Fixed Marker Mapping

In Getting Started with ggswim, we showcased how to add markers to a swimmer plot using aesthetic mapping. This is a common use case, but not always the most applicable one. That’s why ggswim also caters to fixed marker assignments.

In this case, fixed marker assignment lets users call add_marker() and pass a single marker at a time with a manually defined color parameter instead of passing a mapped column of values. Let’s see how this works by splitting up infusion_events into distinct data frames.

library(ggswim)
library(ggplot2)

initial_infusions <- infusion_events |>
  dplyr::filter(infusion_type == "Initial Infusion")

initial_infusions |>
  rmarkdown::paged_table()

reinfusions <- infusion_events |>
  dplyr::filter(infusion_type == "Reinfusion")

reinfusions |>
  rmarkdown::paged_table()

We’ll start by setting up the same swimmer plot we’ve made from previous examples. Recall our use of new_scale_color() and sequencing of scale changes:

p <- patient_data |>
  ggswim(
    mapping = aes(
      x = start_time, xend = end_time, y = pt_id,
      color = disease_assessment
    ),
    linewidth = 5
  ) +
  scale_color_manual(
    name = "Overall Disease Assessment",
    values = c("#6394F3", "#F3C363", "#EB792F", "#d73a76", "#85a31e")
  )

Now, building off of this, lets add our initial_infusions and reinfusions markers as separate calls to add_marker():

p +
  # Set a new scale
  new_scale_color() +
  # New manual color markers for Infusions
  add_marker(
    data = initial_infusions,
    aes(x = time_from_initial_infusion, y = pt_id, name = "Initial Infusion"),
    color = "green", size = 5, fixed_marker_name = "Markers"
  ) +
  add_marker(
    data = reinfusions,
    aes(x = time_from_initial_infusion + 2, y = pt_id, name = "Reinfusion"),
    color = "red", size = 5, fixed_marker_name = "Markers"
  ) +
  theme_ggswim()

Notice here how we specified a color outside of aes(), along with a unique aes() param: name. name is required to show static layers in the legend, and also for proper display in cases where a static marker is the first one added. Additionally, we used the parameter fixed_maker_name to set the title of the markers in the legend.

Notes

• It is not recommended to use add_marker() in ggplot layering chains combining both aesthetic mapping and fixed mapping techniques
• When using fixed markers, only one new_scale_color() call is permitted.
• When using fixed markers, only one unique fixed_marker_name is permitted.