Simple Skew Animation with ActionScript 3

I couldn’t find any good examples on simple tween of a skew effect in actionscipt 3 so I thought I’d share what I came up with.

The problem is that skew is not a property on the MovieClip like x or height or others you’re used to tweening with fl.transitions. To apply a skew effect in AS3 you need to use a matrix transform like this:

```    import flash.geom.Matrix;
var matrix:Matrix = new Matrix();
matrix.b = _y * Math.PI/180;
matrix.c = _x * Math.PI/180;
matrix.concat(target.transform.matrix);
my_mc.transform.matrix = matrix;
```

or

```    import flash.geom.Matrix;
var matrix:Matrix = new Matrix(1, _y * Math.PI/180, _x * Math.PI/180, 1, 0, 0);
my_mc.transform.matrix = matrix;
```

where _y or _x is the skew angle in radians. Unfortunately when you update a property of the transform matrix like

`my_mc.transform.matrix.b = _y * Math.PI/180;`

it doesn’t update the movieclip. You need to actually re-assign the matrix to trigger an update. So you can’t simply tween the my_mc.transform.matrix.b directly. Here’s my solution.

```    import fl.transitions.Tween;
import fl.transitions.easing.*;
import fl.transitions.TweenEvent;
import flash.geom.Matrix;

var mymatrix:Matrix = new Matrix(1,0,0,1,0,0);

function reassignMatrix(e:TweenEvent) {
bg.transform.matrix = mymatrix;
}

var bgTweenSkew = new Tween(mymatrix, 'b', Regular.easeOut, mymatrix.b, Math.tan(_y * (Math.PI/180)), 10);