Look at ?grconvertY, you can use this to convert from 'ndc' (normalized device coordinates) where 0 is the bottom of the device (window/page/...) to user coordinates that can be used in legend or other functions.
Hope this helps, -- Gregory (Greg) L. Snow Ph.D. Statistical Data Center Intermountain Healthcare [EMAIL PROTECTED] (801) 408-8111 > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Anne-Marie Ternes > Sent: Wednesday, July 02, 2008 3:42 AM > To: r-help@r-project.org > Subject: [R] position legend below x-axis title > > Dear helpers, > > I'm using a R script on several different datasets, which > makes that axis scales may vary quite a lot from dataset to > dataset. So what I'm looking for now, is how to automagically > find out how to position the legend (horizontal) in the space > below the x-axis title, and how to make sure that the legend > is within the limits of the lower inner or outer margin? > > I'm aware of plot, device and figure regions, and of the > "din, fin, pin, usr, mai, mar, omi, oma and xpd" parameters, > of inner and outer margins. > > I cannot simply position my legend on "minus something", as > that depends on "usr" coordinates, and those depend on the > scale of the y-axis. > > I tried finding the ideal spot by taking the figure height > and subtracting the upper margin, the height of the plot > region, and half of the lower margin. This is quite tedious > and doesn't help me, as I get a spot in inches, which doesn't > to correspond to the "usr" > coordinates. > > I also tried to convert between inches and "usr" coordinates > using "xy.coords", but the result did not correspond to the > position returned by "locator". > > I'm also aware of "mtext" and its fabulous arguments "side" > and "line", but there I loose the functionality of displaying > the legend symbols. > > Finally, I found a hint about using "layout", but there I > admit I would need more than a hint - a small tutorial or > graphical example with code would be very helpful. > > So, the question is, if there is per chance a way to pass > "side" and "line" arguments to "legend", and if not, what is > the best way to do what I try to do? BTW, the plot types > involved are mostly line plots and barplots. > > Thanks a lot for your help, > > Anne-Marie > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
