Add title and subtitle arguments to g2()

.github/copilot-instructions.md

@@ -155,7 +155,9 @@ Before submitting changes:
 2. Run `R CMD check gglite_*.tar.gz --no-manual` to validate
 3. Ensure all tests pass: `Rscript tests/test-all.R`
 4. Check GitHub Actions status for multi-platform validation
-5. Update `NEWS.md` to document your changes (except for v0.1)
+5. Update `NEWS.md` to document your changes (except for v0.1). **Do NOT add
+   NEWS entries while the package is still at v0.1** — the initial release
+   description is sufficient.
 
 ## Important Conventions
 
@@ -220,12 +222,13 @@ as character strings, e.g., `g2(mtcars, x = 'mpg', y = 'hp')`.
    especially automatically generated ones.
 8. **Testing**: Use testit assertions with proper error handling
 9. **Update NEWS.md**: When making changes, make sure to update `NEWS.md`
-   accordingly to document what changed. The first heading in NEWS.md always
-   represents the dev version and must be of the form `# PKG x.y` where PKG
-   is the package name and x.y is the next version to be released to CRAN
-   (note: x.y, not x.y.0). Usually y is bumped from the current minor
-   version, e.g., if the current dev version is 1.8.3, the next CRAN release
-   is expected to be 1.9.
+   accordingly to document what changed — **except for v0.1** (do NOT add
+   individual change entries for the initial release). The first heading in
+   NEWS.md always represents the dev version and must be of the form
+   `# PKG x.y` where PKG is the package name and x.y is the next version to
+   be released to CRAN (note: x.y, not x.y.0). Usually y is bumped from the
+   current minor version, e.g., if the current dev version is 1.8.3, the next
+   CRAN release is expected to be 1.9.
 
 ## Package API
 

R/gglite.R

@@ -52,6 +52,9 @@ g2_patches_cdn = 'https://cdn.jsdelivr.net/npm/@xiee/utils@v1.14.30/js/g2-patche
 #'   (applied to all sides) or a length-4 vector `c(top, right, bottom, left)`;
 #'   use `NA` to skip individual sides. `NULL` (the default) leaves the value
 #'   unset.
+#' @param title Chart title string, a convenient alternative to piping into
+#'   [title_()] separately.
+#' @param subtitle Chart subtitle string.
 #' @return A `g2` object (S3 class).
 #' @import stats utils
 #' @export
@@ -66,9 +69,13 @@ g2_patches_cdn = 'https://cdn.jsdelivr.net/npm/@xiee/utils@v1.14.30/js/g2-patche
 #' # Time series
 #' g2(sunspot.year)
 #' g2(EuStockMarkets)
+#'
+#' # Title and subtitle
+#' g2(mtcars, hp ~ mpg, title = 'Motor Trend Cars', subtitle = 'mpg vs hp')
 g2 = function(
   data = NULL, ..., width = 640, height = 480,
-  padding = NULL, margin = NULL, inset = NULL
+  padding = NULL, margin = NULL, inset = NULL,
+  title = NULL, subtitle = NULL
 ) {
   dots = list(...)
   has_formula = length(dots) && inherits(dots[[1]], 'formula')
@@ -99,7 +106,7 @@ g2 = function(
     theme = NULL,
     axes = list(),
     legends = list(),
-    chart_title = NULL,
+    chart_title = dropNulls(list(title = title, subtitle = subtitle)),
     facet = facet_from_formula,
     layout = c(
       process_layout('padding', padding),

R/render.R

@@ -120,10 +120,10 @@ build_config = function(chart) {
       config$axis$y = modifyList(as.list(y_ax), list(title = chart$ts_name))
   }
   if (length(chart$legends)) config$legend = chart$legends
-  if (!is.null(chart$chart_title)) config$title = chart$chart_title
-  if (!is.null(chart$tooltip_config)) config$tooltip = chart$tooltip_config
-  if (!is.null(chart$sliders)) config$slider = chart$sliders
-  if (!is.null(chart$scrollbars)) config$scrollbar = chart$scrollbars
+  if (length(chart$chart_title)) config$title = chart$chart_title
+  config$tooltip = chart$tooltip_config
+  config$slider = chart$sliders
+  config$scrollbar = chart$scrollbars
   if (length(chart$layout)) config = modifyList(config, chart$layout)
 
   # Theme: merge global option with per-chart theme

examples/titles-tooltips.Rmd

@@ -8,6 +8,13 @@ library(gglite)
 
 ## Chart Title
 
+### Title and subtitle via `g2()` arguments
+
+```{r}
+g2(mtcars, x = 'mpg', y = 'hp',
+  title = 'Motor Trend Cars', subtitle = 'mpg vs horsepower')
+```
+
 ### Simple title
 
 ```{r}

tests/testit/test-gglite.R

@@ -104,6 +104,18 @@ assert('g2() formula ~ x1 + x2 + x3 sets position encoding', {
   (is.null(chart$aesthetics$x))
 })
 
+assert('g2() title argument sets chart title', {
+  chart = g2(mtcars, x = 'mpg', y = 'hp', title = 'My Title')
+  (chart$chart_title$title %==% 'My Title')
+})
+
+assert('g2() title and subtitle arguments set title and subtitle', {
+  chart = g2(mtcars, x = 'mpg', y = 'hp',
+    title = 'Title', subtitle = 'Subtitle')
+  (chart$chart_title$title %==% 'Title')
+  (chart$chart_title$subtitle %==% 'Subtitle')
+})
+
 # ---- interact() uses named list (object) format ----
 
 assert('interact() stores interaction as named list', {