function CalculateMouseDirection(const aStartPos, aCurrentPos : TPoint) : Integer;
{
 North      ->   0
 North-East ->  45
 East       ->  90
 South      -> 180
 West       -> 270
 NorthWest  -> 315
 etc.
}
var xDelta,yDelta : Integer;
               ex : Extended;
begin
  xDelta := aCurrentPos.X-aStartPos.X;
  yDelta := aStartPos.Y-aCurrentPos.Y;
  ex :=  (ArcTan2(xDelta, yDelta)*180) / PI;
  if ex<0 then ex := ex+360;
  Result := Round(ex);
end;