From: Thomas Lumley <tlumley_at_uw.edu>

Date: Thu, 14 Apr 2011 08:07:04 +1200

Date: Thu, 14 Apr 2011 08:07:04 +1200

On Thu, Apr 14, 2011 at 5:30 AM, Michael Friendly <friendly_at_yorku.ca> wrote:

> I have a diagram to be included in latex, where all my figures are .eps

*> graphics (so pdflatex is not an
**> option)
*

You could use the pdf() device and then use pdf2ps to convert to PostScript.

>and I want to achieve something

*> like the following: three concentric filled circles varying in lightness or
**> saturation. It is easiest to do this using
**> transparency, but in my test using the postscript driver, the transparent
**> color fills do not appear. Is it
**> correct that postscript() does not support transparency?
**>
**> circle <-function (radius = 1, segments=61) {
**> angles <- (0:segments)*2*pi/segments
**> radius * cbind( cos(angles), sin(angles))
**> }
**>
**> plot(1:5, 1:5, type='n', xlim=c(-1,5), ylim=c(-1,5), xlab='', ylab='',
**> asp=1, xaxt="n", yaxt="n")
**>
**> #clrs <- trans.colors("lightblue", alpha=c(.2, .4, .6)) ## from heplots
*

There's now an adjustcolor() function in base R to do this.

*> package
**> clrs <- c("#ADD8E633", "#ADD8E666", "#ADD8E699")
**>
*

> c1 <- circle(3)

*> polygon( c1, col=clrs[1], border="lightblue")
**> polygon(.67*c1, col=clrs[2], border="lightblue")
**> polygon(.33*c1, col=clrs[3], border="lightblue")
**>
**> arrows(-1, 0, 5, 0, angle=10, length=.2, lwd=2, col="darkgray")
**> arrows( 0, -1, 0, 5, angle=10, length=.2, lwd=2, col="darkgray")
**>
**> One alternative that sort of works is to use the png() driver, and then
**> convert fig.png fig.eps
**> but I need very high resolution to make the real diagram legible.
**>
**> It might suffice to use hcl() colors to approximate what I've done with
**> transparency,
**> but I don't know how to start with a given color ("lightblue") and achieve
**> roughly
**> similar resuts.
*

It would be useful to have an alpha-blending function for this sort of purpose, but I don't think we have one.

-thomas

-- Thomas Lumley Professor of Biostatistics University of Auckland ______________________________________________ R-help_at_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.Received on Wed 13 Apr 2011 - 20:10:38 GMT

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