Jatra (जात्रा)

A living almanac of the great Newar festivals of the Kathmandu Valley: Indra Jatra, Mha Puja, Yomari Punhi, Bisket Jatra, Rato Machhindranath, and Sithi Nakha. Each one gets its story, its rituals, a countdown, and a hand-painted scene that never stops breathing.

Everything that moves in this app is drawn with CustomPainter and driven by an AnimationController. There is no animation package, no Lottie, no Rive. That is the point of the repo.

What to look at

• The mandala (lib/painters/mandala.dart, driven in lib/screens/home.dart): an eightfold mandala in a pinned SliverPersistentHeader. It idles at one turn per ninety seconds, tracks a finger by atan2 deltas with wraparound normalization, and when flung it coasts on a real FrictionSimulation, with angular velocity derived from the tangential component of the gesture velocity. Drag it. Fling it. That is the interview demo.
• The scenes (lib/painters/scenes.dart): every festival has a flat-color scene that loops on a single phase, so nothing jumps at the wrap. The Machhindranath chariot sways as its wheels roll, the Bisket pole rocks between a taut rope and a slack one, the Lakhey bobs with a mane that shivers petal by petal, three Mha Puja flames each keep their own time, steam rises off a yomari under a December moon, and a hiti spout beads water into widening ripples.
• The choreography: staggered Interval curves for card and section entrances, Hero glyphs across a custom PageRouteBuilder transition, a countdown arc animated with TweenAnimationBuilder, and RepaintBoundary around every looping painter so the text layers never pay for the animation.

The design

The palette is a jatra at dusk: soot, sindoor vermilion, marigold, rice-flour cream. Flat color only, no gradients. Yatra One carries the display type in Latin and Devanagari alike; countdowns are set in Devanagari numerals.

Festival dates follow the lunar calendars of the valley, so the Gregorian dates in lib/data/festivals.dart are close approximations for the coming cycle, clearly labeled as such in the app.

Run it

flutter pub get
flutter run       # a device with 120Hz does it justice
flutter test      # almanac, navigation, and calendar arithmetic

Preview