It started with the #30DayChartChallenge…

Goldilocks data

goldilocks <- tibble::tibble(
  from = c(
    "Goldilocks", "Porridge", "Porridge", "Porridge",
    "Just right", "Chairs", "Chairs", "Chairs",
    "Just right2", "Beds", "Beds", "Beds",
    "Just right3"
  ),
  to = c(
    "Porridge", "Too cold", "Too hot", "Just right",
    "Chairs", "Still too big", "Too big", "Just right2",
    "Beds", "Too soft", "Too hard", "Just right3",
    "Bears!"
  )
)

Other packages and tools for flowcharts

It’s just rectangles, text, and lines…

The Goldilocks Decision Tree

…it also inspired the hex sticker!

Building {ggflowchart}

Aims

• Simple wrapper function to create a flowchart from a data.frame

• Users don’t have to define node position

• Works with existing {ggplot2} styling options

A simple example

library(ggflowchart)
flow_data <- tibble::tribble(
  ~from, ~to,
  "A", "B",
  "A", "C",
  "A", "D",
  "B", "E",
  "C", "F",
  "F", "G"
)
ggflowchart(flow_data)

Layouts with {igraph}

get_layout <- function(data, layout = "tree", node_data = NULL) {
  
  # some argument tests are in here ...

  if (layout == "tree") {
    data <- dplyr::select(data, c(.data$from, .data$to))
    g <- igraph::graph_from_data_frame(data, directed = TRUE)
    coords <- igraph::layout_as_tree(g)
    colnames(coords) <- c("x", "y")
    output <- tibble::as_tibble(coords) %>%
      dplyr::mutate(name = igraph::vertex_attr(g, "name"))
  } else if (layout == "custom") {
    
    # some argument tests are in here ...

    output <- node_data %>%
      dplyr::select(c(.data$x, .data$y, .data$name))
  }
  return(output)
}

Adding attributes with node_data

The data argument of ggflowchart() passes information about the edges. The optional node_data argument passes information about the nodes.

Adding attributes with node_data

node_layout <- get_layout(
    data = data,
    layout = layout,
    node_data = node_data
    )

add_node_attr <- function(node_layout, node_data) {
  
  # some argument tests are in here ...
  
  node_layout <- dplyr::left_join(node_layout, node_data, by = "name")
  return(node_layout)
}

Adding attributes with node_data

flow_data <- tibble::tribble(
  ~from, ~to,
  "A", "B",
  "B", "C"
)
node_data <- tibble::tribble(
  ~name, ~type, ~x_nudge,
  "A", "Yes", 0.3,
  "B", "Yes", 0.4,
  "C", "No", 0.5
)
ggflowchart(flow_data, node_data, fill = type)

Plotting with {ggplot2}

ggplot() +
  geom_rect(...) +
  geom_text(...) +
  geom_path(...) +
  theme_void(...)

More (and better) examples in vignettes

Adding circular nodes

Adding geoms

ggflowchart(data, node_data = NULL)

ggflowchart(
  data,
  node_data = NULL,
  layout = "tree",
  fill = "white",
  colour = "black",
  alpha = 1,
  text_colour = "black",
  text_size = 3.88,
  parse = FALSE,
  arrow_colour = "black",
  arrow_size = 0.3,
  arrow_linewidth = 0.5,
  arrow_linetype = "solid",
  arrow_label_fill = "white",
  family = "sans",
  x_nudge = 0.35,
  y_nudge = 0.25,
  horizontal = FALSE,
  color = NULL,
  text_color = NULL,
  arrow_color = NULL
)

Adding geoms

Monolithic functions aren’t great…

Adding geoms

Issues to solve:

• colour mapping for geom_nodes(): rectangle outlines or text?

• custom scale_colour_* functions? or suggest {ggnewscale}?

Links

Contact