slide_puzzle

A slide (15) puzzle implemented in Dart and Flutter.

Live Demo: https://kevmoo.github.io/slide_puzzle/

Features

Multiple Themes:
- Simple: Minimalist numerical tiles with smooth physics animations.
- Seattle: Image-based slider dividing photography across the grid.
- Plaster: Stylized typographic display using custom font geometry.
Physics & Animations: Spring simulation, velocity decay, and directional drag physics.
Built-in Solver:
- Shortest-path A* solver utilizing Manhattan distances and linear conflicts.
- Step-by-step hint button and automated playback solve mode.
Auto-Play & Metrics: Automatic random move ticker with move and tile counters.

High-Performance Nibble Packing: Boards $\le 4 \times 4$ use _PuzzleSmart backed by a Uint32List packed into 4-bit nibbles for zero-allocation state transitions.
Incremental Delta Tracking: Tile movements calculate distance deltas and linear conflict adjustments incrementally without full board rescans.
Generic Fallback: Arbitrary board dimensions ($>16$ tiles, e.g. 5×5) gracefully fall back to _PuzzleSimple (Uint8List).

# Run locally in Chrome
flutter run -d chrome

# Run test suite
flutter test

# Run tests with coverage
flutter test --coverage