{ Adds a line to the series which connects the points P1 and P2. The line
is drawn in the specified color. }
procedure TForm1.AddLine(ASeries: TFieldSeries; P1, P2: TDoublePoint; AColor: TColor);
var
center: TDoublePoint;
direction: TDoublePoint;
begin
center := (P1 + P2) * 0.5;
direction := P2 - P1;
ASeries.AddVector(center.X, center.Y, direction.X, direction.Y, '', AColor);
end;