"John Fox" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED]
> The object is to get contrasting colours, so that > when one is plotted over the other, the two will be readily > distinguishable. A simple approach to contrast is to compute a mean intensity by taking the mean of the three RGB components (should be 0..255) and then going with either "black" or "white" -- whichever one is "farthest" away. Look at the Color Chart with contrasting numbers http://research.stowers-institute.org/efg/R/Color/Chart/index.htm or http://research.stowers-institute.org/efg/R/Color/Chart/ColorChart.pdf efg Earl F. Glynn Stowers Institute for Medical Research ______________________________________________ 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.
