make sure ioslides_presentation is properly self-contained when req…

…uested (#2428)

Co-authored-by: Yihui Xie <[email protected]>

NEWS.md

@@ -7,6 +7,8 @@ rmarkdown 2.20
 
 - Make sure to avoid creating invalid paths when copying resources (thanks, @mnazarov, #2429).
 
+- Make sure `logo` is properly embedded in `ioslides_presentation()` when `self_contained = TRUE` (thanks, @mnazarov, #2428).
+
 
 rmarkdown 2.19
 ================================================================================

R/ioslides_presentation.R

@@ -332,6 +332,8 @@ ioslides_presentation <- function(number_sections = FALSE,
   if (!length(grep('--wrap', pandoc_args)))
     pandoc_args <- c('--wrap', 'none', pandoc_args)
 
+  logo_placeholder <- "data:,LOGO"
+
   # pre-processor for arguments that may depend on the name of the
   # the input file (e.g. ones that need to copy supporting files)
   pre_processor <- function(metadata, input_file, runtime, knit_meta, files_dir,
@@ -360,7 +362,8 @@ ioslides_presentation <- function(number_sections = FALSE,
         file.copy(from = logo, to = logo_path)
         logo_path <- normalized_relative_to(output_dir, logo_path)
       } else {
-        logo_path <- pandoc_path_arg(logo_path)
+        # placeholder, will be replaced by base64-encoded logo in post_processor
+        logo_path <- logo_placeholder
       }
       args <- c(args, "--variable", paste("logo=", logo_path, sep = ""))
     }
@@ -450,14 +453,18 @@ ioslides_presentation <- function(number_sections = FALSE,
     # read the slides
     slides_lines <- read_utf8(output_tmpfile)
 
+    # read the output file
+    output_lines <- read_utf8(output_file)
+
     # base64 encode if needed
     if (self_contained) {
       slides_lines <- base64_encode_images(slides_lines)
+      if (!is.null(logo)) {
+        logo_base64 <- if (grepl("^data:", logo)) logo else xfun::base64_uri(logo)
+        output_lines <- gsub(logo_placeholder, logo_base64, output_lines, fixed = TRUE)
+      }
     }
 
-    # read the output file
-    output_lines <- read_utf8(output_file)
-
     # substitute slides for the sentinel line
     sentinel_line <- grep("^RENDERED_SLIDES$", output_lines)
     if (length(sentinel_line) == 1) {

tests/testthat/test-ioslides.R

@@ -179,3 +179,31 @@ test_ioslides_presentation_css <- function() {
 
 
 test_that("ioslides presentation is styled", test_ioslides_presentation_css())
+
+test_ioslides_presentation_logo <- function() {
+
+  outputdir <- tempfile()
+  dir.create(outputdir)
+  on.exit(unlink(outputdir), add = TRUE)
+
+  # Generate mock md file with logo
+  void <- file.copy("resources/empty.png", file.path(outputdir, "logo.png"))
+  mdtext <- c("# Slide One\n")
+  mock <- mock_markdown(mdtext = mdtext, outputdir = outputdir, self_contained = TRUE, logo = "logo.png")
+  html <- mock$html_file
+
+  slide_lines <- c(
+    !any(grepl("logo\\.png", html))
+    , any(grep("favIcon: 'data:image/png;base64,[^']*'", html))
+    , any(grepl("background: url\\(data:image/png;base64,[^\\)]*)", html))
+  )
+  expect_true(all(slide_lines), info = "slide lines - self contained logo")
+
+  # if logo is passed as base64 string, do not re-encode
+  logobase64 <- xfun::base64_uri("resources/empty.png")
+  mock2 <- mock_markdown(mdtext = mdtext, outputdir = outputdir, self_contained = TRUE, logo = logobase64)
+  html2 <- mock2$html_file
+  expect_equal(html, html2)
+}
+
+test_that("ioslides presentation embeds logo", test_ioslides_presentation_logo())