slide_puzzle

September 13, 2026 · View on GitHub

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

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

Slide Puzzle Screenshot

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.

Architecture

  • High-Performance Nibble Packing: Boards ≤4×4\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>16 tiles, e.g. 5×5) gracefully fall back to _PuzzleSimple (Uint8List).

Development

# Run locally in Chrome
flutter run -d chrome

# Run test suite
flutter test

# Run tests with coverage
flutter test --coverage