nicoverbruggen/kobalt v1.0-beta.4

Kobalt v1.0-beta.4

on GitHub

What's new

Key features

• Annotations are here: save shaded highlights, solid underlines or dotted underlines. Enable annotation mode in the reading menu, then long-press a word to start selecting. Colour displays offer yellow, green, blue, pink and gray.

• Customize the header and footer from Layout. Choose Kobalt, Bookish, Ember or Custom, then select what appears in each left, center and right slot. Fields include the clock, battery, chapter and book progress, and estimated time left. (The default Kobalt layout has been adjusted.)

• Advanced typography in Settings > Styling: adjust word spacing, justification tracking, and widow/orphan handling. Descriptions and illustrations explain the choices; text samples use the current book's font. Justification tracking affects only justified text; it is off by default. Widow/orphan handling follows the publisher by default.

• Two-column landscape reading in Settings > Display. Portrait stays in one column, and the column gap can be adjusted as a multiple of the text size. The default gap is 1.5×.

• Thumbnail navigation has been added as a tab ("Navigate"): it shows the selected page with neighbouring previews and a book map. Swipe or tap the side previews to move through pages, then tap the middle preview to go there. Page buttons navigate the previews while Navigate is open. Return to page takes you back after a bookmark or link jump.

• Customize how page turns work. Choose how to turn pages in Settings > Controls: swipes and taps, taps only, swipes only, or hardware buttons only on supported devices. Tap zones include Left / right, Reversed, Top / bottom and One-handed.

• New books can inherit the last book's text style. Layout margins apply across books, and header/footer presets can be inherited separately. Settings > Defaults controls inheritance.

• An opt-in Kobalt-specific sleep screen has been added. Choose Kobo's standard sleep screen, the book cover or a dimmed reading page while using Kobalt. The Kobalt screens show reading progress and time left. Kobo's standard screen remains the default.

Other additions

• Reading data (including the new annotations) now uses SQLite. Repeated layout and metadata work has also been reduced.

• Rendering caches use a compatibility version rather than the app version, avoiding unnecessary cache rebuilds on later compatible updates.

• Follow Kobo warmth schedule in the Light panel uses the bedtime configured in Kobo's settings. Manual warmth adjustments turn the schedule off until you enable it again.

• More interface customization, including separate interface typefaces and header/footer weight. Settings and confirmation dialogs use consistent controls and a patterned backdrop. Paged lists show a hint when more items are available.

• Smart Styling, enabled by default, reduces wasted space from publisher page-break spacing and body margins. Turn it off in Settings > Styling to preserve that formatting.

• Text size now adjusts in half-point steps below 32 pt, making smaller reading sizes easier to fine-tune.

• Added an Every page full-refresh option in Settings > Display.

• Optional global custom CSS in .adds/kobalt/userstyle.css lets you add your own book styling. Experimental.

What's fixed

• Improved rendering of Arabic text, mathematical notation, fallback bold and italic faces, and special Unicode spaces. Full-page SVG images and chapter tables keep their alignment.

• Fixed reversed paragraph indentation at some text sizes, and restored publisher spacing and drop-cap layout in affected Kobo books.

• Footnote popups recognize more numbered, lettered and superscript references, including unmarked endnotes. Long-pressing a word in a link offers dictionary lookup or following the link without entering annotation mode.

• Marking a book unread resets its reading position and book-specific settings while keeping bookmarks and annotations. Kobalt also respects a book marked unread in Kobo's own library when it is next opened.

• Page turning works again after cancelling the USB screen and unplugging. Sleep, wake and rotation handoffs have also been improved.

• Kobo custom dictionaries can be selected alongside a standard dictionary for the same language, including when the standard dictionary is not installed.

• Fixed incorrect touch positioning in landscape on Kobo Clara HD.

Android

• An experimental, signed Android release is available for Android 9 or later on ARM64 devices. It includes a Library with folder scanning, search, sorting, cover and list views. Books opened through the document picker or another app's Open with menu join the Library automatically.

• This version was tested on a BOOX Go 7 (it has some BOOX specific adjustments) and a Google Pixel 9a. The UI is not optimized for phones and may require some tinkering to look good. I recommend disabling the header for phones with a camera in the status bar, or a notch.

• Android remembers reading speed across books and app sessions. Time estimates adapt as you read and show ≈ while history is limited. Reading positions, bookmarks and annotations stay on the device.

Installation on Kobo

For Kobo, the easiest method is Install or remove on Kobo in Chrome. For manual installation, download the package for your firmware:

• Kobalt-qt5.zip for firmware 4.38.21908 and later 4.x, tested up to 4.46.
• Kobalt-qt6.zip for firmware 5.18 and later 5.x, and 6.x, tested up to 6.0.2.

Manual installation instructions

1. Connect your Kobo over USB and extract the ZIP on your computer. Show hidden files to see .adds and .kobo.
2. Copy .adds to the root of the Kobo drive. Merge folders and replace matching package files. Keep other apps, settings and reading data.
3. Then copy .kobo to the same drive root, merging folders again.
4. Eject the Kobo safely, disconnect USB and let the update install.

Copy both folders in that order. Leave the .tgz file inside .kobo compressed.

Upgrading from beta 3

Upgrading should be seamless: you can upgrade over the existing installation and keep .adds/kobalt; a clean install is not required. The easiest way to upgrade is via the website.

Existing reading positions, book settings and bookmarks are imported automatically into kobalt.sqlite. Migrated files are retained under migration-backup/. Global preferences remain in reader-settings.json. (If you need to return to beta 3, use your pre-upgrade backup!)

Installation on Android

Download Kobalt-android-arm64.apk and install it manually. Allow installation from the app you use to open the APK if Android asks. This and future Android releases remain experimental.

Build details

Checksums · Build information: Qt5, Qt6, Android

Source code and dependencies

Full Changelog: v1.0-beta.3...v1.0-beta.4