# Fonts

The theme's default font (`themes/main_theme.tres`) is `OpenSans-SemiBold.woff2`, the
font Godot uses when a project sets none, saved from Godot so the game looks the same.
Text it has no letters for, such as Japanese, falls back to `NotoSansJP-Medium.otf`.

Both are under the SIL Open Font License, see `OpenSans-LICENSE.txt` and
`NotoSansJP-LICENSE.txt`.

`NotoSansJP-Medium.otf` is the Medium weight from
[noto-cjk](https://github.com/notofonts/noto-cjk/tree/main/Sans/SubsetOTF/JP), changed in
one way: its line metrics (`hhea` ascent and descent) are set to Open Sans's. Godot makes
every line as tall as the tallest font in the fallback chain, so with Noto's own, taller
metrics all text in the game would move down and rows would grow, even without any
Japanese on screen. The glyphs are unchanged. To update the font, download it again and
set the metrics with [fontTools](https://github.com/fonttools/fonttools):

```python
from fontTools.ttLib import TTFont

reference = TTFont("OpenSans-SemiBold.woff2")  # needs the brotli package
noto = TTFont("NotoSansJP-Medium.otf")
scale = noto["head"].unitsPerEm / reference["head"].unitsPerEm
noto["hhea"].ascent = round(reference["hhea"].ascent * scale)
noto["hhea"].descent = round(reference["hhea"].descent * scale)
noto["hhea"].lineGap = 0
noto.save("NotoSansJP-Medium.otf")
```

`tests/integration/test_theme.gd` checks that Japanese has a font and that the line
height is still Godot's.