Kobalt: an alternative reader app for Kobo devices

[JSWolf]

Originally Posted by Uncle Robin

YES - make bloaty options like line height adjustments optional plugins, great idea!

Line height is an option that needs to be built-in. Thinks like ignoring pages from the book for the page numbering is a bloaty option.

[JSWolf]

@MrSilverstrike what requested features do you feel should not be implemented?

[JSWolf]

Is it possible to switch from ePub or KePub to Kobalt and keep all highlights/bookmarks?

[howyoudoin]

On the Libra 2, would page turn animations drain the battery quicker or similar compared to fully refreshing every page?

[MrSilverstrike]

Originally Posted by JSWolf

@MrSilverstrike what requested features do you feel should not be implemented?

That's a good question since I don't maintain a list of items I've dismissed. So far, this is my list of what I'm not doing:

• Support for opening Kobo DRM-protected books (technically possible, legally questionable, so Kobalt only opens DRM-free content)
• A plugin system (technically challenging + it becomes a pain with compatibility since I have to be rigid about what APIs I expose)
• A text contrast adjustment setting (weight slider is sufficient)
• Separate CFA adjustments in Kobalt (it should follow the system setting)
• Automatic end matter detection and exclusion for page numbers (technically unfeasible; manual option is still worth investigating but probably not worth the added complexity)
• ADE page numbering, or any sort of page numbering system that isn't just counting how many screens are left in the book

These are effectively product decisions and not up for debate.

As a rule: if an addition could introduce potential confusion (e.g. how would a contrast adjustment benefit Kobalt vs the included weight slider?) then I'm sticking with what works and I'm not changing my mind.

Page numbering is another one such item. Having multiple ways to count pages is just confusing to most regular people. Remember, we're on a very niche forum here.

Also, given the positioning of Kobalt as being somewhere in between the stock reader and KOReader... if power users feel like they're missing stuff, I think KOReader is a better fit for those people.

I will happily read through people's suggestions, though. Sometimes people will suggest things I'll reject but come up with a better solution for. The bookmark pins are one such example. Someone requested a "map button" and that became bookmarks you can pin for easy navigation with a shortcut tray which doesn't exist in any e-reader I know of, but is a really nice-to-have feature.

Originally Posted by JSWolf

Is it possible to switch from ePub or KePub to Kobalt and keep all highlights/bookmarks?

Not at this time, no. They're separate today, and still accessible via Nickel's built-in reader if you need previous ones. It's something I plan on looking into later so they can be shared.

[MrSilverstrike]

Originally Posted by howyoudoin

On the Libra 2, would page turn animations drain the battery quicker or similar compared to fully refreshing every page?

From what I tested, the impact is essentially negligible.

Backlight, CPU utilization etc is all much more impactful for actual battery life.

Nickel in 4.x has a bug with WiFi where it says on for 15 minutes even if Bluetooth is disabled and that one has a much bigger battery impact than this, for example. (Also a bug I plan on fixing with Kobalt, btw.) Normally WiFi is supposed to deactivate after 2 minutes.

[howyoudoin]

Originally Posted by MrSilverstrike

From what I tested, the impact is essentially negligible.

Backlight, CPU utilization etc is all much more impactful for actual battery life.

Nickel in 4.x has a bug with WiFi where it says on for 15 minutes even if Bluetooth is disabled and that one has a much bigger battery impact than this, for example. (Also a bug I plan on fixing with Kobalt, btw.) Normally WiFi is supposed to deactivate after 2 minutes.

Thank you

[rantanplan]

What I realized is that sync.crosspointreader.com can merge multiple md5s of the same book. Everyone struggling with the problem of that, you should look into that specific kosync server.

IMHO this is something that more sync servers should tacle.

[JSWolf]

Does Kobalt use less battery then KOReader?

[rantanplan]

Originally Posted by JSWolf

Does Kobalt use less battery then KOReader?

I wonder if that even matters. Like, if your device lasts 20 hours or 18 hours?

[MrSilverstrike]

Originally Posted by JSWolf

Does Kobalt use less battery then KOReader?

Yes, because it uses standby mode if you're not turning pages. That can be enabled inside of KOReader, but it's disabled by default there, which means in general you get better battery life compared to stock KOReader.

Kobalt's also more efficient than the built-in reader app in general.

Originally Posted by rantanplan

What I realized is that sync.crosspointreader.com can merge multiple md5s of the same book. Everyone struggling with the problem of that, you should look into that specific kosync server.

IMHO this is something that more sync servers should tacle.

Looking into this later!

[rantanplan]

Originally Posted by MrSilverstrike

Looking into this later!

Now I feel awkward, I didn't mean this as a todo for you

[MrSilverstrike]

Originally Posted by rantanplan

Now I feel awkward, I didn't mean this as a todo for you

No worries. I don't mean I'm looking into this right now haha

[jackie_w]

Originally Posted by MrSilverstrike

You'll be happy to know that the list of features I wanted to implement is almost finished, and I really dislike feature creep, so I think you'll like what I still have in store for Kobalt.

Either way, I just released beta 6, so give it a shot and let me know what you think. You can find the release notes here.

Thanks for this latest release. It already does everything I need but pleasant surprises are always welcome! I've completely moved away from kepubs and back to plain epubs now.

I didn't realise I wanted/needed 'vertical page spacing' until I saw it. Is this unique to Kobalt?

I do have a couple of questions:

1. Image viewer. What is the definition of a "large image" which determines whether a long-press opens the image in the viewer, or not? Is there a reason why *all* images aren't allowed to open the viewer?

2. Default global font. Please can you explain the difference between 'Default global font' and 'Serif typeface' in the 'Fallback Fonts' section? Where/when is the former used?

[MrSilverstrike]

Originally Posted by jackie_w

Thanks for this latest release. It already does everything I need but pleasant surprises are always welcome! I've completely moved away from kepubs and back to plain epubs now.

I didn't realise I wanted/needed 'vertical page spacing' until I saw it. Is this unique to Kobalt?

I do have a couple of questions:

1. Image viewer. What is the definition of a "large image" which determines whether a long-press opens the image in the viewer, or not? Is there a reason why *all* images aren't allowed to open the viewer?

2. Default global font. Please can you explain the difference between 'Default global font' and 'Serif typeface' in the 'Fallback Fonts' section? Where/when is the former used?

Vertical space paging is something that as far as I know, is only available here, yes!

As for your questions:

1. It checks the image’s displayed size on the page. The image must cover at least 5% of the page area, and both dimensions must be at least 8% of the page’s shorter side. The restriction keeps small ornaments and narrow wordmarks from taking over normal reading gestures.

2. The serif typeface is used when you select Publisher Fonts and you supply a book without embedded fonts that's marked as `font-family: serif` in the CSS.