Use the Inter font with slashed zeros (`zero` feature)

Use the Inter font with slashed zeros

Adopt Inter as the app's UI typeface.

Specifically, enable Inter's zero OpenType feature, which renders slashed zeros — this makes 0 unambiguous versus O, which matters a lot for reading callsigns, grid squares, and frequencies where the two are easily confused.

What to do

• Bundle the Inter font family with the app.
• Turn on the zero OpenType feature ("zero" / font-feature-settings: "zero" 1; or the platform equivalent) so all zeros are slashed.
• Apply it to the UI text styles used for callsigns, grids, frequencies, and other alphanumeric data where 0/O confusion is a problem.

Why

Slashed zeros remove 0/O ambiguity, which is especially valuable for amateur-radio data (callsigns, Maidenhead grids, frequencies).

References

• Inter: https://rsms.me/inter
• zero feature: https://rsms.me/inter/#features

Start by locating the app's UI text styles and bundled font assets, then check how the Java UI applies OpenType features. Done when Inter is bundled, the zero feature is enabled for callsigns, grids, frequencies, and other specified alphanumeric UI text, and those values render with slashed zeros.