title: How to erase an area in a BitmapData object?
body: <p>Flex 3, ActionScript 3, Flash player 9.</p>
  
  <p>I have a picture in a BitmapData object. And an array of points. I nead to erase the part of the picture inside a polygon specified by the points. In other words, draw a polygon specified by the points and fill it with transparency.</p>
  
  <p>Any ideas on how it can be done?</p>