Touch How can I change system font?

[AlexViean]

Hi! I'm looking for a replacement of system font. I use English-Vietnamese dictionary and some Vietnamese eBook have table of contents in Vietnamese. So that I have got funny or lossy characters. My firmware version is 3.17.3 Please help!
Thank you very much!

[oren64]

See post#20 https://www.mobileread.com/forums/sho...=260100&page=2
"you can make up your own keypad just by replacing the letters in one of these patches"

EDIT: I had the same problem with my Hebrew dictionary, I add Hebrew keyboard to fix it.

[AlexViean]

Originally Posted by oren64

See post#20 https://www.mobileread.com/forums/sho...=260100&page=2
"you can make up your own keypad just by replacing the letters in one of these patches"

EDIT: I had the same problem with my Hebrew dictionary, I add Hebrew keyboard to fix it.

Thank you for replying. But this isn't what i need

[GeoffR]

There are a lot of things I don't understand about how fonts work, I hope someone else who has worked out these problems with another languages might be able to share some insights that might apply to Vietnamese too.

The fonts needed to display languages that are not supported by the interface, such as Arabic and Hebrew, are not loaded when the device first boots, only later when opening a book or when opening the font menu in an ePub book. Once that has happened, the glyphs that were missing from the boot fonts can be substituted with glyphs from the newly loaded fonts. I thought the same would apply to all languages, but perhaps that is not the case.

There is a problem with text that appears in italics in the interface (such as book titles) because it seems the mechanism for substituting slyphs from other fonts can't substitute a normal glyph if there is no italic version available, and I guess some languages don't use italics.

Some things to check:

* Have you sideloaded a font with all the Vietnamese glyphs you neeed? Fonts embedded in the book won't be available for use by the rest of the system.

* Have you opened the font menu in the book? That might be necessary to make the other fonts avaialble to the system when reading ePubs, although for KePubs it seems to be enough just to open the book.

It could be that the firmware only checks the built-in fonts and not sideloaded fonts when looking for the glyphs that it needs to substitute for missing glyphs. If that is the case then there might not be any solution to your problem, because I don't think anyone has worked out how to modify or replace the built-in fonts, which are all encrypted.

Here is a post that shows the Latin Extended Additional glyphs available in the Kobo Nickel font, which I think is the only built-in font that has any of those glyphs. If you have sideloaded a font with all the glyphs but are still missing the same glyphs that are missing in Kobo Nickel, then that probably indicates that only the built-in fonts are being used to substitute missing glyphs.

There is a list of 11 'priviledged' fonts: Amasis, Avenir Next Medium, Caecilia, Delima, Felbridge, Georgia, Gill Sans, Kobo Nickel, Malabar, Rockwell, Times New Roman. The ones in bold are not supplied with the current firmware, but were in earlier firmware versions. They are still treated as priviledged in that the advanced font menu will work (without any patches needed) if you have a sideloaded font with one of those names. It might be worth trying to rename a font with all the Vietnamese glyphs you need to one of those names and see if that causes it to be considered as a source of substitute glyphs.

Edit: From discussion in the Summary of modified fonts thread it appears that the interface and KePub reader are selecting fonts based on their PANOSE information. So something else to consider is the possibility that substitutes for missing glyphs might only be sourced from fonts with a compatible PANOSE profile.

[NiLuJe]

I can confirm the PANOSE stuff. If font styling is borked in the KePub reader (i.e., everything rendering as bold, italic, or missing bold, italics, that kind of thing), making the panose metadata sane fixes things.

[sherman]

Originally Posted by NiLuJe

I can confirm the PANOSE stuff. If font styling is borked in the KePub reader (i.e., everything rendering as bold, italic, or missing bold, italics, that kind of thing), making the panose metadata sane fixes things.

Or simply removing the information seems to work as well, as I have found.

[NiLuJe]

@sherman: I hadn't tried that, that's good to know, thanks .

[sherman]

Originally Posted by NiLuJe

@sherman: I hadn't tried that, that's good to know, thanks .

I only discovered the whole PANOSE thing a few days ago, and I wrote my discoveries on the other thread (modified fonts one).

I honestly don't know which part of the PANOSE information causes issues, as a font I was having problems with SEEMED to have valid PANOSE information set, yet my Kobo did not like it at all.

[AlexViean]

Thank you very much for replying particularly. I think I have to accept this awful truth

Some things to check:

* Have you sideloaded a font with all the Vietnamese glyphs you need? Fonts embedded in the book won't be available for use by the rest of the system.

* Have you opened the font menu in the book? That might be necessary to make the other fonts avaiable to the system when reading ePubs, although for KePubs it seems to be enough just to open the book.

I have done all and nothing seems have changed.
What should I do next?

[AlexViean]

Originally Posted by GeoffR

There is a list of 11 'priviledged' fonts: Amasis, Avenir Next Medium, Caecilia, Delima, Felbridge, Georgia, Gill Sans, Kobo Nickel, Malabar, Rockwell, Times New Roman. The ones in bold are not supplied with the current firmware, but were in earlier firmware versions. They are still treated as priviledged in that the advanced font menu will work (without any patches needed) if you have a sideloaded font with one of those names. It might be worth trying to rename a font with all the Vietnamese glyphs you need to one of those names and see if that causes it to be considered as a source of substitute glyphs.

I've found out that Kobo Nickel font can display all Vietnamese characters. I changed the name of Arial font to Rockwell. It works very well with ebook. But still, both dictionary and table of contents lost those characters.

[GeoffR]

Originally Posted by AlexViean

I've found out that Kobo Nickel font can display all Vietnamese characters. I changed the name of Arial font to Rockwell. It works very well with ebook. But still, both dictionary and table of contents lost those characters.

Well that must mean not all of the built-in fonts are used as sources of substitute glyphs. There are four fonts that seem to be treated differently than the others: Georgia, Avenir, Gothic, and Ryumin. It might only be Gothic that is used for substitutions.

In that case there is probably nothing you can do without patching the firmware. While it is possible that a patch could be made to change the font-family used in each place that could contain Vietnamese text, that is likely to be a big job and would have to be redone each time the firmware is updated. I can't personally commit the time needed to do this though, I think it would just be too much work unless there is a way to automate the process.

The only other way I can think of would be to find a way to bypass the encryption on the system fonts. That would open up a lot of possibilities and make many things easier if it could be done, but I don't know where to start with that.

[AlexViean]

Originally Posted by GeoffR

Well that must mean not all of the built-in fonts are used as sources of substitute glyphs. There are four fonts that seem to be treated differently than the others: Georgia, Avenir, Gothic, and Ryumin. It might only be Gothic that is used for substitutions.

In that case there is probably nothing you can do without patching the firmware. While it is possible that a patch could be made to change the font-family used in each place that could contain Vietnamese text, that is likely to be a big job and would have to be redone each time the firmware is updated. I can't personally commit the time needed to do this though, I think it would just be too much work unless there is a way to automate the process.

The only other way I can think of would be to find a way to bypass the encryption on the system fonts. That would open up a lot of possibilities and make many things easier if it could be done, but I don't know where to start with that.

I think that font could be Georgia. I tried to sideload customized Georgia (Arial renamed) but it didn't work, the system still uses built-in Georgia font.

[astroner]

https://tinhte.vn/threads/kobo-aura-...#post-49820025