Need to round before indexing month (#383)

NEWS.md

@@ -39,6 +39,8 @@ treated as dates ([#356](https://github.com/angusmoore/arphit/pull/356))
 * Fixed autolabeller failure when have to identical column series ([#324](https://github.com/angusmoore/arphit/pull/324))
 * Underscores in titles no longer throw errors for unknown width ([#337](https://github.com/angusmoore/arphit/pull/337))
 * Better vertical spacing of footnotes, sources, and axis labels ([#342](https://github.com/angusmoore/arphit/pull/342))
+* Correct month labels with high-resolution (e.g. hourly) data; previously showed one month offset
+([#383](https://github.com/angusmoore/arphit/pull/383))
 
 ## Deprecated or removed
 

R/axes.R

@@ -388,7 +388,7 @@ xlabels.ts_month <- function(xlim) {
 
   # convert the labels to month letters
   months <- seq(from = 1 + (startmonth-floor(startmonth)) * 12, length.out = length(ticks))
-  labels <- substr(month.abb[1 + (months - 1) %% 12], 1, 1)
+  labels <- substr(month.abb[round(1 + (months - 1) %% 12)], 1, 1)
   at <- ticks + 0.5 * 1/12
 
   # add years

tests/testthat/test-axes.R

@@ -303,6 +303,21 @@ test_that("Miscellaneous x axis tests", {
   )
 })
 
+# incorrect rounding for months with hourly data (#381)
+test_that("months with hourly data", {
+  set.seed(42)
+  data <- tibble(
+    date = seq(lubridate::parse_date_time('2014-02-01 00:00', 'Ymd HM'),
+               by = '1 hour',
+               length.out = 1000),
+    value = cumsum(rnorm(1000))
+  )
+  p <- data %>%
+    arphitgg(agg_aes(x=date, y=value)) +
+    agg_line()
+  expect_true(check_graph(p, "axes-month-hourly-data-381"))
+})
+
 ## Unit handling ===============
 test_that("Units", {
   p <- arphitgg() + agg_units("foo")