Merge pull request #49 from saebyn/develop

Add inflate methods for rect, fix gh-47

lib/gamejs.js

@@ -209,14 +209,14 @@ objects.accessors(Rect.prototype, {
     */
    'center': {
       get: function() {
-         return [this.left + (this.width / 2),
-                 this.top + (this.height / 2)
+         return [this.left + (this.width / 2) | 0,
+                 this.top + (this.height / 2) | 0
                 ];
       },
       set: function() {
          var args = normalizeRectArguments.apply(this, arguments);
-         this.left = args.left - (this.width / 2);
-         this.top = args.top - (this.height / 2);
+         this.left = args.left - (this.width / 2) | 0;
+         this.top = args.top - (this.height / 2) | 0;
          return;
       }
    },
@@ -402,6 +402,36 @@ Rect.prototype.union = function(rect) {
    return new Rect(x, y, width, height);
 };
 
+/**
+ * Grow or shrink the rectangle size
+ *
+ * @param {Number} amount to change in the width
+ * @param {Number} amount to change in the height
+ * @returns {gamejs.Rect} inflated rectangle centered on the original rectangle's center
+ */
+Rect.prototype.inflate = function(x, y) {
+    var copy = this.clone();
+
+    copy.inflateIp(x, y);
+
+    return copy;
+}
+
+/**
+ * Grow or shrink this Rect in place - not returning a new Rect like `inflate(x, y)` would.
+ *
+ * @param {Number} amount to change in the width
+ * @param {Number} amount to change in the height
+ */
+Rect.prototype.inflateIp = function(x, y) {
+    // Use Math.floor here to deal with rounding of negative numbers the
+    // way this relies on.
+    this.left -= Math.floor(x / 2);
+    this.top -= Math.floor(y / 2);
+    this.width += x;
+    this.height += y;
+}
+
 /**
  * Check for collision with a point.
  *

lib/gamejs/time.js

@@ -47,6 +47,10 @@ exports.init = function() {
  * @param {Number} fps specify the framerate by which you want the callback to be called. (e.g. 30 = 30 times per seconds). default: 30
  */
 exports.fpsCallback = function(fn, thisObj, fps) {
+   if ( fps === undefined ) {
+     fps = 30;
+   }
+
    fps = parseInt(1000/fps, 10);
    CALLBACKS[fps] = CALLBACKS[fps] || [];
    CALLBACKS_LASTCALL[fps] = CALLBACKS_LASTCALL[fps] || 0;

tests/rectsurface.js

@@ -31,8 +31,8 @@ test('RectConstructors', function() {
    strictEqual(rect.bottom, top + height);
    strictEqual(rect.right, left + width);
    deepEqual(rect.center, [
-      left + width / 2,
-      top + height / 2
+      left + Math.floor(width / 2),
+      top + Math.floor(height / 2)
    ]);
 
    var rect = new gamejs.Rect([left, top, width, height]);
@@ -44,8 +44,8 @@ test('RectConstructors', function() {
    strictEqual(rect.bottom, top + height);
    strictEqual(rect.right, left + width);
    deepEqual(rect.center, [
-      left + width / 2,
-      top + height / 2
+      left + Math.floor(width / 2),
+      top + Math.floor(height / 2)
    ]);
 
    var rect = new gamejs.Rect(left, top, width, height);
@@ -57,8 +57,8 @@ test('RectConstructors', function() {
    strictEqual(rect.bottom, top + height);
    strictEqual(rect.right, left + width);
    deepEqual(rect.center, [
-      left + width / 2,
-      top + height / 2
+      left + Math.floor(width / 2),
+      top + Math.floor(height / 2)
    ]);
 });
 
@@ -115,6 +115,31 @@ test('RectSetters', function() {
 
 });
 
+test('RectInflate', function() {
+   var rect = new gamejs.Rect(0, 0, 10, 10);
+   var newRect = rect.inflate(1, 0);
+   strictEqual(newRect.left, 0);
+   strictEqual(newRect.top, 0);
+   strictEqual(newRect.width, 11);
+   strictEqual(newRect.height, 10);
+
+   rect = new gamejs.Rect(5, 5, 12, 14);
+   newRect = rect.inflate(12, 3);
+   deepEqual(newRect.center, rect.center);
+   newRect = rect.inflate(-3, 3);
+   deepEqual(newRect.center, rect.center);
+   strictEqual(newRect.left, 7);
+   strictEqual(newRect.top, 4);
+   strictEqual(newRect.width, 9);
+   strictEqual(newRect.height, 17);
+
+   rect.inflateIp(-2, -2);
+   strictEqual(rect.left, 6);
+   strictEqual(rect.top, 6);
+   strictEqual(rect.width, 10);
+   strictEqual(rect.height, 12);
+});
+
 test('RectCollide', function() {
    // overlapping
    var rect = new gamejs.Rect(0, 0, 10, 10);