From d0009c01b019fe9d4fb34194120702b87030465e Mon Sep 17 00:00:00 2001
From: Timo Heister <timo.heister@gmail.com>
Date: Tue, 22 Jan 2019 12:32:03 -0700
Subject: [PATCH] doxygen: add missing newcommand for HTML output

latex formulas in doxygen HTML output without mathjax would not work
because of a missing newcommand. This is now fixed.
---
 doc/doxygen/CMakeLists.txt           |  3 +++
 doc/doxygen/extra.sty                | 21 +++++++++++++++++++++
 doc/doxygen/options.dox.in           |  2 +-
 doc/doxygen/scripts/mod_header.pl.in |  2 ++
 4 files changed, 27 insertions(+), 1 deletion(-)
 create mode 100644 doc/doxygen/extra.sty

diff --git a/doc/doxygen/CMakeLists.txt b/doc/doxygen/CMakeLists.txt
index 6e067ebc8f..c008c0ffd0 100644
--- a/doc/doxygen/CMakeLists.txt
+++ b/doc/doxygen/CMakeLists.txt
@@ -101,6 +101,9 @@ ENDFOREACH()
 MESSAGE(STATUS "translated this into")
 MESSAGE(STATUS "found ${_inst_in_dirs}")
 
+# make sure doxygen sees the extra.sty stylefile:
+SET(_extra_packages "${CMAKE_CURRENT_SOURCE_DIR}/extra")
+
 # Generate the input files for doxygen using template .in files in which
 # we have to substitute some CMake variables
 CONFIGURE_FILE(
diff --git a/doc/doxygen/extra.sty b/doc/doxygen/extra.sty
new file mode 100644
index 0000000000..77a56b30ac
--- /dev/null
+++ b/doc/doxygen/extra.sty
@@ -0,0 +1,21 @@
+% ---------------------------------------------------------------------
+%
+% Copyright (C) 2019 by the deal.II authors
+%
+% This file is part of the deal.II library.
+%
+% The deal.II library is free software; you can use it, redistribute
+% it, and/or modify it under the terms of the GNU Lesser General
+% Public License as published by the Free Software Foundation; either
+% version 2.1 of the License, or (at your option) any later version.
+% The full text of the license can be found in the file LICENSE.md at
+% the top level directory of deal.II.
+%
+% ---------------------------------------------------------------------
+
+% export dealcoloneq (this file is used when generating the formulas as images
+% in the doxygen HTML output (without mathjax).
+
+% Note: If you add an entry here, also put it into
+% ./doc/doxygen/scripts/mod_header.pl.in
+\newcommand{\dealcoloneq}{\mathrel{\vcenter{:}}=}
diff --git a/doc/doxygen/options.dox.in b/doc/doxygen/options.dox.in
index c82df40360..6665e1cba6 100644
--- a/doc/doxygen/options.dox.in
+++ b/doc/doxygen/options.dox.in
@@ -134,7 +134,7 @@ GENERATE_LATEX         = NO
 # but set a few flags for when processing formulas embedded
 # in the documentation.
 PAPER_TYPE             = a4wide
-EXTRA_PACKAGES         = amsmath amsfonts mathtools
+EXTRA_PACKAGES         = amsmath amsfonts mathtools @_extra_packages@
 LATEX_BATCHMODE        = YES
 
 #---------------------------------------------------------------------------
diff --git a/doc/doxygen/scripts/mod_header.pl.in b/doc/doxygen/scripts/mod_header.pl.in
index 5e7e523f83..55cb1d3de0 100644
--- a/doc/doxygen/scripts/mod_header.pl.in
+++ b/doc/doxygen/scripts/mod_header.pl.in
@@ -37,6 +37,8 @@ s/\$projectname// unless (m/<title>/);
 # Finally, define some extra commands for MathJax in every file. These are in an
 # undisplayed div so that the \newcommand text does not pop up and then
 # disappear while MathJax works.
+#
+# Note: If you add an entry here, also put it into ./doc/doxygen/extra.sty
 if (eof)
 {
     print '<!--Extra macros for MathJax:-->', "\n";
-- 
2.39.5