Advanced typography controls for KOReader

[BrutalConfusion]

Hello. I have been using KOReader for quite some time now. While I do appreciate its customizability, I did find it somewhat lacking that I had no opportunity to customize font weights, slant types and text decorations (strikethrough, underline, etc) for each individual category: The font weight setting would affect all fonts globally; If a font has both italic and oblique variants, it would not distinguish between them; If you found underlines too thin, for example, you didn't really have any control over them.
I have made some modifications to crengine and now these settings can be controlled individually for each font category. I also turned the "main" font category to a category of its own. If a certain piece of text does not have any font category assigned to it, it will be controlled by "Unclassified" (main) category. All of the 9 categories can have their 4 attributes set independently from the rest — Font face, font weight, slant type, and text decoration weight.

Another important addition I have made is that the app will now recognize different widths of fonts as distinct entities. For example, instead of "Noto Serif", you will now get "Noto Serif", "Noto Serif Semi-Condensed", "Noto Serif Condensed", and "Noto Serif Extra-Condensed". This would apply to all font families based on their files' width metadata.

These changes can now be controlled by my plugin in Document settings. Essentially, the plugin gives you access to an advanced searchable font face selection screen (which can also be accessed normally), font weights, slant types, and text decoration weight (50–500%) for each category separately.

Another feature I have implemented is font caching: The app will not load all your fonts at startup: It will cache them once and only load those fonts if you actually select them. If you have even 1000s of font files, the app can launch almost instantly. The cache file barely takes 1 MB of space. This cache file will automatically update itself upon detecting any change to your font files.

All you need to do is patch crengine and use the "Advanced Typography" plugin.

I am really interested in your feedback, as I found it very surprising that almost no epub reader app would let the user such granular control.

You can find more about this here: https://github.com/Absolute-Confusion/Crengine-Extended

So far, a separate .appimage and .apk file are also provided if you wanna install it directly.

Let me know what you think

[Gormagon]

"I am really interested in your feedback, as I found it very surprising that almost no epub reader app would let the user such granular control."

I guess most people are just satisfied with what a reader app offers without the need to go to much into details.

I would have tried your plugin just for testing purposes, but then I read "Crengine-Extended has to be built into KOReader from source" and that's the point where I lost interest because I have no clue how to do this on Windows with "git clone --recursive https://github.com/koreader/koreader.git, then git checkout v2026.07.1 and git submodule update --init --recursive".

[JSWolf]

You should create a copies of KOReader (for the various platforms) for your git that has everything already built for testing. A lot of people won't know how to built your engine into KOReader.