Just an observation. Sorry, I haven't got time at the moment to go
through the code and maybe I'm missing the point, but.
You use GetPixel to identify the colour of a prior arrow. This may
work, but isn't there a more precise way to keep record of arrow
position and colour?
GetPixel is not really future proof, unless you know for certain that
your layout will never change.<<<
Since I calculate anyway where to draw the arrow and how long it's has to be, I thought that I also can use it to check the colour, or?
It's works good if I print out the colour from the certain pixel. It's gives the expected colour but don't draw the arrow on the right place.
Regards
Stefanie