[R-SIG-Mac]plot hidden grid lines 2

[Peter Paul Sint]

Dear Stefano,

Actually panel.first works somehow but not as I expected

jjbp<- barplot(1:5, panel.first=lines(c(0,5),c(1,2),lty="dashed"))
> jjbp    # position of bar mids
     [,1]
[1,]  0.7
[2,]  1.9
[3,]  3.1
[4,]  4.3
[5,]  5.5
> 
starts a line at c(0,5) but goes upward
(I understand it should advance from (0,1) to (5,2) 
 but it also does not work for (0,5)-(1,2)   ) 
somehow the axes/units seem to be mixed up.

After playing around I realize:
axes are probably scaled such that the xlim=ylim=c(0,1)
with this 
jjbp<- barplot(1:5, panel.first=abline(h=2/5,lty="dashed"))
works.

Is this what is intended? does R work this way on other platforms?
I assumed the axes of the barplot should be used.

abline uses the yaxis as main abscissa 
jjbp<- barplot(seq(0,1,0.2), panel.first=abline(0.5,-1)) 


Peter
-- 
Peter Sint
sint@oeaw.ac.at