Ahoy thar,
This is the one thing about bitmaps and bitmapData manipulation I really hate, trying to change something in one specific area never works out the way I thought it would 
My Problem is that I have a wide bitmapdata effect going horizontally across the page, for testing I just left the bitmapData be the height and width of the stage but I quickly discovered that this became unacceptable when I increased the size of the stage because the .applyFilter() method needs to compute the rest of the area too even though nothing is happening there. So then whipped up a quick function to find the bounding area of the visible effect, to keep it small (thankfully it will always be a rectangle) and I thought I might be able to shove that rectangle in one of the three different fields where it sounds like it might work… but nothing 
Every time the effect seemed to end up in some weird position or just have absolutely no effect :puzzled:
(Iv tried it in the .applyFilter field, the .draw field and just setting the bitmap x/y to the bounding box x/y with the bitmapData width/height to the bounding box width/height, as well as some time throwing random formulas here and there trying to position it)
My question is, what is the easiest way to use .applyFilter on a known bounding rectangle?
P.S The effect is some moving waves drawn on a sprite canvas using .graphics then drawn to the bitmapData using .draw(), so anyway to use these to restrict the bitmapData area is oky doky too 
Thanks in advance
