[magick-users] Magick++: Creating clipping mask

[Elie Zedeck RANDRIAMIANDRIRAY]

> I just found out that this technique (ChangeMask in the Usage pages) is
> not working on all kinds of image. I get a clipping mask that is not
> covering all the changes in my image.
>
> What could be the cause of that?
>   
I can't find the solution to this thing, so, I decide to do a low-level 
pixel comparison. What should I do to make navigating and comparing each 
pixel faster, because right now, it's slow.

Thanks.