R/display-xy.r

In nspyrison/tourr: Implement Tour Methods in R Code

#' Display tour path with a scatterplot
#'
#' Animate a 2D tour path with a scatterplot.
#'
#' @param axes position of the axes: center, bottomleft or off
#' @param center if TRUE, centers projected data to (0,0).  This pins the
#'  center of data cloud and make it easier to focus on the changing shape
#'  rather than position.
#' @param half_range half range to use when calculating limits of projected.
#'   If not set, defaults to maximum distance from origin to each row of data.
#' @param edges A two column integer matrix giving indices of ends of lines.
#' @param col color to be plotted.  Defaults to "black"
#' @param pch size of the point to be plotted.  Defaults to 20.
#' @param origin_line row number(s) of data points to draw to the origin. Adopts
#'   the color of the point. If used \code{axes = "bottomleft"} is suggested.
#' @param ...  other arguments passed on to \code{\link{animate}} and
#'   \code{\link{display_xy}}
#' @export
#' @examples
#' animate_xy(flea[, 1:6])
#' animate(flea[, 1:6], tour_path=grand_tour(), display=display_xy())
#' animate(flea[, 1:6], tour_path=grand_tour(),
#'   display=display_xy(axes = "bottomleft"))
#' animate(flea[, 1:6], tour_path=grand_tour(),
#'   display=display_xy(half_range = 0.5))
#' animate_xy(flea[, 1:6], tour_path=little_tour())
#' animate_xy(flea[, 1:3], tour_path=guided_tour(holes), sphere = TRUE)
#' animate_xy(flea[, 1:6], center = FALSE)
#'
#' # The default axes are centered, like a biplot, but there are other options
#' animate_xy(flea[, 1:6], axes = "bottomleft")
#' animate_xy(flea[, 1:6], axes = "off")
#' animate_xy(flea[, 1:6], dependence_tour(c(1, 2, 1, 2, 1, 2)),
#'   axes = "bottomleft")
#' require(colorspace)
#' pal <- rainbow_hcl(length(levels(flea$species)))
#' col <- pal[as.numeric(flea$species)]
#' animate_xy(flea[,-7], col=col)
#'
#' # You can also draw lines
#' edges <- matrix(c(1:5, 2:6), ncol = 2)
#' animate(flea[, 1:6], grand_tour(),
#'   display_xy(axes = "bottomleft", edges = edges))
#'
#' # Adding lines to the origin
#' animate_xy(flea[,-7], col=col, axes = "bottomleft",
#'   origin_line = c(5, 30, 60))
display_xy <- function(center = TRUE, axes = "center", half_range = NULL,
                       col = "black", pch  = 20, edges = NULL,
                       origin_line = NULL, ...) {

  labels <- NULL
  init <- function(data) {
    half_range <<- compute_half_range(half_range, data, center)
    labels <<- abbreviate(colnames(data), 3)
  }

  if (!is.null(edges)) {
    if (!is.matrix(edges) && ncol(edges) == 2) {
      stop("Edges matrix needs two columns, from and to, only.")
    }
  }

  render_frame <- function() {
    par(pty = "s", mar = rep(0.1, 4))
    blank_plot(xlim = c(-1, 1), ylim = c(-1, 1))
  }
  render_transition <- function() {
    rect(-1, -1, 1, 1, col="#FFFFFFE6", border=NA)
  }
  render_data <- function(data, proj, geodesic) {
    draw_tour_axes(proj, labels, limits = 1, axes)

    # Render projected points
    x <- data %*% proj
    if (center) x <- center(x)
    x <- x / half_range
    points(x, col = col, pch = pch)

    if (!is.null(origin_line)) {
      if (length(col) > 1) lcol = col[origin_line]
      else lcol = col
      segments(0, 0, x[origin_line, 1], x[origin_line, 2],
               col = lcol)
    }

    if (!is.null(edges)) {
      segments(x[edges[,1], 1], x[edges[,1], 2],
               x[edges[,2], 1], x[edges[,2], 2])
    }
  }

  list(
    init = init,
    render_frame = render_frame,
    render_transition = render_transition,
    render_data = render_data,
    render_target = nul
  )
}

#' @rdname display_xy
#' @inheritParams animate
#' @export
animate_xy <- function(data, tour_path = grand_tour(), ...) {
  animate(data, tour_path, display_xy(...))
}

#' Draw tour axes with base graphics
#' @keywords internal
draw_tour_axes <- function(proj, labels, limits, position) {
  position <- match.arg(position, c("center", "bottomleft", "off"))
  if (position == "off") return()

  if (position == "center") {
    axis_scale <- 2 * limits / 3
    axis_pos <- 0
  } else if (position == "bottomleft") {
    axis_scale <- limits / 6
    axis_pos <- -2/3 * limits
  }

  adj <- function(x) axis_pos + x * axis_scale

  segments(adj(0), adj(0), adj(proj[, 1]), adj(proj[, 2]), col="grey50")
  theta <- seq(0, 2 * pi, length = 50)
  lines(adj(cos(theta)), adj(sin(theta)), col = "grey50")
  text(adj(proj[, 1]), adj(proj[, 2]), label = labels, col = "grey50")
}