Added support for per-property easing

src/fx.js

@@ -128,6 +128,11 @@ jQuery.fn.extend({
 					// Make sure that nothing sneaks out
 					opt.overflow = this.style.overflow;
 				}
+				if ( jQuery.isArray( prop[p] ) ) {
+					// Create (if needed) and add to specialEasing
+					(opt.specialEasing = opt.specialEasing || {})[p] = prop[p][1];
+					prop[p] = prop[p][0];
+				}
 			}
 
 			if ( opt.overflow != null ) {
@@ -387,7 +392,9 @@ jQuery.fx.prototype = {
 			this.state = n / this.options.duration;
 
 			// Perform the easing function, defaults to swing
-			this.pos = jQuery.easing[this.options.easing || (jQuery.easing.swing ? "swing" : "linear")](this.state, n, 0, 1, this.options.duration);
+			var specialEasing = this.options.specialEasing && this.options.specialEasing[this.prop];
+			var defaultEasing = this.options.easing || (jQuery.easing.swing ? "swing" : "linear");
+			this.pos = jQuery.easing[specialEasing || defaultEasing](this.state, n, 0, 1, this.options.duration);
 			this.now = this.start + ((this.end - this.start) * this.pos);
 
 			// Perform the next step of the animation

test/unit/fx.js

@@ -586,3 +586,37 @@ test("jQuery.show('fast') doesn't clear radio buttons (bug #1095)", function ()
   	start();
 	});
 });
+
+test("animate with per-property easing", function(){
+
+	expect(3);
+	stop();
+
+	var _test1_called = false;
+	var _test2_called = false;
+	var _default_test_called = false;
+
+	jQuery.easing['_test1'] = function() {
+		_test1_called = true;
+	};
+
+	jQuery.easing['_test2'] = function() {
+		_test2_called = true;
+	};
+
+	jQuery.easing['_default_test'] = function() {
+		_default_test_called = true;
+	};
+
+	jQuery({a:0,b:0,c:0}).animate({
+		a: [100, '_test1'],
+		b: [100, '_test2'],
+		c: 100
+	}, 400, '_default_test', function(){
+		start();
+		ok(_test1_called, "Easing function (1) called");
+		ok(_test2_called, "Easing function (2) called");
+		ok(_default_test_called, "Easing function (_default) called");
+	});
+
+});