Jean-Luc Makiola
cf0540fce4
Write path: - realignRecurrence now handles weekly BYDAY only. What the rule must agree with is the series *anchor*, which moves by the same wall-clock shift as the dragged occurrence — weekday survives that (uniform mod 7), day-of-month does not. BYMONTHDAY=28 with a January anchor, occurrence Feb 28 dragged to Mar 1, produced a Jan 29 anchor under a BYMONTHDAY=1 rule: a DTSTART that is not an instance of its own rule. Also refuse when the shift is not a whole number of days, which would carry a late-enough anchor across an extra midnight. - The accepted parts are now a subset of parseSimpleRecurrence's, so anything realignable is a rule the UNTIL guard can actually read. FREQ=MONTHLY;BYDAY=MO previously slipped past it and could move a series past its own end. - The UNTIL check moved to write time and picks the date the chosen scope actually starts at: the anchor for a whole-series move, the occurrence for a split, nothing for a single occurrence. It used to test the occurrence in every case and refused the ordinary drag of a bounded series' last one. - shiftedByDays preserves the instant duration for timed events, as shiftedTo already did — a month drag onto a DST changeover rewrote the whole series' DURATION. - Guard against a second drop landing while one is in flight; the shifts would compound on the re-read anchor. Gestures: - A long press that never moved wrote a reschedule: the target snaps to the 15-minute grid at pickup, so an event at 09:07 resolved to 09:00 the instant it lifted. The drop is now refused when it lands on the slot it started from. - After pickup the gesture is driven and consumed on the initial pass. Pinching mid-drag used to zoom and drag at once, then write wherever the zoom left the block; the month grid's tap layer opened the day on lift. - RTL: pointer x was mapped to columns as if the grid were LTR, so a drop landed 6-n columns away, and both ghosts used the direction-aware offset with root coordinates, mirroring them across the screen. - The month drop passes the day delta instead of a date, so the grid and the view model no longer each resolve the event's first day in their own zone.
Calendula
A modern Material 3 Expressive calendar for Android.
Reads, writes, and reminds — on top of the system calendar, with zero network access.
Calendula is named after the flower whose name — like the word calendar —
comes from the Latin kalendae, the first day of the month. It lives
entirely on top of Android's CalendarContract: any calendar synced to your
device (CalDAV via DAVx5, Google, local, WebCal subscriptions, …) simply
appears, and everything you create or edit syncs back the same way. No own
database, no sync stack reinvented.
✨ Features
Calendar
- Month, week, and day views with a one-tap view switcher
- Full event details — attendees and their responses, reminders, recurrence (humanized), availability, visibility, foreign time zones
- Per-calendar visibility toggle, grouped by account
Editing
- Create, edit, and delete events — including recurring events with scoped writes: only this event, this and all following, or the whole series
- Recurrence picker with one-tap presets and custom rules (interval, weekday toggles, end conditions); rules it can't express are preserved verbatim
- Conflict-safe saves: if an event changed elsewhere while you were editing, Calendula asks instead of silently overwriting
- Read-only calendars (WebCal, birthdays) are detected and respected
Reminders
- Event reminders delivered by Calendula itself as notifications — essential when it's your only calendar app, since Android delegates reminder delivery to calendar apps
- Tap a reminder to land on the event
Design & privacy
- Real Material 3 Expressive throughout — dynamic color (Android 12+), expressive motion and shapes, light/dark theme
- English and German UI plus community translations (Spanish, French, Italian, Polish, and more in progress), per-app language setting — and open to more languages
- Zero telemetry, zero analytics, no internet permission — your data never leaves the device
📦 Install
Pick whichever channel you already use — they all install the same app:
| Channel | Updates | Notes |
|---|---|---|
| Official F-Droid | On F-Droid's build schedule | Recommended; no extra setup |
| Self-hosted F-Droid repo | Minutes after a release | Fastest; needs the repo added once |
| Codeberg release / Obtainium | Per release | Plain APK download, or automated by Obtainium |
| Google Play | — | Coming soon |
| Build from source | Whenever you build | Full control |
F-Droid (recommended)
Calendula is on the official F-Droid repository — just search for Calendula in any F-Droid client, or install it from f-droid.org.
F-Droid rebuilds from source on its own schedule, so a new version usually shows up there a few days after release.
Self-hosted F-Droid repo (fastest updates)
Every release is built, signed, and published to a self-hosted F-Droid repository as part of the release pipeline, so it lands there first. Add it once and your F-Droid client handles updates from then on:
-
In your F-Droid client, open Settings → Repositories → Add (or open the link below on your phone):
https://apps.dev.jeanlucmakiola.de/dev/fdroid/repo?fingerprint=C2C0640402BF458FC0ED957AF0B37AA4C14022E72F89CE90B5965B458CF73425Repo:
https://apps.dev.jeanlucmakiola.de/dev/fdroid/repo· fingerprint (SHA-256):C2C0 6404 02BF 458F C0ED 957A F0B3 7AA4 C140 22E7 2F89 CE90 B596 5B45 8CF7 3425 -
Refresh, search for Calendula, install.
Codeberg release / Obtainium
If you'd rather not use F-Droid at all, every release is also published on
Codeberg with the
signed APK (calendula_vX.Y.Z.apk) and a .sha256 checksum attached — download
and install it directly.
For automatic updates from that channel, use
Obtainium — on the phone,
add Calendula in one tap,
or do it by hand: Add App → paste https://codeberg.org/jlmakiola/calendula
→ Add. Either way, Obtainium tracks the releases and prompts you when a new
one appears.
Google Play (coming soon)
Calendula is on its way to Google Play as an additional channel. It isn't live yet — this section gets a link once it is. Play builds will be signed with Google's key rather than mine, so switching between Play and any other channel will require an uninstall.
Testers wanted. Play requires a round of closed testing before the app can go public, and I'm still looking for testers. If you'd like to help, email business@jeanlucmakiola.de with the Google account address you want to use — that address is what I need to add you to the closed test.
Build from source
The build is a plain Gradle build with no proprietary dependencies — see
docs/BUILDING.md (note the floret-kit submodule).
Official F-Droid, the self-hosted repo, and the Codeberg releases all share the same signing key, so you can switch freely between them without reinstalling.
📚 Documentation
- Contributing — how to report, propose, and patch
- Building from source — requirements and Gradle tasks
- Architecture — the layered design and key pipelines
- Milestones — what's shipped and what's next
🤝 Contributing
Bug reports, ideas, and patches are all welcome on Codeberg.
The short version: start with an issue. Features get a yes-or-no before they
get code, and both features and bugs are assigned a milestone whose
release/vX.Y.Z branch your pull request then targets. Typo and docs fixes can
skip straight to a pull request. Translations don't go through pull requests at
all — Weblate owns them.
Read CONTRIBUTING.md before writing code: it covers the
workflow, the build (note the floret-kit submodule), and the architectural
rules a change is reviewed against.
🌍 Translations
Calendula ships in English and German, with community translations in Arabic, Chinese, French, Italian, Polish, Portuguese, Russian, and Spanish at varying degrees of completeness — partial is fine, untranslated strings simply fall back to English. You're warmly invited to add or finish your language. Translations are managed on a self-hosted Weblate:
No coding needed — register on the Weblate server, pick (or request) a language, and translate the strings in your browser. You can also reach this link in the app from the top of Settings → App language.
📜 License
MIT — Jean-Luc Makiola, 2026