On Wed, 2007-01-10 at 21:18 -0600, David Forrest wrote: > Hi, > > I'd like to produce a marginless or zero margin plot so that the pixel > coordinates represent the mathematics. > > xy<-data.frame(x=c(0,1,1,0,0),y=c(0,1,0,0,1)) > png('junk.png',width=300,height=300) > par(mar=c(0,0,0,0)) > plot(xy$x,xy$y,xlim=c(0,1),ylim=c(,1)) > dev.off() > > The resultant file has about a 10 pixel margin around these lines, and I'm > not sure what parameter or function is controlling this offset. Any > hints? > > Thanks for your time, > Dave
By default, the axis ranges are extended by +/- 4%. You can change this by using: plot(xy$x, xy$y, xlim = c(0, 1), ylim = c(0, 1), xaxs = "i", yaxs = "i") where 'xaxs' and 'yaxs' set the axis ranges to the actual data ranges. See ?par for more information. HTH, Marc Schwartz ______________________________________________ R-help@stat.math.ethz.ch 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.