Dear Achim, As I mentioned in my response to Deepayan's suggestion, I didn't specify the original problem clearly: The object is to get contrasting colours, so that when one is plotted over the other, the two will be readily distinguishable. Your suggestions don't do this for neutral colours:
> x <- "#888888" > y_hcl <- as(hex2RGB(x), "polarLUV") > [EMAIL PROTECTED], "H"] <- [EMAIL PROTECTED], "H"] + 180 > hex(y_hcl) [1] "#888888" > y_hsv <- as(hex2RGB(x), "HSV") > [EMAIL PROTECTED], "H"] <- [EMAIL PROTECTED], "H"] + 180 > hex(y_hsv) [1] "#888888" Thank you for trying to help. John -------------------------------- John Fox, Professor Department of Sociology McMaster University Hamilton, Ontario Canada L8S 4M4 905-525-9140x23604 http://socserv.mcmaster.ca/jfox -------------------------------- > -----Original Message----- > From: Achim Zeileis [mailto:[EMAIL PROTECTED] > Sent: Monday, May 21, 2007 7:07 PM > To: John Fox > Cc: r-help@stat.math.ethz.ch > Subject: Re: [R] Selecting complementary colours > > On Mon, 21 May 2007, John Fox wrote: > > > Dear r-helpers, > > > > I wonder whether, given the "#rrggbb" representation of a colour, > > there is a simple way to select the complementary colour, > also expressed as a "#rrggbb" > > string. > > Is the complementary color uniquely defined? My understanding > is that you can take opposite colors on a color wheel, but > there are of course various color wheels available. With > "colorspace" you can experiment with this, > e.g.: > x <- "#81A9D0" > y_hcl <- as(hex2RGB(x), "polarLUV") > [EMAIL PROTECTED], "H"] <- [EMAIL PROTECTED], "H"] + 180 > y_hcl <- hex(y_hcl) > which is a bit more balanced than > y_hsv <- as(hex2RGB(x), "HSV") > [EMAIL PROTECTED], "H"] <- [EMAIL PROTECTED], "H"] + 180 > y_hsv <- hex(y_hsv) > > hth, > Z > > > ______________________________________________ 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.
