More matrix related clean-ups.

src/basic/Matrix.js

@@ -373,6 +373,10 @@ var Matrix = Base.extend(/** @lends Matrix# */{
 				&& this._tx === 0 && this._ty === 0;
 	},
 
+	orNullIfIdentity: function() {
+		return this.isIdentity() ? null : this;
+	},
+
 	/**
 	 * Returns whether the transform is invertible. A transform is not
 	 * invertible if the determinant is 0 or any value is non-finite or NaN.

src/item/Item.js

@@ -829,7 +829,8 @@ var Item = Base.extend(Callback, /** @lends Item# */{
 		// See if we can cache these bounds. We only cache the bounds
 		// transformed with the internally stored _matrix, (the default if no
 		// matrix is passed).
-		var _matrix = this._matrix,
+		matrix = matrix && matrix.orNullIfIdentity();
+		var _matrix = this._matrix.orNullIfIdentity(),
 			cache = (!matrix || matrix.equals(_matrix)) && getter;
 		// Set up a boundsCache structure that keeps track of items that keep
 		// cached bounds that depend on this item. We store this in our parent,
@@ -862,9 +863,7 @@ var Item = Base.extend(Callback, /** @lends Item# */{
 		// If the result of concatinating the passed matrix with our internal
 		// one is an identity transformation, set it to null for faster
 		// processing
-		if (_matrix.isIdentity())
-			_matrix = null;
-		matrix = !matrix || matrix.isIdentity()
+		matrix = !matrix
 				? _matrix
 				: _matrix
 					? matrix.clone().concatenate(_matrix)

src/path/PathItem.js

@@ -67,14 +67,10 @@ var PathItem = Item.extend(/** @lends PathItem# */{
 		var locations = [],
 			curves1 = this.getCurves(),
 			curves2 = path.getCurves(),
-			matrix1 = this._matrix,
-			matrix2 = path._matrix,
+			matrix1 = this._matrix.orNullIfIdentity(),
+			matrix2 = path._matrix.orNullIfIdentity(),
 			length2 = curves2.length,
 			values2 = [];
-		if (matrix1.isIdentity())
-			matrix1 = null;
-		if (matrix2.isIdentity())
-			matrix2 = null;
 		for (var i = 0; i < length2; i++)
 			values2[i] = curves2[i].getValues(matrix2);
 		for (var i = 0, l = curves1.length; i < l; i++) {