how to get actor pixel alpha value

Could anyone explain ho to get an actors alpha value?
I realise that I probably need to use a code block, and a search of the forum brings up some code that may work - but i'm not sure how to put it all together.

This would make for a great extension!!

Any help greatly appreciated.

I don't know if this would work for you but there is a block in Images -> Change Images;

[get pixel at (x:_, Y:_) for {image from Actor} ]

Fantastic thanks! that's just what I needed. I'd seen that block previously, but just assumed it would return an rgb value.

Do you know what format the returned value is in? its 8 digits long so I assumed it was RGBA or ARGB hex at first, but it's not.

That block doesn't include alpha.  You'd have to use code to get it.  See this thread (I don't think a list is needed anymore): http://community.stencyl.com/index.php/topic,19596.0.html