Polish list, loops, & map() intro.

images/embed_jpg.R

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+is_latex <- function() {
+  identical(knitr::opts_knit$get('rmarkdown.pandoc.to'), "latex")
+}
+
+embed_jpg <- function(path, dpi) {
+  dim <- jpg_dim(path)
+
+  if (is_latex()) {
+    width <- round(dim[2] / dpi, 2)
+
+    knitr::asis_output(paste0(
+      "\\includegraphics[",
+      "width=", width, "in",
+      "]{", path, "}"
+    ))
+  } else {
+    knitr::asis_output(paste0(
+      "<img src='", path, "'",
+      " width='", round(dim[2] / (dpi / 96)), "'",
+      " height='", round(dim[1] / (dpi / 96)), "'",
+      " />"
+    ))
+  }
+}
+
+jpg_dim <- function(path) {
+  dim(jpeg::readJPEG(path, native = TRUE))
+}