From afc552b89fab02101345ff3a8f5b92f28919c12c Mon Sep 17 00:00:00 2001
From: John MacFarlane <jgm@berkeley.edu>
Date: Wed, 17 Apr 2024 23:12:56 -0700
Subject: [PATCH] LaTeX writer: include `\pandocbounded` with image commands...

unless a height/width is specified.
---
 src/Text/Pandoc/Writers/LaTeX.hs |  7 +++++--
 test/command/3450.md             |  2 +-
 test/writer.latex                | 18 ++++++++++--------
 3 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/src/Text/Pandoc/Writers/LaTeX.hs b/src/Text/Pandoc/Writers/LaTeX.hs
index e347d240be062..2c5f71819637f 100644
--- a/src/Text/Pandoc/Writers/LaTeX.hs
+++ b/src/Text/Pandoc/Writers/LaTeX.hs
@@ -1094,8 +1094,11 @@ inlineToLaTeX (Image attr@(_,_,kvs) _ (source, _)) = do
   inHeading <- gets stInHeading
   return $
     (if inHeading then "\\protect" else "") <>
-      (if isSVG then "\\includesvg" else "\\includegraphics") <>
-    options <> braces (literal source'')
+    (case dimension Width attr `mplus` dimension Height attr of
+       Nothing -> id
+       Just _ -> ("\\pandocbounded" <>) . braces)
+      ((if isSVG then "\\includesvg" else "\\includegraphics") <>
+        options <> braces (literal source''))
 inlineToLaTeX (Note contents) = do
   setEmptyLine False
   externalNotes <- gets stExternalNotes
diff --git a/test/command/3450.md b/test/command/3450.md
index 5ccfd05ff6e9b..2a96c911b90a9 100644
--- a/test/command/3450.md
+++ b/test/command/3450.md
@@ -8,5 +8,5 @@
 % pandoc -fmarkdown-implicit_figures -t latex
 ![image](lalune.jpg){height=2em}
 ^D
-\includegraphics[width=\textwidth,height=2em]{lalune.jpg}
+\pandocbounded{\includegraphics[width=\textwidth,height=2em]{lalune.jpg}}
 ```
diff --git a/test/writer.latex b/test/writer.latex
index b1d784f02cf79..d0beec0679cd7 100644
--- a/test/writer.latex
+++ b/test/writer.latex
@@ -39,15 +39,17 @@
 \usepackage{xcolor}
 \usepackage{graphicx}
 \makeatletter
-\def\maxwidth{\ifdim\Gin@nat@width>\linewidth\linewidth\else\Gin@nat@width\fi}
-\def\maxheight{\ifdim\Gin@nat@height>\textheight\textheight\else\Gin@nat@height\fi}
-\makeatother
-% Scale images if necessary, so that they will not overflow the page
-% margins by default, and it is still possible to overwrite the defaults
-% using explicit options in \includegraphics[width, height, ...]{}
-\setkeys{Gin}{width=\maxwidth,height=\maxheight,keepaspectratio}
+\newsavebox\pandoc@box
+\newcommand*\pandocbounded[1]{% scales image to fit in text height/width
+  \sbox\pandoc@box{#1}%
+  \Gscale@div\@tempa{\textheight}{\dimexpr\ht\pandoc@box+\dp\pandoc@box\relax}%
+  \Gscale@div\@tempb{\linewidth}{\wd\pandoc@box}%
+  \ifdim\@tempb\p@<\@tempa\p@\let\@tempa\@tempb\fi% select the smaller of both
+  \ifdim\@tempa\p@<\p@\scalebox{\@tempa}{\usebox\pandoc@box}%
+  \else\usebox{\pandoc@box}%
+  \fi%
+}
 % Set default figure placement to htbp
-\makeatletter
 \def\fps@figure{htbp}
 \makeatother
 \ifLuaTeX