From 10e2510f0f119e69fa78a62096453d648a5708d0 Mon Sep 17 00:00:00 2001
From: "Philip \"digitalfox\" Kovac" <pkovac@cs.uml.edu>
Date: Wed, 16 Dec 2015 15:24:58 -0500
Subject: [PATCH] Added boxEndCondition to DragBoxOptions to replace the
 hardcoded check against DRAG_BOX_HYSTERESIS_PIXELS_SQUARED.

---
 externs/olx.js                           | 22 ++++++++++++-
 src/ol/interaction/dragboxinteraction.js | 41 +++++++++++++++++++++---
 2 files changed, 57 insertions(+), 6 deletions(-)

diff --git a/externs/olx.js b/externs/olx.js
index b527195d2f..bec4bc0800 100644
--- a/externs/olx.js
+++ b/externs/olx.js
@@ -2361,7 +2361,8 @@ olx.interaction.DragAndDropOptions.prototype.projection;
 
 /**
  * @typedef {{className: (string|undefined),
- *     condition: (ol.events.ConditionType|undefined)}}
+ *     condition: (ol.events.ConditionType|undefined),
+ *     boxEndCondition: (ol.interaction.DragBoxEndConditionType|undefined)}}
  * @api
  */
 olx.interaction.DragBoxOptions;
@@ -2385,6 +2386,25 @@ olx.interaction.DragBoxOptions.prototype.className;
 olx.interaction.DragBoxOptions.prototype.condition;
 
 
+/**
+ * A function that takes a {@link ol.MapBrowserEvent} and two
+ * {@link ol.Pixel}s to indicate whether a boxend event should be fired.
+ * Default is:
+ * ```js
+ * function(mapBrowserEvent,
+ *     startPixel, endPixel) {
+ *   var width = endPixel[0] - startPixel[0];
+ *   var height = endPixel[1] - startPixel[1];
+ *   return width * width + height * height >=
+ *     ol.DRAG_BOX_HYSTERESIS_PIXELS_SQUARED;
+ * }
+ * ```
+ * @type {ol.interaction.DragBoxEndConditionType|undefined}
+ * @api
+ */
+olx.interaction.DragBoxOptions.prototype.boxEndCondition;
+
+
 /**
  * @typedef {{kinetic: (ol.Kinetic|undefined)}}
  * @api
diff --git a/src/ol/interaction/dragboxinteraction.js b/src/ol/interaction/dragboxinteraction.js
index ca044f1067..0c2988cd16 100644
--- a/src/ol/interaction/dragboxinteraction.js
+++ b/src/ol/interaction/dragboxinteraction.js
@@ -65,6 +65,16 @@ ol.DragBoxEvent = function(type, coordinate) {
 goog.inherits(ol.DragBoxEvent, goog.events.Event);
 
 
+/**
+ * A function that takes a {@link ol.MapBrowserEvent} and two
+ * {@link ol.Pixel}s and returns a `{boolean}`. If the condition is met,
+ * true should be returned.
+ * @typedef {function(ol.MapBrowserEvent, ol.Pixel, ol.Pixel):boolean}
+ * @api
+ */
+ol.interaction.DragBoxEndConditionType;
+
+
 
 /**
  * @classdesc
@@ -112,10 +122,34 @@ ol.interaction.DragBox = function(opt_options) {
   this.condition_ = options.condition ?
       options.condition : ol.events.condition.always;
 
+  /**
+   * @private
+   * @type {ol.interaction.DragBoxEndConditionType}
+   */
+  this.boxEndCondition_ = options.boxEndCondition ?
+      options.boxEndCondition : ol.interaction.DragBox.defaultBoxEndCondition;
 };
 goog.inherits(ol.interaction.DragBox, ol.interaction.Pointer);
 
 
+/**
+ * The default condition for determining whether the boxend event
+ * should fire.
+ * @param  {ol.MapBrowserEvent} mapBrowserEvent The originating MapBrowserEvent
+ *  leading to the box end.
+ * @param  {ol.Pixel} startPixel      The starting pixel of the box.
+ * @param  {ol.Pixel} endPixel        The end pixel of the box.
+ * @return {boolean} Whether or not the boxend condition should be fired.
+ */
+ol.interaction.DragBox.defaultBoxEndCondition = function(mapBrowserEvent,
+    startPixel, endPixel) {
+  var width = endPixel[0] - startPixel[0];
+  var height = endPixel[1] - startPixel[1];
+  return width * width + height * height >=
+      ol.DRAG_BOX_HYSTERESIS_PIXELS_SQUARED;
+};
+
+
 /**
  * @param {ol.MapBrowserPointerEvent} mapBrowserEvent Event.
  * @this {ol.interaction.DragBox}
@@ -162,11 +196,8 @@ ol.interaction.DragBox.handleUpEvent_ = function(mapBrowserEvent) {
 
   this.box_.setMap(null);
 
-  var deltaX = mapBrowserEvent.pixel[0] - this.startPixel_[0];
-  var deltaY = mapBrowserEvent.pixel[1] - this.startPixel_[1];
-
-  if (deltaX * deltaX + deltaY * deltaY >=
-      ol.DRAG_BOX_HYSTERESIS_PIXELS_SQUARED) {
+  if (this.boxEndCondition_(mapBrowserEvent,
+      this.startPixel_, mapBrowserEvent.pixel)) {
     this.onBoxEnd(mapBrowserEvent);
     this.dispatchEvent(new ol.DragBoxEvent(ol.DragBoxEventType.BOXEND,
         mapBrowserEvent.coordinate));