdate = function(extent, opt_extent) {
+  if (goog.isDef(opt_extent)) {
+    opt_extent[0] = extent[0];
+    opt_extent[1] = extent[1];
+    opt_extent[2] = extent[2];
+    opt_extent[3] = extent[3];
+    return opt_extent;
+  } else {
+    return extent;
+  }
+};
+
+
 /**
  * @param {ol.Extent} extent Extent.
  * @param {number} value Value.