close #2276: issue a warning message in case of chunk options webshot…

… = 'webshot2' and dev = 'pdf'

DESCRIPTION

@@ -1,7 +1,7 @@
 Package: knitr
 Type: Package
 Title: A General-Purpose Package for Dynamic Report Generation in R
-Version: 1.43.7
+Version: 1.43.8
 Authors@R: c(
     person("Yihui", "Xie", role = c("aut", "cre"), email = "xie@yihui.name", comment = c(ORCID = "0000-0003-0645-5666")),
     person("Abhraneel", "Sarma", role = "ctb"),

NEWS.md

@@ -22,6 +22,8 @@
 
 - In-body chunk options (`#|`) are now preserved when extracting code from a document via `purl()` (thanks, @LuisLauM, #2268).
 
+- A warning message will be issued when taking screenshots for HTML widgets in PDF with the **webshot2** package, because **webshot2** doesn't use the correct figure size at the moment (thanks, @icejean, #2276).
+
 # CHANGES IN knitr VERSION 1.43
 
 ## NEW FEATURES

R/plot.R

@@ -611,6 +611,11 @@ html_screenshot = function(x, options = opts_current$get(), ...) {
   w = webshot_available()
   webshot = c(options$webshot, names(w)[w])
   webshot = if (length(webshot) == 0) 'webshot' else webshot[[1L]]
+  if (webshot == 'webshot2' && ext == 'pdf' && getOption('knitr.warn.webshot2', TRUE)) warning(
+    "webshot2 may take the PDF screenshot with the wrong size. You are recommended ",
+    "to use the 'png' format instead (i.e., set the chunk option dev = 'png'). ",
+    "See https://github.com/yihui/knitr/issues/2276 for more information."
+  )
   f = in_dir(d, {
     if (i1 || i3) {
       if (i1) {