> thanks
> that was very helpful. 
> i have been reading  and trying to modify the code around to suit, but
haven't been able to:

> first, maximize the chart with the window being maximized, the way it
is it stays the same size after maximizing the window.
 
The function tkrplot has optional arguments hscale and vscale that can
be used to adjust the initial size of the graph, but currently tkrplot
does not do dynamic resizing.  To make the plot 3 times as wide and 2
times as tall just change the tkrplot call to:
 
img <- tkrplot(tt,f1,hscale=3,vscale=2)
 
 
> second, plotting another sequence which share the same index with the
first sequence but with different values, its scale  
>  I wish to place on the right side of the chart.

 Add your code for the second series to the f1 function.  Something
like:
 
 f1 <- function(){
lleft <- as.numeric(tclvalue(left))
rright <- as.numeric(tclvalue(right))
x <- seq(lleft,rright,by=1)
plot(x,y[x], type='b',ylim=range(y,y2))
points(x,y2[x],type='b', col='green')
axis(4)
}
 
or
 
f1 <- function(){
lleft <- as.numeric(tclvalue(left))
rright <- as.numeric(tclvalue(right))
x <- seq(lleft,rright,by=1)
plot(x,y[x], type='b',ylim=range(y))
par(new=TRUE)
plot(x,y2[x], type='b', col='green', axes=F)
axis(4)
}

Hope this helps, 


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