Add ol.CenterConstraint

src/ol/centerconstraint.js

@@ -0,0 +1,42 @@
+goog.provide('ol.CenterConstraint');
+goog.provide('ol.CenterConstraintType');
+
+goog.require('goog.math');
+
+
+/**
+ * @typedef {function((ol.Coordinate|undefined)): (ol.Coordinate|undefined)}
+ */
+ol.CenterConstraintType;
+
+
+/**
+ * @param {ol.Extent} extent Extent.
+ * @return {ol.CenterConstraintType}
+ */
+ol.CenterConstraint.createExtent = function(extent) {
+  return (
+      /**
+       * @param {ol.Coordinate|undefined} center Center.
+       * @return {ol.Coordinate|undefined} Center.
+       */
+      function(center) {
+        if (goog.isDef(center)) {
+          return [
+            goog.math.clamp(center[0], extent[0], extent[2]),
+            goog.math.clamp(center[1], extent[1], extent[3])
+          ];
+        } else {
+          return undefined;
+        }
+      });
+};
+
+
+/**
+ * @param {ol.Coordinate|undefined} center Center.
+ * @return {ol.Coordinate|undefined} Center.
+ */
+ol.CenterConstraint.none = function(center) {
+  return center;
+};