From 1b90bf669b52bef59f3cf152a5de3e6bfe97ae21 Mon Sep 17 00:00:00 2001
From: Cedric <ced@sdf.org>
Date: Sat, 18 Jan 2025 15:14:34 +0000
Subject: [PATCH] Use sans-serif fonts with tex4ht

This has to be done in the config file..:

All fonts are suppressed in the --lua mode of TeX4ht, because we need to
prevent the loading of OpenType fonts, which causes a fatal error.:
https://tex.stackexchange.com/questions/705948/change-font-of-tikz-diagrams-in-html-produced-by-make4ht
---
 book/tex4ebook.cfg | 8 ++++++++
 book/website.cfg   | 8 ++++++++
 2 files changed, 16 insertions(+)

diff --git a/book/tex4ebook.cfg b/book/tex4ebook.cfg
index 43adcf52..dffea80e 100644
--- a/book/tex4ebook.cfg
+++ b/book/tex4ebook.cfg
@@ -11,4 +11,12 @@
 \Configure{AddCss}{book-ebook.css}
 \Configure{CoverMimeType}{image/jpeg}
 \CoverMetadata{cover/cover-page.jpg}
+\AddToHook{env/tikzpicture/begin}{\fontfamily{opensans-TLF}\selectfont}
+\Configure{@HEAD}{\HCode{
+<style type="text/css">
+  @import url('https://fonts.cdnfonts.com/css/open-sans');
+  body{
+    font-family: 'Open Sans';
+  }
+</style>}}
 \EndPreamble
diff --git a/book/website.cfg b/book/website.cfg
index aa159215..f236b6e6 100644
--- a/book/website.cfg
+++ b/book/website.cfg
@@ -9,6 +9,14 @@
 }} 
 
 \Configure{AddCss}{style.css}
+\AddToHook{env/tikzpicture/begin}{\fontfamily{opensans-TLF}\selectfont}
+\Configure{@HEAD}{\HCode{
+<style type="text/css">
+  @import url('https://fonts.cdnfonts.com/css/open-sans');
+  body{
+    font-family: 'Open Sans';
+  }
+</style>}}
 \ConfigureEnv{titlepage}{\ifvmode\IgnorePar\fi\EndP\HCode{<main class="titlepage">}}{\ifvmode\IgnorePar\fi\EndP\HCode{</main>}}{}{}
 
 % Mini TOC