Help with mouse dragging in grid

[jacobhot999]

http://pastebin.com/qw00TCd6
(code if needed)

I've created a grid, and a double array of my class gridBalls.
gridBalls has a int type, and you pass to it a number to determine
what to draw in the grid, like 0 blank, 1 ball etc.
What would the code look like in my mousedragged if I wanted to lets say
click on the slot [0] [0] on my grid (pretend its a ball), drag my mouse
to the right and draw a horizontal line (type 3 in this example), or if I
dragged my mouse bottom and it drew a vertical line (type 2)

Thanks