[Seqinr-commits] r1634 - pkg/man

[noreply at r-forge.r-project.org]

Author: lobry
Date: 2009-09-03 10:49:55 +0200 (Thu, 03 Sep 2009)
New Revision: 1634

Added:
   pkg/man/col2alpha.Rd
Log:
 

Added: pkg/man/col2alpha.Rd
===================================================================
--- pkg/man/col2alpha.Rd	                        (rev 0)
+++ pkg/man/col2alpha.Rd	2009-09-03 08:49:55 UTC (rev 1634)
@@ -0,0 +1,31 @@
+\name{col2alpha}
+\Rdversion{1.1}
+\alias{col2alpha}
+\title{To use a standard color with an alpha transparency chanel}
+\description{
+Takes as input a standard R color and an alpha value to return
+its rgb coding.
+}
+\usage{
+col2alpha(color, alpha = 0.5)
+}
+\arguments{
+  \item{color}{A standard R color as in \code{\link{colors}}.}
+  \item{alpha}{An alpha transparency value in the interval [0,1].}
+}
+\value{same as in \code{\link{rgb}}.}
+\author{J.R. Lobry}
+\seealso{\code{\link{colors}}, \code{\link{col2rgb}}, \code{\link{rgb}}.}
+\examples{
+par(mar = c(0, 0, 2, 2)+0.1, oma = c(0, 0, 2, 0), mfrow = c(3,2))
+for(testcol in c("blue", "red", "green", "yellow", "purple", "darkgreen")){
+  plot(0,0, type="n", xlim=0:1, ylim = 0:1, axes = FALSE, xlab = "", ylab = "", main = testcol)
+  n <- 11
+  for(i in seq(0, 1, length = n)){
+    col <- col2alpha(testcol, i)
+    rect(i, 0, i + 1/n, 1, col = col, border = "black", xpd = NA)
+    text(i+0.5/n, 0.5, round(i,2), xpd = NA)
+  }
+}
+mtext("Effect of alpha on some colors", side = 3, outer = TRUE)
+}