Calibre 2.0 soft hyphenation handling seems to have changed

[Katsunami]

Today I've updated to Calibre version 2.0. While putting some books into shape, I've noticed that the lines were all out of sorts. They lost their justification on the right, and now display ragged. It comes down to using Hyphenate This, which is a plugin that puts soft hyphens into the text. See the attachments:

soft_hyphens_none.png: without soft hyphens
soft_hyphens_yes.png: with soft hyphens

After putting in the soft hyphens, the lines get out of wack, and get justified properly when removing the hyphens. I'm seeing this issue in both the Calibre Viewer, and the Ebook Editor, and with all books I've tested (all EPUB).

If necessary, I could return to version 1.48 to test and be 100% sure, but I'm quite certain I've never seen this before.

[kovidgoyal]

Attach a book where you see the incorrect justification behavior.

[Katsunami]

Here you go

Another screenshot, of a different book (and the book itself). Left shows the book before Hyphenate This! applied, right shows it with. AFAIK, the plugin hasn't changed for ages apart from the conversion to QT5, and I have not seen anything weird after that, using Calibre 1.48.

PS: I remember that Sigil had this exact same issue, so it may have something to do with the settings or configuration of the browser component.

[Katsunami]

To be 100% sure, I have installed Calibre 1.48 Portable.

This viewer handles the hyphens as expected; in the attachment below you can see the viewer of Calibre 1.48, without hyphens left, and with hyphens right.

The book is the same as the one linked above.

[kovidgoyal]

Again, looks fine for me, see screenshot of hyphens_yes.epub

Try restoring the viewer preferences to defaults and see if that makes a difference.

[Katsunami]

I have reset the viewer to the default settings, and at first, that seems to have fixed the problem, but there is still a difference between the 1.48 and 2.0 viewer.

DejaVu Serif and DejaVu Sans work in both 1.48 and 2.0.
Gentium Basic works in both 1.48 and 2.0

However, Verdana works in 1.48, but not 2.0.
Constantia works in 1.48, but not in 2.0.
Georgia... Same deal.

The viewer in Calibre 2.0 seems to have problems with some fonts in combination with soft-hyphens, while the viewer in 1.48 does not.

[kovidgoyal]

This is most definitely a Qt 5 bug, there are dozens of these, most of them I have managed to workaround, a few, like this one, I cannot. I suggest you use the fonts that work and wait until Qt gets around to fixing this issue.

Text rendering in Qt is a real crapshoot, there are many text rendering bugs that Qt 5 fixed over Qt 4, and some that it introduced.

EDIT: see https://bugreports.qt-project.org/browse/QTBUG-40912

[Katsunami]

OK, thanks for looking into it

If it's just cosmetic, I'll just switch to a working font. I don't actually read in the viewer anyway; I use it to see if everything is in order after I edited a book. I can do it faster there than in the editor itself.

Weird bug though... But then again, I'm not a font rendering expert.

Don't you sometimes hate (developing) software? Be honest, sometimes you do I know I sometimes wish the computer was never invented

[kovidgoyal]

I usually only hate developing software when I have to deal with large blobs of code written in legacy languages like C/C++ (Qt is the biggest such culprit). They are very hard to debug, have all sorts of logic errors, tend to crash with segmentation violations all the time and are developed glacially thanks to the highly inefficient languages they are written in.

[Katsunami]

LOL. I like C and C++, for writing embedded software (without gui) that has to be extremely small and fast . If I had to write a desktop application in one of them nowadays, I'd probably prefer to shoot myself though

I'll drop the other pending reports on the viewer and editor then, because I expect they are all caused by the same bug(s) in QT5.

[kovidgoyal]

Sure C/C++ have their place. Desktop software is not that place.