R: Create Watermark for SAS ODS Reports

Now to see if we can add some watermarks in SAS ODS - I've seen pages on how to create watermarked reports using background images. The first part is creating the background image: we can steal some code from the earlier post on watermarks in R, and adapt it to create PNG backdrops for our reports.

So let's create a function which does this for us: we just tell it what we want the watermark to say, and pass it a couple parameters: the color, size, angle, and font of the text.

# create a date-stamped folder for the results
run.date <- format(Sys.Date(), "%m-%d-%Y")
working.dir <- paste0("c:/Data/Didactic/Results/", run.date)
create.watermark <- function(wm = "", rep.wm = T, n.reps = 5,
    result.dir,    res.wm = 1200, cex.wm = 2, font.wm = 2,
    col.wm = rgb(1, 0, 0, .2), angle.wm = 45,
    page.width = 8.5, page.height = 11, page.unit = "in") {
    if (file.exists(working.dir)) {
        setwd(file.path(working.dir))
    } else {
        dir.create(working.dir, recursive = T, showWarnings = F)
        setwd(working.dir)
    }

    if (rep.wm == T) {
        x.loc <- seq(0, 1, length.out = n.reps)
        y.loc <- seq(1, 0, length.out = n.reps)
    } else {
        x.loc <- .5; y.loc <- .5;
        n.reps <- 1
    }

  
    setwd(result.dir)

    # create a date-stamped .png file
    png(paste0("Watermark Background - ", wm, " ", run.date,
    " ", res.wm, " dpi.png"),
        width = page.width, height = page.height, res = res.wm,
        units = page.unit)

        par(mar = c(0, 0, 0, 0))
        plot.new()
        text(grconvertX(x.loc, from = "npc"),
            grconvertY(y.loc, from = "npc"),
            labels = paste(rep(wm, n.reps), collapse = "   "),
            cex = cex.wm, font = font.wm,
            col = col.wm,
            srt = angle.wm)
    dev.off()
}


The program creates the image, and labels it appropriately with the watermark, run date, and resolution. In part 2, I'll see if I can make a nice looking report with the background image, maybe even using a report on simulated survival data.


Now, let's see if it works. First, let's create a repeated watermark across the page:

create.watermark(wm = "CONFIDENTIAL", result.dir = working.dir, res.wm = 300)


Next, just one single large watermark in the background:

create.watermark(wm = "FOR PEER REVIEW ONLY", rep.wm = F,
col.wm = rgb(0, 0, 1, .2), result.dir = working.dir, cex.wm = 5, res.wm = 300)

Suggestions for further improvements welcome!