Picture Puzzle

A desktop sliding puzzle game similar to the standard widget in Windows 7. Written in modern C++17 with FLTK for the graphical interface, it provides a lightweight, cross-platform experience with fast compilation and responsive UI.

The goal is simple: rearrange the tiles to restore the original image, moving one piece at a time.

Features

Image Handling

Upload an image in any format and resolution — the program will:
- Resize it to fit the puzzle grid (300x300).
- Slice it into 3x3 tiles.
- Save tiles into a dedicated resources/ subdirectory.
Uses stb_image, stb_image_resize, and stb_image_write for image loading, resizing, and saving.

Built-in Embedded Image

Both Linux and Windows builds include a fully embedded image (Toucan) directly inside the executable.
The embedded image is stored in resources.o as a static byte array.
A C-language image converter tool is included, which:
- Takes a PNG image.
- Generates a resources.cpp file containing the image bytes.
This allows shipping the game as a single executable without requiring external image files.
The embedded Toucan image serves as the default puzzle; users can still load their own images.

Puzzle Gameplay

Standard 3×3 sliding puzzle with one empty tile.
Random shuffling with solvability check to ensure the puzzle can be completed.
Option to load:
- Built-in embedded image.
- External images from resources/ folder or user upload.

Automatic Puzzle Solver

A* search algorithm implementation.
Uses Manhattan distance as the heuristic (g(n) + W(n)).
Shows a step-by-step animation of the optimal solution.

Cross-Platform

Works on Linux and Windows.
On both platforms, distributed as a single executable with embedded resources.

Technologies Used

C++17 STL — std::unique_ptr, std::shared_ptr, priority_queue, unordered_set, filesystem, algorithm.
FLTK — lightweight GUI library.
stb_image / stb_image_resize / stb_image_write — image processing.
A* algorithm for optimal pathfinding.
Custom hashing and equality comparison for puzzle states.
Custom C-based resource generator for embedding binary image data into the executable.

Building

Linux

Install FLTK development package:

sudo apt install fltk1.3-dev
git clone https://git.scratko.xyz/picture-puzzle
cd picture-puzzle
make
./main

For Windows platform

Requires FLTK for Windows.
Prebuilt x86_64 executable available here:
Download Windows version