R/draw_partylabels.R

In ggparliament: Parliament Plots

#' Draw labels for political parties and seats per party
#' @param party_names A column containing party names.
#' @param party_seats A column containing party seats.
#' @param party_colours A column containing party colours.
#' @param names  If TRUE, finds party names from data. Defaults to TRUE.
#' @param seats If TRUE, finds party seats from data. Defaults to TRUE.
#' @param type Define type. Currently only supports semicircle and horseshoe style parliaments.
#' @examples
#' data <- election_data[
#'   election_data$country == "USA" &
#'   election_data$house == "Representatives" &
#'   election_data$year == "2016",
#' ]
#' usa_data <- parliament_data(
#'   election_data = data,
#'   type = "semicircle",
#'   party_seats = data$seats,
#'   parl_rows = 8
#' )
#' ggplot2::ggplot(usa_data, ggplot2::aes(x, y, colour = party_long)) +
#'   geom_parliament_seats() +
#'   draw_partylabels(
#'     type = "semicircle",
#'     party_names = party_long,
#'     party_seats = seats,
#'     party_colours = colour
#'   ) +
#'   ggplot2::scale_colour_manual(
#'     values = usa_data$colour,
#'     limits = usa_data$party_long)  +
#'   theme_ggparliament()
#' @author Zoe Meers
#' @export
#' @importFrom ggplot2 ggplot_add


draw_partylabels <- function(type = c("semicircle", "horseshoe"),
                             names = TRUE,
                             seats = TRUE,
                             party_names = party_names,
                             party_colours = party_colours,
                             party_seats = party_seats) {
  structure(
    list(
      type = type,
      names = names,
      seats = seats,
      party_names = rlang::enquo(party_names),
      party_seats = rlang::enquo(party_seats),
      party_colours = rlang::enquo(party_colours)
    ),
    class = "partyLabels"
  )
}

#' @export
ggplot_add.partyLabels <- function(object, plot, object_name) {
  x <- y <- filter <- group_by <- summarise <- NULL

  #calculate the positions of the labels
  filt_data <- dplyr::filter(plot$data, row == max(row))
  group_data <- dplyr::group_by(filt_data, pn = !!object$party_names, ps = !!object$party_seats, pc = !!object$party_colours)
  new_dat <- dplyr::summarise(group_data, mean_x = mean(x), mean_y = mean(y))

  pos_movement_horseshoe <- c(new_dat$mean_x + 2)
  pos_movement_semicircle <- c(new_dat$mean_x + 0.8)
  neg_movement_horseshoe <- c(new_dat$mean_x - 2)
  neg_movement_semicircle <- c(new_dat$mean_x - 0.8)


  if (object$type == "horseshoe") {
    if (!(object$names) & !(object$seats)) {
      plot
    } else if (!(object$names) & object$seats) {
      plot + ggplot2::annotate("text",
        x = ifelse(new_dat$mean_x > 0,
          pos_movement_horseshoe,
          neg_movement_horseshoe
        ),
        y = new_dat$mean_y,
        label = new_dat$ps,
        colour = new_dat$pc,
        vjust = "outward"
      )
    } else if (object$names & !(object$seats)) {
      plot +
        ggplot2::annotate("text",
          x = ifelse(new_dat$mean_x > 0,
            pos_movement_horseshoe,
            neg_movement_horseshoe
          ),
          y = new_dat$mean_y,
          label = new_dat$pn,
          colour = new_dat$pc,
          vjust = "outward"
        )
    } else if (object$names & object$seats) {
      plot +
        ggplot2::annotate("text",
          x = ifelse(new_dat$mean_x > 0,
            pos_movement_horseshoe,
            neg_movement_horseshoe
          ),
          y = new_dat$mean_y,
          label = paste0(new_dat$pn, "\n(", new_dat$ps, ")"),
          colour = new_dat$pc,
          vjust = "outward"
        )
    }
  } else if (object$type == "semicircle") {
    if (!(object$names) & !(object$seats)) {
      plot
    } else if (!(object$names) & object$seats) {
      plot +
        ggplot2::annotate("text",
          x = ifelse(new_dat$mean_x > 0,
            pos_movement_semicircle,
            neg_movement_semicircle
          ),
          y = new_dat$mean_y,
          label = new_dat$ps,
          colour = new_dat$pc,
          vjust = "outward"
        )
    } else if (object$names & !(object$seats)) {
      plot +
        ggplot2::annotate("text",
          x = ifelse(new_dat$mean_x > 0,
            pos_movement_semicircle,
            neg_movement_semicircle
          ),
          y = new_dat$mean_y,
          label = new_dat$pn,
          colour = new_dat$pc,
          vjust = "outward"
        )
    }
    else if (object$names & object$seats) {
      plot +
        ggplot2::annotate("text",
          x = ifelse(new_dat$mean_x > 0,
            pos_movement_semicircle,
            neg_movement_semicircle
          ),
          y = new_dat$mean_y,
          label = paste0(new_dat$pn, "\n(", new_dat$ps, ")"),
          colour = new_dat$pc,
          vjust = "outward"
        )
    }
  }

  else {
    warning("Warning: parliament layout is not supported.")
  }
}