Copying a Flash MovieClip, or The Flash Holy Grail

Posted on Fri 15 May 2009 in Development

Ran into a nice solution for copying arbitrary MovieClips at runtime today. I am designing a spot the difference game akin to 6 Differences with the requirement that, upon finding a difference, the scene should go to the "correct" state depending on which difference was defined as master, among a few other criterion. This required that I somehow duplicate, as much as is possible, the state of the "master" difference, when appropriate. At any rate, the solution comes from Danny Burbol's blog, which apparently came from a Experts Exchange thread (damn people charging for information). I modified the solution a bit to fit my needs, but not by a whole lot. Sometimes I only need to copy the instance and I can reconstitute the MovieClip from there but other times I will need to get the whole shebang. It's pretty handy in general. So my version follows (as a bonus I include my handy-dandy clearAllChildren function):

package com.bmm.utils {
  import flash.display.DisplayObject;
  import flash.display.DisplayObjectContainer;
  import flash.geom.Rectangle;

  /**
   * ...
   * @author BenS
   */
  public class UIUtils {

    public static function clearAllChildren(c:DisplayObjectContainer):void {
      if (c == null || c.numChildren == 0) return;

      var i:int = 0, n:int = c.numChildren;
      for (i = 0; i < n; i++) {
        c.removeChildAt(0);
      }
    }

    public static function simpleDisplayObjectClone(source:DisplayObject):DisplayObject {
      var cc:Class = Object(source).constructor;
      return new cc();
    }

    public static function displayObjectClone(source:DisplayObject):DisplayObject {
      var copy:DisplayObject = UIUtils.simpleDisplayObjectClone(source);

      copy.transform = source.transform;
      copy.filters = source.filters;
      copy.cacheAsBitmap = source.cacheAsBitmap;
      copy.opaqueBackground = source.opaqueBackground;
      if (source.scale9Grid) {
        var r:Rectangle = source.scale9Grid;
        copy.scale9Grid = r;
      }

      return copy;
    }
  }
}