Continuous MouseDown Colorization of Graphic Grid?

[John Patten]

Hi All...

I've created a grid of graphic rectangles that I can colorize and make  
transparent (blend). I would like to be able to let the user drag the  
mouse while holding the mouse button down and colorize each rectangle  
they drag across.  On the flip side, if the rectangle is already  
colorized, I would like to it to turn it's blend level to 100 and set  
its color to empty. Again, if there were a series of rectangles in the  
grid that were colorized, dragging across them with the mouse down  
with de-colorize them.

I can't seem to get my head around the mousedown while dragging part?   
I've tried mouseEnter, but that gets messy when accidentally dragging  
over a rect in the grid you don't want colorized; I have tried  
MouseStillDown with no luck there either.

Anyone done anything similar with a transparent grid?

The grid would sit on top of an image, like for example a map, and the  
colorizing would enable the user to, essentially, focus in on a  
particular part of the image below.


Thank you!

John Patten