Skip to content

Extra white space after non-breaking hyphens on the Kobo build #801

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom
Open
Kos opened this issue Mar 9, 2025 · 1 comment
Open

Extra white space after non-breaking hyphens on the Kobo build #801

Kos opened this issue Mar 9, 2025 · 1 comment

Comments

@Kos
Copy link

Kos commented Mar 9, 2025

Symptom

When the kepub (se) build is viewed on a kobo device, there's extra white space included after a word containing non-breaking hyphens.

The same issue is not observed on the epub build or the kepub build created using kepubify.

Correct:

Image

Incorrect:

Image

Complete test case available on this branch: https://github.com/Kos/jules-verne_robur-the-conqueror/tree/whitespace-rendering-test

XHTML differences

Example line in source and epub:

<p>And the inexplicable <i>f‑r‑r‑r‑r</i> seemed to sweep along below it.</p>

The same line in kepub (se):

<p><span id="kobo.12.1" class="koboSpan">And the inexplicable </span><i><span id="kobo.12.2" class="koboSpan">f⁠-⁠r⁠-⁠r⁠-⁠r⁠-⁠r</span></i><span id="kobo.13.1" class="koboSpan"> seemed to sweep along below it.</span></p>

The same line in kepub (kepubify):

<p><span class="koboSpan" id="kobo.5.1">And the inexplicable </span><i><span class="koboSpan" id="kobo.5.2">f‑r‑r‑r‑r</span></i><span class="koboSpan" id="kobo.5.3"> seemed to sweep along below it.</span></p>

The changes seem structurally the same; only numerical IDs are different.

CSS differences

core.css has some ines removed in kepub (se):

--- "test case.epub.d/epub/css/core.css"        2025-03-08 16:00:02.000000000 +0100
+++ "test case.kepub.epub.d/epub/css/core.css"  2025-03-08 16:00:02.000000000 +0100
@@ -4,9 +4,6 @@
 body{
        font-variant-numeric: oldstyle-nums;
        hyphens: auto;
-       adobe-hyphenate: auto;
-       -webkit-hyphens: auto;
-       -moz-hyphens: auto;
        -epub-hyphens: auto;
        text-wrap: pretty;
 }
@@ -55,10 +52,6 @@
        page-break-inside: avoid;
        font-variant: small-caps;
        hyphens: none;
-       adobe-text-layout: optimizeSpeed; /* For Nook */
-       adobe-hyphenate: none;
-       -webkit-hyphens: none;
-       -moz-hyphens: none;
        -epub-hyphens: none;
        margin-top: 3em;
        margin-right: 0;
@@ -168,10 +161,6 @@
        break-inside: avoid;
        page-break-inside: avoid;
        hyphens: none;
-       adobe-text-layout: optimizeSpeed; /* For Nook */
-       adobe-hyphenate: none;
-       -webkit-hyphens: none;
-       -moz-hyphens: none;
        -epub-hyphens: none;
        text-align: center;
 }

core.css is unchanged in kepubify.

se.css has some adjustments in kepub (se):

--- "test case.epub.d/epub/css/se.css"  2025-03-08 16:00:02.000000000 +0100
+++ "test case.kepub.epub.d/epub/css/se.css"    2025-03-08 16:00:02.000000000 +0100
@@ -73,10 +73,6 @@
 section.epub-type-imprint a,
 section.epub-type-colophon a{
        hyphens: none;
-       adobe-text-layout: optimizeSpeed; /* For Nook */
-       adobe-hyphenate: none;
-       -webkit-hyphens: none;
-       -moz-hyphens: none;
        -epub-hyphens: none;
 }
 
@@ -94,7 +90,7 @@
        text-indent: 0;
 }
 
-section.epub-type-copyright-page blockquote p span{
+section.epub-type-copyright-page blockquote p span.se{
        display: block;
        padding-left: 1em;
        text-indent: -1em;
@@ -102,4 +98,13 @@
 
 section.epub-type-copyright-page blockquote br{
        display: none;
-}
\ No newline at end of file
+}
+
+/* Kobo compatibility CSS */
+
+section[epub|type~="titlepage"] h1,
+section[epub|type~="titlepage"] p,
+section[epub|type~="colophon"] h2,
+section[epub|type~="imprint"] h2{
+       font-size: 0; /* Required for Kobo not to add an extra page to the title */
+}

se.css is again unchanged in kepubify.

testcase.xhtml has some css added by kepubify, but it looks irrelevant:

--- "test case.epub.d/epub/text/testcase.xhtml" 2025-03-08 16:00:02.000000000 +0100
+++ "test case_kepubify.kepub.epub.d/epub/text/testcase.xhtml"  2025-03-08 17:00:02.000000000 +0100
@@ -1,30 +1,29 @@
-<?xml version="1.0" encoding="utf-8"?>
-<html xmlns="http://www.w3.org/1999/xhtml" xmlns:epub="http://www.idpf.org/2007/ops" lang="en-US" epub:prefix="z3998: http://www.daisy.org/z3998/2012/vocab/structure/, se: https://standardebooks.org/vocab/1.0" xml:lang="en-US">
-       <head>
+<?xml version="1.0" encoding="utf-8"?><html xmlns="http://www.w3.org/1999/xhtml" xmlns:epub="http://www.idpf.org/2007/ops" lang="en-US" epub:prefix="z3998: http://www.daisy.org/z3998/2012/vocab/structure/, se: https://standardebooks.org/vocab/1.0" xml:lang="en-US"><head>
                <title>Chapter</title>
                <link href="../css/core.css" rel="stylesheet" type="text/css"/>
                <link href="../css/local.css" rel="stylesheet" type="text/css"/>
-       </head>
-       <body epub:type="bodymatter z3998:fiction">
+       <style type="text/css" class="kobostylehacks">div#book-inner { margin-top: 0; margin-bottom: 0;}</style></head>
+       <body epub:type="bodymatter z3998:fiction"><div id="book-columns"><div id="book-inner">
                <section id="chapter-6" role="doc-chapter" epub:type="chapter">
@acabal
Copy link
Member

acabal commented Mar 10, 2025

Again, this is an issue with the renderer used by Kobo. When you open a regular epub, you trigger the ADE renderer which is very limited. When you open a kepub, you trigger their advanced renderer which is based on Webkit. The two renderers will render the same epub in very different ways and that's a Kobo problem.

Since you already have the test cases lined up, why don't you continue digging to see exactly which difference is causing these issues?

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Assignees
No one assigned
Labels
None yet
Projects
None yet
Milestone
No milestone
Development

No branches or pull requests
2 participants
@acabal @Kos