From 5412aa6e50d136e409858b850f3319cdf9406392 Mon Sep 17 00:00:00 2001
From: Hendrik Kleinwaechter <hendrik.kleinwaechter@gmail.com>
Date: Fri, 26 May 2023 13:35:04 +0200
Subject: [PATCH] Ebook improvements (#103)

* Ebook improvements

Removes fixed height and width from the resulting HTML and adds an
additional css for the ebook formats.

* Update gitignore

* Strip tags
---
 .gitignore          | 1 +
 book/book-ebook.css | 9 +++++++++
 book/book.mk4       | 9 +++++++++
 book/makefile       | 5 +++--
 book/tex4ebook.cfg  | 1 +
 5 files changed, 23 insertions(+), 2 deletions(-)
 create mode 100644 book/book-ebook.css
 create mode 100644 book/book.mk4

diff --git a/.gitignore b/.gitignore
index bb985d4..d4b68f5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -50,4 +50,5 @@ book/book-mobi/
 book/book-azw3/
 *.bak
 book_sans_serif/
+release_sans_serif/
 *.opf
diff --git a/book/book-ebook.css b/book/book-ebook.css
new file mode 100644
index 0000000..ecc3e08
--- /dev/null
+++ b/book/book-ebook.css
@@ -0,0 +1,9 @@
+.figure {
+    max-width: 100%;
+}
+.figure img {
+    max-width: 100% !important;
+    height: auto;
+    object-fit: contain;
+    width: auto;
+}
diff --git a/book/book.mk4 b/book/book.mk4
new file mode 100644
index 0000000..eb3ff75
--- /dev/null
+++ b/book/book.mk4
@@ -0,0 +1,9 @@
+local filter  = require "make4ht-filter"
+local changePath = function(s) return s:gsub("%./images//","images/") end
+local removeHeight = function(s) return s:gsub('height="%d+"', '') end
+local removeWidth = function(s) return s:gsub('width="%d+"', '') end
+local removeMaxWidth = function(s) return s:gsub(' max-width: %d+px;', '') end
+local removeFixedSettings = function(s) return removeMaxWidth(removeWidth(removeHeight(changePath(s)))) end
+local process = filter{removeFixedSettings}
+Make:htlatex()
+Make:match("html$",process)
diff --git a/book/makefile b/book/makefile
index e257e1a..41e6cc4 100644
--- a/book/makefile
+++ b/book/makefile
@@ -111,8 +111,9 @@ release_sans_serif: make_release_dir
 
 .PHONY: build_ebook
 build_ebook: make_release_dir
-	find . -name "*.jpg" | xargs ebb -x
-	find . -name "*.png" | xargs ebb -x
 	tex4ebook -c tex4ebook.cfg -f epub book.tex
 	tex4ebook -c tex4ebook.cfg -f mobi book.tex
+	# not sure why, but I hvae to generate the mobi twice for the
+	# release command to properly work.
+	tex4ebook -c tex4ebook.cfg -f mobi book.tex
 	tex4ebook -c tex4ebook.cfg -f azw3 book.tex
diff --git a/book/tex4ebook.cfg b/book/tex4ebook.cfg
index b84c63a..53c9efa 100644
--- a/book/tex4ebook.cfg
+++ b/book/tex4ebook.cfg
@@ -3,6 +3,7 @@
 \Configure{DocumentLanguage}{en}
 \Configure{OpfScheme}{URI}
 \Configure{UniqueIdentifier}{https://the-bread-code.io}
+\Configure{AddCss}{book-ebook.css}
 \Configure{CoverMimeType}{image/jpeg}
 \CoverMetadata{images/cover-page.jpg}
 \EndPreamble