PNG to JPEG Converter

A fast, modern C++17 PNG to JPEG converter with zero external dependencies.

Features

• Pure C++17 implementation
• No external libraries required (no libpng, libjpeg, etc.)
• Supports 8-bit PNG images (grayscale, RGB, RGBA)
• Adjustable JPEG quality (1-100)
• Cross-platform (Linux, macOS, Windows)

Building

Requirements

• CMake 3.10 or higher
• Only g++ tested

Compile

# Clone the repository
git clone https://github.com/molecula451/png2jpeg.git
cd png2jpeg

# Create build directory
mkdir build && cd build

# Configure and build
cmake ..
make

# (Optional) Install
sudo make install

Windows (Visual Studio)

mkdir build && cd build
cmake ..
cmake --build . --config Release

Usage

# Basic usage (output will be input.jpg)
./png2jpg input.png

# Specify output filename
./png2jpg input.png output.jpg

# Set JPEG quality (1-100, default: 85)
./png2jpg -q 90 input.png

# Verbose output
./png2jpg -v input.png output.jpg

# Show help
./png2jpg --help

# Show version
./png2jpg --version

Options

Option	Description
-q, --quality <1-100>	Set JPEG quality (default: 85)
-v, --verbose	Enable verbose output
-h, --help	Show help message
--version	Show version information

Examples

# Convert with default quality (85)
./png2jpg photo.png

# High quality conversion
./png2jpg -q 95 photo.png photo_hq.jpg

# Lower quality for smaller file size
./png2jpg --quality 60 --verbose screenshot.png compressed.jpg

Limitations

• Only supports 8-bit depth PNG images
• Interlaced PNGs are not supported
• Alpha channel is ignored during conversion

License

See LICENSE for details.