Hello to all and excused for my bad English

With following macro I can easily draw a line

sub draw_line ()
Xp1 = 1
Yp1 = 60
Xp2 = 1900
Yp2 = 60
ActiveSheet.Shapes.AddLine (Xp1, Yp1, Xp2, Yp2). Name = "line1"
end sub

We suppose that with a successive macro I want to determine the used
parameters in order to trace the line1.
What's the method to determine the 4 used parameters in order to trace the
line through code VBA; that is Xp1 Yp1 Xp2 Yp2?

Thanks for the attention.
Diego.