R/plotly_packed_bar.R

In AdamSpannbauer/rPackedBar: Packed Bar Charts with 'plotly'

#' Create a 'plotly' packed bar chart

#' @description Packed bar charts are a variation of treemaps for visualizing skewed data.  The concept was introduced by XanGregg at JMP (\url{https://community.jmp.com/t5/JMP-Blog/Introducing-packed-bars-a-new-chart-form/ba-p/39972}).
#' @param input_data data.frame with data to plot, should have a column of labels for bars and column of numbers relating to bar length
#' @param label_column either the column number or quoted name in \code{input_data} to be used as labels (will be used by \code{[[} to subset)
#' @param value_column either the column number or quoted name in \code{input_data} to be used as numbers for bar lengths (will be used by \code{[[} to subset).  See details.
#' @param number_rows The number of rows to occur in barchart (i.e. the number of colored bars).  The default of 'guess' will attempt to find the 'elbow' in the numeric data with a min value of 3 and a max of 25.
#' @param plot_title main title for plot
#' @param xaxis_label label to put on xaxis
#' @param hover_label text to appear by number in hover information (typically same as xaxis label)
#' @param min_label_width min relative length of bar to receive a static label (too small and text will overflow sides of bar)
#' @param color_bar_color color of main bars in chart (can be name or hex) remaining bars will be variations of gray
#' @param label_color color of text labels that appear over colored bars
#' @return 'plotly' object of the packed bar chart
#' @importFrom plotly "%>%"
#' @details The packed barchart currently only works for uniformly positive or uniformly negative data; negative values will be removed before plotting when mixed data is provided.
#' @examples
#' \dontrun{
#' data(GNI2014, package = 'treemap')
#'
#' data.table::setDT(GNI2014)
#' my_input_data = GNI2014[,sum(population), by=country]
#'
#' plotly_packed_bar(my_input_data,
#'                   label_column    = "country",
#'                   value_column    = "V1",
#'                   plot_title      = "Population 2014",
#'                   xaxis_label     = "Population",
#'                   hover_label     = "Population",
#'                   min_label_width = .025,
#'                   color_bar_color = "orange")
#' }

#' @export
plotly_packed_bar = function(input_data, label_column, value_column,
                             number_rows="guess",
                             plot_title="",
                             xaxis_label="",
                             hover_label="",
                             min_label_width=.03,
                             color_bar_color="steelblue",
                             label_color = "black") {

  my_data_sum = data.table::copy(input_data)

  if (any(my_data_sum[[value_column]] > 0) & any(my_data_sum[[value_column]] < 0)) {
    warning("There were positve and negative values found in your `value_column`;
            plotly_packed_bar currently only supports uniformly positive or uniformly negative data.
            The negative values will be removed before plotting when mixed data is provided.")
    my_data_sum = my_data_sum[my_data_sum[[value_column]] > 0, ]
  }

  if (number_rows == "guess") {
    number_rows = guess_bar_count(my_data_sum[[value_column]], min_bar = 3, max_bar = 15)
  } else {
    if (is.numeric(number_rows)) {
      number_rows = as.integer(number_rows)[1]
    } else {
      stop("number_rows must be numeric or 'guess'")
    }
  }

  my_data_sum$max_rel_val = my_data_sum[[value_column]] / sum(my_data_sum[[value_column]])

  color_data = gen_color_bars(my_data_sum, number_rows, color_bar_color, label_column, min_label_width, label_color)
  gray_data  = gen_gray_bars(my_data_sum, number_rows, color_data$raw_data, label_column, min_label_width)

  #set canvas shape based on xvalues. make y points 0-1
  canvas_df = data.frame(x = 0:max(gray_data$row_sums), y = 0:1)

  x_labs = gen_xaxis_labels(gray_data$row_sums, sum(my_data_sum[[value_column]]))

  p = gen_plotly_packed_bar(my_data_sum, value_column,
                            color_bar_color, hover_label,
                            canvas_df,
                            plot_title, xaxis_label,
                            gray_data$hover_point_dt, color_data$hover_point_dt,
                            gray_data$bar_list, color_data$bar_list,
                            gray_data$ann_list, color_data$ann_list,
                            x_labs$tick_breaks, x_labs$tick_text)

  p = plotly::layout(p, margin = list(l = 0, r = 0))

  return(p)
}