R/circleFun.R

In ThinkR-open/rusk: Beautiful Graphical Representation of Multiplication Tables on a Modular Circle

# https://stackoverflow.com/questions/6862742/draw-a-circle-with-ggplot2
circleFun <- function(center = c(0,0),r = 1, npoints = 100){
  tt <- seq(0,2*pi,length.out = npoints)
  xx <- center[1] + r * cos(tt)
  yy <- center[2] + r * sin(tt)
  data.frame(x = xx, y = yy)
}