R/display-faces.r

In tourr: Implement tour methods in pure R code

#' Chernoff faces tour path animation.
#'
#' Animate a nD tour path with Chernoff's faces.  Can display up to 18
#' dimensions.
#'
#' This function requires the \code{TeachingDemos} package to draw the
#' Chernoff faces.  See \code{\link[TeachingDemos]{faces2}} for more details.
#'
#' @param ... other arguments passed on to \code{\link{animate}}
#' @seealso \code{\link{animate}} for options that apply to all animations
#' @keywords hplot
#' @aliases display_faces animate_faces
#' @examples
#' # The drawing code is fairly slow, so this animation works best with a 
#' # limited number of cases
#' animate_faces(flea[1:2, 1:6])
#' animate_faces(flea[1:4, 1:6])
#' 
#' animate_faces(flea[1:2, 1:6], grand_tour(5))
display_faces <- function(...) {

  render_data <- function(data, proj, geodesic) {
    x <- data %*% proj
    x <- (x + 2) / 4
    faces2(x, scale = "none")
  }
  
  list(
    init = nul,
    render_frame = nul,
    render_transition = nul,
    render_data = render_data,
    render_target = nul
  )
}


animate_faces <- function(data, tour_path = grand_tour(3), ...) {
  require("TeachingDemos")
  animate(data, tour_path, display = display_faces(...), ...)
}