    package flare.animate.interpolate
    {
        import flash.geom.Matrix;

        /**
         * Interpolator for <code>flash.geom.Matrix</code> values.
         */
        public class MatrixInterpolator extends Interpolator
        {
            private var _startA:Number, _startB:Number, _startC:Number;
            private var _startD:Number, _startX:Number, _startY:Number;
            private var _rangeA:Number, _rangeB:Number, _rangeC:Number;
            private var _rangeD:Number, _rangeX:Number, _rangeY:Number;
            private var _cur:Matrix;

            /**
             * Creates a new MatrixInterpolator.
             * @param target the object whose property is being interpolated
             * @param property the property to interpolate
             * @param start the starting matrix value to interpolate from
             * @param end the target matrix value to interpolate to
             */
            public function MatrixInterpolator(target:Object, property:String,
                                               start:Object, end:Object)
            {
                super(target, property, start, end);
            }

            /**
             * Initializes this interpolator.
             * @param start the starting value of the interpolation
             * @param end the target value of the interpolation
             */
            protected override function init(start:Object, end:Object) : void
            {
                var e:Matrix = Matrix(end), s:Matrix = Matrix(start);
                _cur = _prop.getValue(_target) as Matrix;
                if (_cur == null || _cur == s || _cur == e)
                    _cur = e.clone();

                _startA = s.a;
                _startB = s.b;
                _startC = s.c;
                _startD = s.d;
                _startX = s.tx;
                _startY = s.ty;
                _rangeA = e.a  - _startA;
                _rangeB = e.b  - _startB;
                _rangeC = e.c  - _startC;
                _rangeD = e.d  - _startD;
                _rangeX = e.tx - _startX;
                _rangeY = e.ty - _startY;
            }

            /**
             * Calculate and set an interpolated property value.
             * @param f the interpolation fraction (typically between 0 and 1)
             */
            public override function interpolate(f:Number) : void
            {
                _cur.a  = _startA + f * _rangeA;
                _cur.b  = _startB + f * _rangeB;
                _cur.c  = _startC + f * _rangeC;
                _cur.d  = _startD + f * _rangeD;
                _cur.tx = _startX + f * _rangeX;
                _cur.ty = _startY + f * _rangeY;
                _prop.setValue(_target, _cur);
            }

        } // end of class MatrixInterpolator
    }