# Masking question continued

**URL:** <https://forum.kirupa.com/t/masking-question-continued/246778>\
**Category:** Uncategorized\
**Created:** [December 14, 2007, 1:20pm UTC](https://forum.kirupa.com/t/masking-question-continued/246778 "2007-12-14T13:20:15Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![stumped](https://avatars.discourse-cdn.com/v4/letter/s/46a35a/32.png) [@stumped](https://forum.kirupa.com/u/stumped)\
**Post date:** [December 14, 2007, 1:20pm UTC](https://forum.kirupa.com/t/masking-question-continued/246778/1 "2007-12-14T13:20:15Z")

</div>

This is a different question than the one in the thread “masking question”. I am revealing an image that initially is entirely covered by a mask. The code is based on the tutorial: [http://www.actionscript.org/resources/articles/168/1/Dynamic-masking-using-the-drawing-API/Page1.html](http://www.actionscript.org/resources/articles/168/1/Dynamic-masking-using-the-drawing-API/Page1.html)  
I want the program to know what percentage of the mask has been removed. When 90% of the mask has been removed I want it to trigger an event. Is there a simple way to do this? Any suggestions will be greatly appreciated.

Thanks so much … Michael