Weekend art in R (Part 3)

I have a few posts nearing completion, but meanwhile a weekend break for art. Big thanks to Simon Urbanek and Jeffrey Horner, creators of Cairo, a library for the programming language R. Have you noticed how R can’t anti-alias (fancy way for saying smooth out lines and curves when creating a bit-mapped image)? Cairo can.

Make sure to click the image above for the full version. Here’s my code:

# The Cairo library produces nice, smooth graphics
Cairo(1200, 1200, file="D:/Your/Path/Here/Dots.png", type="png", bg="#FF6A00")

# How big should the grid for placing dots be?
myWidth=40
myHeight=40

dotsPlaced = myWidth*myHeight

# Optional default colors and sizes for dots
myColors = rep(c("#0000F0","#00F000"),dotsPlaced)
myCex = rep(3.2,dotsPlaced)

for(i in 1:dotsPlaced) {
	# Change this to allow more of the default color dots to survive
	if(runif(1)<1) {
		myColors[i] = paste("#",paste(sample(c(3:9,"A","B","C","D","E","F"),6,replace=T),collapse=""),collapse="",sep="")
	}
	myCex[i] = runif(1,3,6)
}

# Keeping this is marginal
par(oma=c(0,0,0,0))
par(mar=c(0,0,0,0))

# Start off with a blank plot. The white dot helps with cropping later
plot(0,0,pch=".",xlim=c(0,40),ylim=c(0,40),col="white", xaxt = "n", yaxt = "n")

for(m in 1:myWidth) {
	for(n in 1:myHeight) {
		if(runif(1) < .93) {
			points(n,m,pch=20,col=myColors[((m*n)+n)],cex=myCex[((m*n)+n)])
		}
	}
}

dev.off() # Tell Cairo to burn the plot to disk

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This entry was posted on Saturday, August 21st, 2010 at 7:50 am and is filed under art, feature, r. You can follow any comments to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

4 comments

  1. Matt
    August 22, 2010 at 6:33 pm

    Is this a test for color blindness? 😉

  2. Lee
    August 23, 2010 at 10:40 am

    I always wondered why exported graphics look kinda ugly. Very cool package, thanks for pointing it out!

  3. Ruben Garcia
    August 26, 2010 at 5:36 am

    Hi there,
    I’m trying to replicate your results using R 2.10.1 on Windows XP but I keep on getting an error message regarding the following snippet:

    for(i in 1:dotsPlaced) {
    # Change this to allow more of the default color dots to survive
    if(runif(1)<1) {
    myColors[i] = paste(“#”,paste(sample(c(3:9,”A”,”B”,”C”,”D”,”E”,”F”),6,replace=T),collapse=””),collapse=””,sep=””)
    }
    myCex[i] = runif(1,3,6)
    }

    R complains about an unexpected ‘;’ after lt.

    I’m just trying to copy and paste your code after having loaded the cairo package.

    Any suggestions about how to make your code to work would be greatly appreciated.
    Many thanks in advance,
    Ruben

  4. Matt Asher
    August 28, 2010 at 7:51 am

    Hi Ruben,

    I fixed the code. For some reason 2 of the < signs were HTMLized into & l t ; in the code. I changed those. Let me know if you still have problems running it. Cheers, Matt