Kobo system cannot recognize fonts added into system-wide fonts directory?

[codychan]

From Another thread:

https://www.mobileread.com/forums/sh...1&postcount=88

if you are really curious why I want to add fonts into system-wide directory why not just sideload those fonts, please check the context of that thread.

Using patch system, I successfully deleted several fonts in kobo system-wide fonts directory(/usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/), and they are no longer in the drop-list of changing-font in reading page.

But when I tried to add fonts into kobo system-wide fonts directory, the fonts I added are not in the drop-list(BTW, the fonts I added are working fine when sideloaded), so I did a little trick, add the following line to the end of the shell script which removes the fonts to list all fonts in /usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/ and print the list into `nickel home` directory:

ls usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/* > /mnt/onboard/fonts-list

So I check the list in fonts-list when I connect my Kobo to PC. And the fonts I added are exactly all in the list(as expected, the fonts I deleted are not in the list). It means I did add them into usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/ but Kobo cannot recognize them when I want to change fonts when I'm reading. Why is that?

And I notice another thing, when I extract the kobo firmware zip file and try to open *ANY* font in the kobo-update-4.11.12019\KoboRoot\usr\local\Trolltech\QtEmbedded-4.6.2-arm\lib\fonts, it failed to open it.

Double left-clicking it in Windows10, it says

"The requested file xxx is not a valid font file."

And I tried to open it using FontForge, it failed to open it too, it says:

"xxx is not a known format (or uses features of that format fontforge does not support, or is so badly corrupted as to be unreadable)."

That is so weird.

[NiLuJe]

@codychan: That's perfectly normal: the system fonts are encrypted and/or obfuscated.

[pazos]

Nickel probably uses a defined list of fonts at buildtime and register them with http://doc.qt.io/archives/qt-4.8/qfo...pplicationFont. For sideload content they scan a given directory with http://doc.qt.io/archives/qt-4.8/qdiriterator.html and try to load as many (valid) ttf/otf fonts as present in that folder.

So adding new fonts to the same folder won't work as expected.

[codychan]

Originally Posted by pazos

Nickel probably uses a defined list of fonts at buildtime and register them with http://doc.qt.io/archives/qt-4.8/qfo...pplicationFont. For sideload content they scan a given directory with http://doc.qt.io/archives/qt-4.8/qdiriterator.html and try to load as many (valid) ttf/otf fonts as present in that folder.

So adding new fonts to the same folder won't work as expected.

I guess I couldn't do anything about it then.

[NiLuJe]

Sidenote: current FW have moved to Qt 5.2 (or so, the relevant part is Qt5 here ;p), but this should still hold true, even if in spirit only .

[codychan]

Originally Posted by NiLuJe

@codychan: That's perfectly normal: the system fonts are encrypted and/or obfuscated.

Hi, do you know what fonts in the system-wide fonts directory can be deleted safely, the whole fonts list is:

usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/Amasis*
usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/Avenir*
usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/Caecilia*
usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/georgia*
usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/GillSans*
usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/KBJ*
usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/KoboNickel*
usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/Malabar*
usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/OpenDyslexic*

@jcn363 said in other thread that the georgia* and Avenir* are system fonts and do not remove them, but it seems kobo system are not using them as system fonts. Anyway, I just want to know what fonts can be deleted safely so the kobo system won't be affected.

[jcn363]

Originally Posted by pazos

Nickel probably uses a defined list of fonts at buildtime and register them with http://doc.qt.io/archives/qt-4.8/qfo...pplicationFont. For sideload content they scan a given directory with http://doc.qt.io/archives/qt-4.8/qdiriterator.html and try to load as many (valid) ttf/otf fonts as present in that folder.

So adding new fonts to the same folder won't work as expected.

Originally Posted by NiLuJe

Sidenote: current FW have moved to Qt 5.2 (or so, the relevant part is Qt5 here ;p), but this should still hold true, even if in spirit only .

Then, the process should be: make a fake program with Qt5.2 and desired fonts inside, take the hard coded fonts, rename with kobo's one name and exchange.
Isn't it?
Good luck.

[NiLuJe]

@codychan: No idea, no.

@jcn363: Err, what?

[jcn363]

Originally Posted by NiLuJe

@jcn363: Err, what?

If i understood correctly, to be able to exchange a system font, first we must have a hardcoded one in the same way and this is made by Qt (5.2) at compile time.
Good luck.

[NiLuJe]

I think the obfuscation is Kobo-specific, not Qt-specific .

[tshering]

Originally Posted by codychan

Hi, do you know what fonts in the system-wide fonts directory can be deleted safely, the whole fonts list is:

usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/Amasis*
usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/Avenir*
usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/Caecilia*
usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/georgia*
usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/GillSans*
usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/KBJ*
usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/KoboNickel*
usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/Malabar*
usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/OpenDyslexic*

@jcn363 said in other thread that the georgia* and Avenir* are system fonts and do not remove them, but it seems kobo system are not using them as system fonts. Anyway, I just want to know what fonts can be deleted safely so the kobo system won't be affected.

According to this post, it is sufficient when you keep KBJ-TsukuMinPr6N-RB.ttf. Be aware that this information is not necessarily valid for the more recent firmwares.
When you put your device to sleep, as most people seem to do, instead of powering it off, you only have to open a book once, and the GUI will use your custom fonts from that point onwards (until you power the device off).

[jcn363]

Originally Posted by tshering

According to this post, it is sufficient when you keep KBJ-TsukuMinPr6N-RB.ttf. Be aware that this information is not necessarily valid for the more recent firmwares.
When you put your device to sleep, as most people seem to do, instead of powering it off, you only have to open a book once, and the GUI will use your custom fonts from that point onwards (until you power the device off).

I can confirm that's true for last version (4.11.12019) too.

Good luck.