[R] lines at margin?

[Marc Schwartz (via MN)]

On Mon, 2006-10-09 at 10:56 -0400, Mike Wolfgang wrote:
> Hi list,
> 
> I want to add some lines at margin area of one figure. mtext could add text
> to these margins, can I add lines with different lty parameters? Thanks,
> 
> mike

You can do it, but it will take some fiddling to get the coordinates
right:

 # Do a generic plot
 plot(1:10)

 # Get the current plot region axis ranges
 # x1, x2, y1, y2
 par("usr")
 [1]  0.64 10.36  0.64 10.36

 # Draw a vertical line in the right hand margin
 # Set 'xpd = TRUE' so that plotting is not
 # clipped at the plot region boundary
 segments(10.75, 4, 10.75, 6, xpd = TRUE)

See ?par for more information.

HTH,

Marc Schwartz