Improve edge-collision detection of default sprite “arrow” shape

history.txt

@@ -2372,3 +2372,8 @@ ______
 141202
 ------
 * New Kannada translation. Yay!! Thanks, Vinayakumar R!!
+
+141203
+------
+* Morphic: Cache actual bounding box of the Pen arrow shape
+* Threads, Objects: Improve edge-collision detection of default sprite “arrow” shape

objects.js

@@ -125,7 +125,7 @@ PrototypeHatBlockMorph*/
 
 // Global stuff ////////////////////////////////////////////////////////
 
-modules.objects = '2014-December-01';
+modules.objects = '2014-December-03';
 
 var SpriteMorph;
 var StageMorph;
@@ -3238,8 +3238,11 @@ SpriteMorph.prototype.setCenter = function (aPoint, justMe) {
 
 SpriteMorph.prototype.nestingBounds = function () {
     // same as fullBounds(), except that it uses "parts" instead of children
-    var result;
-    result = this.bounds;
+    // and special cases the costume-less "arrow" shape's bounding box
+    var result = this.bounds;
+    if (!this.costume && this.penBounds) {
+        result = this.penBounds.translateBy(this.position());
+    }
     this.parts.forEach(function (part) {
         if (part.isVisible) {
             result = result.merge(part.nestingBounds());

threads.js

@@ -83,7 +83,7 @@ ArgLabelMorph, localize, XML_Element, hex_sha512*/
 
 // Global stuff ////////////////////////////////////////////////////////
 
-modules.threads = '2014-November-26';
+modules.threads = '2014-December-03';
 
 var ThreadManager;
 var Process;
@@ -2368,6 +2368,7 @@ Process.prototype.objectTouchingObject = function (thisObj, name) {
     var myself = this,
         those,
         stage,
+        box,
         mouse;
 
     if (this.inputOption(name) === 'mouse-pointer') {
@@ -2379,9 +2380,14 @@ Process.prototype.objectTouchingObject = function (thisObj, name) {
     } else {
         stage = thisObj.parentThatIsA(StageMorph);
         if (stage) {
-            if (this.inputOption(name) === 'edge' &&
-                    !stage.bounds.containsRectangle(thisObj.bounds)) {
-                return true;
+            if (this.inputOption(name) === 'edge') {
+                box = thisObj.bounds;
+                if (!thisObj.costume && thisObj.penBounds) {
+                    box = thisObj.penBounds.translateBy(thisObj.position());
+                }
+                if (!stage.bounds.containsRectangle(box)) {
+                    return true;
+                }
             }
             if (this.inputOption(name) === 'pen trails' &&
                     thisObj.isTouching(stage.penTrailsMorph())) {