Hyphenation in Viewer - 2024

[413Michele]

I'm starting this thread as a follow up to this 2019 one. At the time the situation was much more dire, with Chromium not having support for hyphenation at all and the lack of hyphenation dictionaries for the vast majority of languages.

Right now, however, it seems like all the pieces necessary for a seamless integration of automatic hyphenation in the calibre Viewer are present:

• Chromium supports hyphenation since version 88 and has added many dictionaries in subsequent versions (v112 in particular)
• From what I understand, calibre currently runs on Qt 6.4 i.e. the Chromium version of the bundled QtWebEngine is v102, more than enough to support many languages (though not all the ones supported in v112)
• The CSS property for hyphens is now standardised and its prefixed versions not necessary anymore, at least as far as the Viewer is concerned

The only doubt I have is whether QtWebEngine actually added support for hyphenation at all. I can see no reason not to do this, yet I couldn't find any info on it, and the fact that calibre's Viewer doesn't already seamlessly support hyphenation may indicate that the problem lies with QTWebEngine and not with how it's implemented in the Viewer.

This may well be a question of personal preference, but I believe automatic hyphenation would be a very nice feature that for some languages would yield a marked improvement in readability. If this is considered too disruptive to be made a GUI option, it could simply be allowed as Custom CSS, away from a general user's reach.

Given this new situation, is there a reasonable possibility that the calibre Viewer may support this?

[kovidgoyal]

I dont know of a way to get Qt WebEngine to use hyphenation dictionaries on any platform other than macOS where IIRC it can use the native hyphenation framework for it.

If you do, I am all ears.

[413Michele]

That is a pity :(

So the problem lies with QtWebEngine. Do you know any more about it, particularly whether they implement hyphenation at all? Because the dictionaries should get shipped along with Chromium.

I don't think I'm the best person to investigate this but I surely want to try, and any info is welcome

[kovidgoyal]

No clue, last I looked into this, IIRC I could find only spelling dictionary support not hyphenation.

Not that you can use the calibre content server viewr with a web browser to read books with hyphenation.

[413Michele]

A small update:

I searched through the QT bug tracker but I found almost nothing. There appears to be the possibility of importing/loading dictionaries, but only for spell checking, which is a pity considering some dictionaries also contain hyphenation rules.

I opened a thread here on the QT forums to ask for information, but as of now I got no answer, so for now that's it.