Calibre 8 : Improved Kobo support

[jjk]

Dear Kovid
In changelog for 8.01 you say : Much improved Kobo support. Thanks and cheers.
Can you tell us what is new in Kobo support ?

[PeterT]

Simply put; the need for the Kobo Touch EXTENDED drivers has been removed (in fact those plugins will no longer load in calibre); their functionality is now native to calibre.

Additionally both the Viewer and Editor support kepub formats.

[remlap]

Do well need the KoboUtilities plugin any longer?

[theducks]

Originally Posted by remlap

Do well need the KoboUtilities plugin any longer?

Maybe
Depends on what you used (item on menu) it for.

[remlap]

Originally Posted by theducks

Maybe
Depends on what you used (item on menu) it for.

I have just removed the plugin and figured out the subtitles column and everything is fine.

[shopma2]

Hi
When I load an epub from calibre 8 to my Kobo it is displayed with a much smaller font on the Kobo than books from the previous calibre version. In the calibre epub editor on my PC the font size is NOT different.
When I copy the epub from the Kobo back to the PC and view it the font size is normal.
When I uninstall calibre 8 and use calibre 7.26 to load the ebup on the Kobo the problem does not occur.

[kovidgoyal]

Originally Posted by shopma2

Hi
When I load an epub from calibre 8 to my Kobo it is displayed with a much smaller font on the Kobo than books from the previous calibre version. In the calibre epub editor on my PC the font size is NOT different.
When I copy the epub from the Kobo back to the PC and view it the font size is normal.
When I uninstall calibre 8 and use calibre 7.26 to load the ebup on the Kobo the problem does not occur.

That's a difference between how Kobo renders KEPUB and EPUB. Either adjust the font size in the kobo settings to what you prefer or turn of using KEPUB in the kobo driver preferences.

[DNSB]

Originally Posted by shopma2

Hi
When I load an epub from calibre 8 to my Kobo it is displayed with a much smaller font on the Kobo than books from the previous calibre version. In the calibre epub editor on my PC the font size is NOT different.
When I copy the epub from the Kobo back to the PC and view it the font size is normal.
When I uninstall calibre 8 and use calibre 7.26 to load the ebup on the Kobo the problem does not occur.

You can either uncheck Use Kobo viewer for EPUB books to disable the conversion to kepub.epub or use the KoboPatcher Unify Font Sizes patch to make the base font size in ePub and Kepub books match. The patch is the solution I use since it allows me to switch renderers without a noticeable font size change.

Kobo uses 2 renderers, one is the Adobe RMSDK renderer which is needed to compatibility with ePubs that use Adobe's ADEPT DRM while the other is WebKit based with much better ePub3 support which supports Kobo's proprietary DRM.

Unify font sizes:
  - Enabled: no
  - Description: |
      Attempt to unify the font sizes between epub and kepub. Without this patch
      epub font sizes can be much larger than kepub at the same size setting.
    # From my current understanding, the final font size for epubs is calculated
    # as follows: ( font_size / scale_factor ) * DPI, where 'scale_factor' =
    # 25.0. It seems RMSDK must be handling DPI elsewhere however, because the
    # DPI multiplication here seems to have a detrimental effect, and behaves
    # differently on different devices. This patch changes the 'scale_factor' to
    # 2.5, and replaces the call to get DPI with a constant multiplier (16).
    # The results of using these values are equivalent to  
    # ( font_size / 15.0 ) * 96 which is what I suspect the kepub formula is.
    # Note, that the replacement values are limited to 0.25 - 31.0 in 0.25
    # increments.
    #
    # Refer to https://github.com/pgaskin/kobopatch-patches/issues/96 for more
    # information.
  # EPUB settings:
  - BaseAddress:
      Sym: "AdobeStyling::update(QString const&)"
      Rel: 5796 # at ReadingSettings::getReadingFontSizeScaleFactor(float, float)
  # Set the scale factor to 2.5
  - ReplaceBytes:
      Offset:   -20
      FindH:    F3 EE 09 0A # vmov.f32 s1, #25.0
      ReplaceH: F0 EE 04 0A # vmov.f32 s1, #2.5
  # Replace QScreen::logicalDotsPerInchX() with our own multiplier of 16.0
  - ReplaceBytes:
      Offset:      26
      FindInstBLX: {SymPLT: "QScreen::logicalDotsPerInchX() const"}
      ReplaceH:    B3 EE 00 0B # vmov.f64 d0, #16.0

[shopma2]

Thanks David
I can't find the Use Kobo viewer for EPUB books checkbox. Is it in the Preferences, or in the Conversion settings?

And maybe I wasn't too clear in my first message, but I was not trying to convert my books to kepub (well, not anymore, after trying one to see what happens). I was only trying to continue as I have been doing for years, which is just sideloading a (nonDRM) book to the Kobo.

regards,
Hans

[kovidgoyal]

Connect your Kobo, then right click the kobo icon in calibre, then go to the uploads tab and deselect the Use kobo viewer option.

[foosion]

Originally Posted by theducks

Maybe
Depends on what you used (item on menu) it for.

Sometimes, but not always, when I upload multiple books to my Kobo, the cover to the book I'm currently reading vanishes and I'm left with a generic cover. I use Kobo Utilities to "Upload covers for selected books" to get the cover back.

I'm asking because it's a bit hard to test something that only happens sometimes. Using KU is slightly easier than re-uploading the current book.

EDIT: I also have different profiles set up for my two Kobo devices. The main difference is one updates Calibre to show which books are on device and the reading status and the other does not.

[theducks]

Those are good reasons.
I am puzzled about your cover loss as I have never seen that.
Do you have WiFi enabled? I don't and that may be your culprit. It 'updates' the book.

[Zapata]

Originally Posted by kovidgoyal

Connect your Kobo, then right click the kobo icon in calibre, then go to the uploads tab and deselect the Use kobo viewer option.

Greetings.

I just downloaded v8.0.1. I would like to disable the auto kepub conversion, but I can't see the "kobo icon" anywhere (my Clara HD is connected).

(P.S. this is my first post up here...)

[Sirtel]

Originally Posted by Zapata

Greetings.

I just downloaded v8.0.1. I would like to disable the auto kepub conversion, but I can't see the "kobo icon" anywhere (my Clara HD is connected).

(P.S. this is my first post up here...)

Does your computer see your Kobo?

[Zapata]

Originally Posted by Sirtel

Does your computer see your Kobo?

Yes it does. I can send books from calibre to the kobo but they are auto converted to kepub now. I actually prefer standard epubs.