R/get.ellipse.R

In msxakk89/dat: Data Analyst Toolkit (dat): a library of tools for data analysts and scientists

#' Calculate points on an ellipse described by the fit argument as returned by fit.ellipse.
#' 
#' Function to calculate the points of the ellipse.
#' 
#' @param fit A list object output from fil.ellipse() function
#' @param n Number of points to render. Defults to n=360.
#' @export

get.ellipse <- function( fit, n=360 ) 
{
  tt <- seq(0, 2*pi, length=n) 
  sa <- sin(fit$angle) 
  ca <- cos(fit$angle) 
  ct <- cos(tt) 
  st <- sin(tt) 
  
  x <- fit$center[1] + fit$maj * ct * ca - fit$min * st * sa 
  y <- fit$center[2] + fit$maj * ct * sa + fit$min * st * ca 
  
  cbind(x=x, y=y) 
}