CALCULATOR — round-screen calculator for Xiaomi Watch S4
A calculator laid out for the circular display: tapered key rows that follow the chord of the round screen, large touch targets, high-contrast keys (#3a3a3e on #000). Supports chained operations, percent, sign toggle, decimals, and divide-by-zero error recovery.
Status: WORKING ON WATCH (user-confirmed through v1.2; layout improved through 1.6).
Usage
- Tap keys to compute;
ACclears all %divides the display by 100 (plain semantics — 200+10% = 200.1)- Back button exits (no onBackPress interception — intercepted back made the button feel dead on a single-page app)
- Crown does nothing (unsupported API on Vela); the original crown-selection scheme was abandoned for a directly-tappable list layout
Round-screen layout (the interesting part)
- Short viewport (~300px) so rows never exceed the circle chord
- NO vertical margins on list-items (spacing baked into height — CSS/JS drift bug)
- Top/bottom spacer items so first/last keys can center in the viewport
- Focus = round((scrollY + KEYS_H/2 − ITEM_H/2 − PAD)/ITEM_H); re-centered after every press via scrollTo
- Geometry + contrast assertions live in
tests/visual.cjs(parses the .ux)
Project layout
src/
├── app.ux, manifest.json # com.example.hellovela identity (preserved for updates)
├── common/icon.png # 192×192 circular icon
└── pages/index/index.ux # keys list + display + state machine
tests/
├── page.cjs # state machine: driven via press(key) sequences
└── visual.cjs # parsed-from-source geometry/contrast contracts
Build & test
npm ci
npm run release
node tests/page.cjs
node tests/visual.cjs
Install
Side-load via AstroBox. Releases: https://gitea.oimcloud.myaddr.tools/codex-bot/vela-calculator
Bug history worth knowing (all caught by the stale-test TDD pass)
freshnever initialized → first digit appended to '0' ('01')=with no pending op zeroed the display- Operators didn't auto-evaluate pending ops (2+3×4 gave 12, not 20)
- Repeated
=didn't re-apply the last op (2+3== gave 5, not 11)