A* Pathfinding Visualizer in Rust

An interactive grid-based visualizer for the A* (A-star) pathfinding algorithm. You can draw walls, set the start and goal positions, and watch the algorithm step through the grid to find the shortest path — or indicate when no path is possible.

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Features

• Interactive grid editor
• Wall placement via mouse clicks
• Start and Goal selection
• Visualized search (Visited nodes)
• Shortest path traced in real-time
• Reset the board after path is drawn
• Graceful handling when no path exists

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Controls

Key / Mouse	Action
W	Switch to Wall placement mode
S	Switch to Start placement mode
G	Switch to Goal placement mode
Mouse Left Click	Place/remove depending on mode
Space	Run A* algorithm
R	Reset board (clears path/visited)
Esc / X	Close the window

Start and Goal must be set before pressing Space.

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Project Structure

src/
├── main.rs         # Application entry point, handles events
├── astar.rs        # A* algorithm logic with step-by-step rendering
├── grid.rs         # Drawing logic and pixel-level cell rendering
└── types.rs        # CellType, PlacementMode, and Cell definition

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How It Works

1. Grid Initialization: A 2D vector of Cell, each with a type.

2. User Interaction: Mouse clicks and keypresses update the grid.

3. A* Algorithm:

   • Uses a binary heap (min-heap with Reverse wrapper).
   • Calculates heuristic (Manhattan distance).
   • Tracks visited nodes and reconstructs the shortest path.

4. Rendering:

   • The grid is redrawn on every significant state change.
   • Colors reflect cell state (wall, visited, path, etc.).