🖼️ BMP Image Viewer

A simple BMP image viewer written in C using SDL2.
This project demonstrates how BMP files are structured and how pixel data can be read and displayed without relying on external image libraries.

👉 The main goal is educational – to help beginners understand the BMP file format and the process of rendering images pixel by pixel.

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🚀 Features

• Reads and displays 24-bit BMP images.
• Supports uncompressed BMP files (biCompression = 0).
• Command-line based – just provide the image file path as an argument.
• Uses SDL2 for rendering pixels on the screen.
• Helps in learning file I/O, BMP headers, and image rendering basics.

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📂 Project Structure

BMP_Image_Viewer/
│── src/            # Source code
│    └── bmp_viewer.c
│── pictures/       # Sample BMP images for testing
│── README.md       # Project documentation

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⚙️ Requirements

To build and run this project, you need:

• GCC (or any C compiler)
• SDL2 library

Install SDL2 (Linux example):

sudo apt update
sudo apt install libsdl2-dev

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🛠️ Build & Run

Compile the project:

gcc src/bmp_viewer.c -o src/bmp_viewer -lSDL2

Run the program with a BMP image:

src/bmp_viewer pictures/test_image.bmp

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🖼️ Example

Sample BMP images are provided inside the pictures/ folder.
Try:

src/bmp_viewer pictures/sample1.bmp

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📑 BMP File Structure (Simplified)

+----------------------+-----------------------------+
| Offset (Bytes)       | Field                       |
+----------------------+-----------------------------+
| 0 - 1                | Signature ("BM")            |
| 2 - 5                | File size                   |
| 6 - 9                | Reserved                    |
| 10 - 13              | Pixel data offset           |
+----------------------+-----------------------------+
| 14 - 17              | DIB header size             |
| 18 - 21              | Image width                 |
| 22 - 25              | Image height                |
| 26 - 27              | Color planes (always 1)     |
| 28 - 29              | Bits per pixel (24 in this) |
| 30 - 33              | Compression (0 = none)      |
| 34 - 37              | Image size (may be 0)       |
| ...                  | More header fields          |
+----------------------+-----------------------------+
| Pixel Array          | Actual pixel data (BGR)     |
+----------------------+-----------------------------+

👉 In this project, we only handle:

• 24-bit images (Bits per pixel = 24)
• Uncompressed data (Compression = 0)

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⚠️ Current Limitations

• Supports only 24-bit BMP images.
• Works only with uncompressed BMP files (biCompression = 0).
• No GUI features – runs from command line.

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🔮 Future Improvements

Planned features:

• Support for 32-bit BMP images.
• Support for different compression methods.
• Add image operations: rotate, crop, zoom.
• Cross-platform build scripts (Windows & Linux).

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📚 Learning Outcome

By studying this project, you will learn:

• How BMP headers are structured.
• How raw pixel data is stored in a file.
• How to use SDL2 for rendering images pixel by pixel.
• Basics of graphics programming in C.

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🤝 Contributing

Contributions are welcome!
You can:

• Fix bugs
• Add support for new BMP formats
• Improve documentation
• Suggest new features

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📜 License

This project is licensed under the MIT License – feel free to use and modify it.

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