Thanks for the inputs!
I have adjusted the function:
- it shows now a pie or lines and bars (default)
- it stops if there is no match for the searched color string
- it returns the list of the colors
Below you find the proposed new code.
Wolfram
#--- showcolors.R
showcolors <-
function(
col = "red" # pattern string for search in colors() or vector of colors
, index = NULL # numeric vector for subselection
, pie = FALSE # display as pie, otherwise as bars and lines
, lwd = 1 # line width for lines
, cex = 1.0
, main = NULL
, sub = NULL
, plot = TRUE
, ...
){
n.colors <- length( col )
if( n.colors > 1 ){
main <- deparse( substitute( col ) )
title <- qt.colors <- col
}else{
qx.colors <- grep( col, colors() )
if( length( qx.colors ) == 0 )
stop( paste(sep=""
, "There is no color name which matches ``", col, "''.\n" ) )
if( ! is.null( index ) ) qx.colors = qx.colors[ index ]
else index = seq( along=qx.colors )
if( is.null( main ) ) main <- paste( sep="", col
, ' [', min(index), ':', max(index), ']' )
qt.colors <- colors()[ qx.colors ]
n.colors <- length( qt.colors )
}
if( plot ){
if( pie ){
pie( x = rep( 1, n.colors ), col = qt.colors, labels = qt.colors
, main = main, sub = sub, cex = cex, ... )
}else{
plot( type='n', x = c( -2, 2 ), y = c( 1, n.colors )
, main = main, sub = sub, axes = FALSE, xlab = '', ylab = '' )
text( x = rep( 0, n.colors ), y = 1 : n.colors
, labels= qt.colors, cex = cex )
segments(
x0 = rep( -1.5, n.colors ), y0 = 1 : n.colors
, x1 = rep( -0.5, n.colors ), y1 = 1 : n.colors
, col = qt.colors, lwd = lwd, ... )
rect(
xleft = rep( 0.5, n.colors )
, ybottom = 1 : n.colors - 0.4
, xright = rep( 1.5, n.colors )
, ytop = 1 : n.colors + 0.4
, col = qt.colors, ... )
}
}
invisible( qt.colors )
}
#--- showcolors.Rd
\name{showcolors}
\title{Displaying Colors}
\alias{showcolors}
\synopsis{
showcolors(col="red", \dots)
}
\description{
\code{showcolors} displays selected colors
(by searching color names containing a text pattern
or given by a vector of colors)
as lines or bars or in a pie.
}
\usage{
showcolors(col="red", index=NULL, pie=FALSE, lwd=1, cex=1,
main=NULL, sub=NULL, plot=TRUE, \dots)
}
\arguments{
\item{col}{pattern string for search in \code{colors}.
Alternatively, a vector of colors.}
\item{index}{a numeric index for subselection
in the result of \code{col}.}
\item{pie}{logical. If \code{TRUE}, a colored pie is displayed.
Alternatively, colored lines and bars are displayed.}
\item{lwd}{line width for lines.}
\item{cex}{the character size to be used for the labels.}
\item{main}{an overall title for the plot.}
\item{sub}{a sub title for the plot.}
\item{plot}{logical. If \code{FALSE}, nothing is plotted.}
\item{\dots}{graphical parameters can be given as arguments
to \code{plot}.}
}
\details{
If \code{col} has length of 1 then all colors a displayed
with names containing the text string \code{col}.
The search is done by \code{grep}.
By default, a pie with the colors found is drawn,
labelled by the names of the colors.
}
\value{
A vector of the color names to show.
}
\seealso{
\code{\link{colors}},
\code{\link{palette}},
\code{\link{rainbow}},
\code{\link{grep}}.
}
\author{
Wolfram Fischer
}
\examples{
showcolors()
showcolors( palette() )
showcolors( rainbow(24) )
showcolors( "yellow" )
showcolors( "yellow", pie=TRUE )
showcolors( "blue", index=26:50 )
}
\keyword{color}
\keyword{dplot}
#---
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