Flowing triangles

I have admired the work of the artist Bridget Riley for a long time. She is now in her eighties, but as it seems still very creative and productive. Some of her recent work combines simple triangles in fascinating compositions. The longer I look at them, the more patterns I recognise.

Yet, the actual painting can be explained easily, in a sense of a specification document to reproduce the pattern precisely. However, seeing the real print, as I had the chance at the London Art Fair last week, and a reproduction on the screen is incommensurable.

Having said that, I could not resist programming a figure that resembles the artwork labelled Bagatelle 2. Well, at least I can say that I learned more about grid [1], grid.path [2] and gridSVG [3] in R.

R Code

	library(data.table)
	ya <- sqrt(3) * 0.5
	yp <- c(2, 2, 2 - ya)
	x_iter <-c(1:6, 0.5:7.5, 1:8, 0.5:7.5, 2:7)
	DT <- data.table(
	x = unlist(lapply(x_iter,
	function(t) c(1, 2, 1.5) + t)),
	y = c(rep(yp, 6) + 4, rep(yp, 8) + 4 - ya,
	rep(yp, 8) + 4 - 2*ya, rep(yp, 8) + 4 - 3*ya,
	rep(yp, 6) + 4 - 4*ya),
	id = rep(1:36, each=3)
	)
	n <- 49
	t <- seq(pi*7/3, pi*2, length=n)
	xin <- cos(t) - min(cos(t))
	yin <- sin(t) - max(sin(t))
	xout <- cos(t - pi) - min(cos(t - pi))
	yout <- sin(t - pi)
	DT <- rbindlist(
	list(
	DT,
	rbindlist(lapply(c(10, 11, 13, 15, 25:28, 30, 35), function(i){
	data.table(x=DT[id==i, x][3] - xin,
	y=DT[id==i, y][3] - yin, id=i)
	})),
	rbindlist(lapply(c(4, 6, 7, 17:19, 21, 31:33), function(i){
	data.table(x=DT[id==i, x][3] - rev(xout),
	y=rev(DT[id==i, y][3] - yout), id=i)
	}))
	)
	)
	xmax=max(DT[,x])
	ymax=max(DT[,y])
	library(grid)
	grid.newpage()
	pushViewport(
	viewport(name="vp1",
	layout=grid.layout(1,1,
	widths=9,
	heights=5,
	respect=TRUE)))
	pushViewport(
	viewport(name="vp2", layout.pos.row=1,
	layout.pos.col=1, xscale=range(DT[,x]),
	yscale=range(DT[,y]), clip=TRUE))
	grid.rect(gp=gpar(fill="white"))
	grid.path(DT[,x]/xmax-0.05, DT[,y]/ymax-0.1, id=DT[,id],
	gp=gpar(fill="black"))
	library(gridSVG)
	grid.export("Bagatelle_2.svg")
	browseURL("Bagatelle_2.svg")

view raw Bagatelle_2.R hosted with ❤ by GitHub

References

[1] P. Murrell. R Graphics, Second Edition. CRC Press. 2011
[2] P. Murrell. What's in a Name? . The R Journal, 4(2):5–12, dec 2012.
[3] P. Murrell and S. Potter. gridSVG: Export grid graphics as SVG. R package 1.5-0. 2015

Session Info

R version 3.2.3 (2015-12-10)
Platform: x86_64-apple-darwin13.4.0 (64-bit)
Running under: OS X 10.11.2 (El Capitan)

locale:
[1] en_GB.UTF-8/en_GB.UTF-8/en_GB.UTF-8/C/en_GB.UTF-8/en_GB.UTF-8

attached base packages:
[1] grid      stats     graphics  grDevices utils  datasets 
[7] methods   base     

other attached packages:
[1] gridSVG_1.5-0    data.table_1.9.6

loaded via a namespace (and not attached):
[1] tools_3.2.3   RJSONIO_1.3-0 chron_2.3-47  XML_3.98-1.3

Posted by Unknown

Tweet