Consistently shading row in addtable2plot - plotrix
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I'm regularly generating histograms from simulated data, and find it quite helpful to attach an associated decile table for the data. I've been doing this with the addtable2plot function from plotrix. I also find it useful to highlight the row in the table which contains the 50% value - here is an example:


    library(plotrix)

    # Generate data

    mu <- -1.771957
    sd <- 0.4716474

    foo <- rlnorm(100000, mu, sd)

    # Generate decile table
    xmax <- .75

    max <- format(xmax, digits=2, nsmall=2)

    dc <- quantile(foo, probs=seq(0, 1, 0.1))
    dps <- c("100%", "90%", "80%", "70%", "60%", "50%", "40%", "30%", "20%", "10%", "0%")
    dc <- format(round(dc, digits=2), nsmall=2)

    decile <- as.data.frame(dps)
    deciles <- as.data.frame(cbind(dps,dc), row.names=FALSE)
    colnames(deciles) <- c("Probability", "Rate")
    deciles$"Rate" <- as.character(deciles$"Rate")
    deciles[1,2] <- "0.00"
    deciles[11,2] <- paste(">", max, sep="")

    # create a plot
    hist(foo, freq=F, xlim=c(0,xmax), breaks=50, col="blue")
    top <- max(axis(2))
    rect(xleft=(.69*xmax), xright=(1.04*xmax), ybottom=(.615*top), ytop=(.665*top), col="gray91", border=NA)
    addtable2plot(x=(1.04*xmax), y=(top), xjust=1, yjust=0, table=deciles, cex=0.82,
              title="Title", hlines=TRUE, vlines=TRUE, bty="o", lwd=1.5, bg="transparent")

As you can see, I've been shading simply by adding a colored rectangle underneath the table plot. This takes a lot of tweaking on the xleft, ybottom, and ytop parameters for each histogram. 

Is there any way to consistently do this highlighting without all the hassle?
Thanks, 