Question about converting Thai fonts to Papyrix-compatible .epdfont

[MiniKuma15]

Hi,
I have a question about custom fonts in Papyrix.
I found this online converter: https://epdfont.clev.app/
It generates .epdfont files, but when I copy the generated font to my device, Papyrix does not recognize or display them.
I also downloaded one of the English sample fonts for Papyrix, and it works correctly. Because of that, I think the .epdfont files generated by the website are not compatible with Papyrix.
I know there is already a documented way to convert fonts for Papyrix, but unfortunately I don't have a computer, so I can't follow the conversion process or build the required tools.
I would like to use a custom Thai font, but I don't know how to convert a TrueType/OpenType font into a Papyrix-compatible .epdfont without a PC.
Could you please tell me:
Is the .epdfont generated by https://epdfont.clev.app/ compatible with Papyrix?
If not, what is different about its format?
Is there any way to convert a Thai TrueType/OpenType font into a Papyrix-compatible .epdfont without using a PC?
If not, would it be possible to provide an easier conversion method, such as an online converter, in the future?
Thank you for your time.

[pliashkov-spm]

Hi @MiniKuma15, thanks for the detailed question!

Short answer

The .epdfont files from https://epdfont.clev.app/ are not compatible with Papyrix — it's an unrelated third-party tool that generates a different format. Papyrix uses its own binary layout with 2-bit grayscale bitmaps optimized for e-paper, so files from that site won't be recognized.

Good news: Thai works out of the box

The built-in fonts already include full Thai script support — no custom font needed. Thai text in your EPUB/FB2/TXT books should render correctly with the default font. Just open your Thai book and it should work.

If you want a different Thai typeface

This requires converting the font with fontconvert.py from this repo, which does need a computer (any OS — Linux, macOS, or Windows with WSL). Here's a quick guide in case you get access to one or can ask a friend:

1. Install uv (one command):

curl -LsSf https://astral.sh/uv/install.sh | sh

2. Clone the repo:

git clone https://github.com/bigbag/papyrix-reader.git
cd papyrix-reader

3. Convert your Thai font (e.g. Noto Sans Thai):

# Download the font from Google Fonts, then:
uv run scripts/fontconvert.py my-thai-font \
    -r NotoSansThai-Regular.ttf \
    -b NotoSansThai-Bold.ttf \
    --2bit --thai --all-sizes \
    -o /tmp/fonts/

This creates three folders: my-thai-font-14/, my-thai-font-16/, my-thai-font-18/, each containing regular.epdfont and bold.epdfont.

4. Copy to SD card:

SD card:
  /config/fonts/my-thai-font-14/regular.epdfont
  /config/fonts/my-thai-font-14/bold.epdfont
  /config/fonts/my-thai-font-16/...
  /config/fonts/my-thai-font-18/...

5. Create a theme file (/config/themes/thai.theme):

[theme]
name = Thai Custom Font

[fonts]
reader_font_small = my-thai-font-14
reader_font_medium = my-thai-font-16
reader_font_large = my-thai-font-18

6. Restart the device → Settings > Reader > Theme → select your theme.

Docs

• Custom Fonts guide — full conversion instructions, options, and examples
• Fonts overview — supported scripts, font samples, and CJK setup

About an online converter

There's no online converter for Papyrix at the moment. It's something we could consider in the future, but for now the fontconvert.py script is the only way to generate compatible .epdfont files. If you share which Thai font you'd like to use, I can convert it for you and attach the files here.

[MiniKuma15]

@pliashkov-spm
Thank you so much! I still don't have access to a computer right now. Could you please help convert this font for me?
​Here is the font link for Sarabun :
https://fonts.google.com/specimen/Sarabun
​I really appreciate your help!