  * by using Adobe Pixel Bender Toolkit.</p>
  *
  * <p>If either bitmap is
- * not supplied, that value will be determined dynamically from
+ * not supplied, that value is determined dynamically from
  * either the appropriate state of the target in a transition or, 
  * if the effect is not running in a transition, from the 
  * target directly. If
  * the effect is run in a transition and the target object either
  * goes away or comes into existence during that state change,
- * then a fully-transparent bitmap will be used to represent
+ * then a fully-transparent bitmap is used to represent
  * that object when it does not exist.</p>
  * 
  * <p>This effect can only be run on targets that are either 

 * 
 * <p>Because the effect is bitmap-based, and the underlying
 * pixel-shader program expects both bitmaps to be the same size,
 * the effect will only work correctly when both bitmaps are
 * of the same size. This means that if the target object changes
 * size or changes orientation leading to a different size bounding
 * box, then the effect may not play correctly.</p>
 * 
 * <p>This effect and its subclasses differ from other effects in
 * Flex in that they are intended to work on their own, and may
 * not have the intended result when run in parallel with other effects.
 * This constraint comes from the fact that both of the before and after
 * bitmaps are captured prior to the start of the effect. So if something
 * happens to the target object after these bitmaps are calculated,
 * such as another effect changing the target's properties, then those
 * changes will not be accounted for in the pre-calculated bitmap and
 * the results may not be as expected. To ensure correct playing of
 * these bitmap-based effects, they should be played alone on
 * their target objects.</p>
 *  

    
    /**
     * A map of parameter name/value pairs passed to the pixel-shader program 
     * before playing. For example,
     * to set a parameter named <code>direction</code> in a
     * shader with a Pixel Bender pbj file in Wipe.pbj, the calling 
     * code could do the following:
