🚀 go-pugleaf

Hi all,

I want to allow the user of my application to split the client window by
dragging a bar.  Ideally, I'd like this to work like Excel, where you
grab a little black spot in the scroll bar, and a line tracks the mouse
until the user lets go.  The line that tracks the mouse looks the same
as the border that tracks the mouse when you grab a window edge.

How do you draw (and undraw) this line?  It's not a line drawn in
inverse color.  There's some mask that seems to be drawn always in grey
(I can't tell for sure on my monitor), with the bits in between drawn in
inverse.  If it were just inverse, then the line wouldn't show up
patterned on a plain black or white background, right?

Anybody done this?  Thanks a lot!

-Jonathan Miller
jem@andrew.cmu.edu