[R] barplot and ylim - display problems

[Marc Schwartz]

On Fri, 2005-02-18 at 14:47 +0000, Dan Bolser wrote:
> 
> The following single line of code shows what I am trying to do, and the
> problem I am having...
> 
> barplot(c(101,102,103),ylim=c(100,103))
> 
> The 'xaxis' is missing, and the grey bars 'fall off' the plot area. This
> is generally ugly, and I would like to trim the bars (ideally they would
> have a ragged appearance to show that I am 'zooming in').
> 
> I can see why what I am trying to do is conceptually a bit tricky, as the
> yaxis needs to be closly inspected to see the data in its propper context.
> This is simply fixed by showing...
> 
> barplot(c(101,102,103))
> 
> However, I want to first show the data in its propper context, then 'zoom
> in' to highlight the difference between the bars. 
> 
> I tried covering up the bottom of the chart with a rect() command, but it
> wont draw ouside the area highlighted with the box command, for example 
> 
> 
> barplot(c(101,102,103),ylim=c(100,103))
> box()
> rect(0.7,0,1.9,102.5,col="white")
> 
> So I can't work out how to stop bars falling off the end of the plot, so
> my labels are being written on the bars.
> 
> How can I fix this?

Dan,

Try this:

barplot(c(101,102,103),ylim=c(100,103), xpd = FALSE)

Note that the setting of par("xpd") clips the bars outside the plot
region.

See ?par for more information.

HTH,

Marc Schwartz