Add ol.control.CenterConstraint

src/ol/control/centerconstraint.js

@@ -0,0 +1,46 @@
+goog.provide('ol.control.CenterConstraint');
+goog.provide('ol.control.CenterConstraintType');
+
+goog.require('ol.Coordinate');
+
+
+/**
+ * @typedef {function((ol.Coordinate|undefined),
+ *                    (number|undefined),
+ *                    ol.Coordinate): (ol.Coordinate|undefined)}
+ */
+ol.control.CenterConstraintType;
+
+
+/**
+ * @param {ol.Coordinate|undefined} center Center.
+ * @param {number|undefined} resolution Resolution.
+ * @param {ol.Coordinate} delta Delta.
+ * @return {ol.Coordinate|undefined} Center.
+ */
+ol.control.CenterConstraint.none = function(center, resolution, delta) {
+  if (goog.isDefAndNotNull(center) && goog.isDef(resolution)) {
+    var x = center.x + delta.x;
+    var y = center.y + delta.y;
+    return new ol.Coordinate(x, y);
+  } else {
+    return undefined;
+  }
+};
+
+
+/**
+ * @param {ol.Coordinate|undefined} center Center.
+ * @param {number|undefined} resolution Resolution.
+ * @param {ol.Coordinate} delta Delta.
+ * @return {ol.Coordinate|undefined} Center.
+ */
+ol.control.CenterConstraint.snapToPixel = function(center, resolution, delta) {
+  if (goog.isDefAndNotNull(center) && goog.isDef(resolution)) {
+    var x = Math.floor((center.x + delta.x) / resolution + 0.5) * resolution;
+    var y = Math.floor((center.y + delta.y) / resolution + 0.5) * resolution;
+    return new ol.Coordinate(x, y);
+  } else {
+    return undefined;
+  }
+};

src/ol/control/control.js

@@ -1,4 +1,3 @@
-// FIXME add snap-to-pixel pan strategy
 // FIXME factor out key precondition (shift et. al)
 
 goog.provide('ol.Control');