Helper function to calculate x-tick positions

Calculate the positions of ticks on the x-axis. However, if xticks already exists it is kept as is. It is based on the same function ggplot2 relies on, and is required in the graphic and the patient-at-risk annotation table.

Usage

h_xticks(data, xticks = NULL, max_time = NULL)

Arguments

data: (data.frame)
survival data as pre-processed by h_data_plot.
xticks: (numeric or NULL)
numeric vector of tick positions or a single number with spacing between ticks on the x-axis. If NULL (default), labeling::extended() is used to determine optimal tick positions on the x-axis.
max_time: (numeric(1))
maximum value to show on x-axis. Only data values less than or up to this threshold value will be plotted (defaults to NULL).

Value

A vector of positions to use for x-axis ticks on a ggplot object.

Examples

library(dplyr)
library(survival)

data <- tern_ex_adtte %>%
  filter(PARAMCD == "OS") %>%
  survfit(formula = Surv(AVAL, 1 - CNSR) ~ ARMCD, data = .) %>%
  h_data_plot()

h_xticks(data)
#> [1]    0 1000 2000 3000 4000 5000
h_xticks(data, xticks = seq(0, 3000, 500))
#> [1]    0  500 1000 1500 2000 2500 3000
h_xticks(data, xticks = 500)
#>  [1]    0  500 1000 1500 2000 2500 3000 3500 4000 4500
h_xticks(data, xticks = 500, max_time = 6000)
#>  [1]    0  500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000
h_xticks(data, xticks = c(0, 500), max_time = 300)
#> [1]   0 500
h_xticks(data, xticks = 500, max_time = 300)
#>  [1]    0  500 1000 1500 2000 2500 3000 3500 4000 4500