Mermaid Diagram Converter

A Python utility that converts Mermaid diagram files to high-resolution PNG images with optimized settings and transparent backgrounds.

Features

• Batch conversion of .mmd files to PNG format
• High-resolution output with customizable scaling
• Transparent background support
• Optimized diagram settings for better readability
• Configurable font sizes and spacing
• Error handling and detailed logging

Prerequisites

• Python 3.6 or higher
• Node.js and npm installed

Installation

1. Clone this repository:

git clone https://github.com/doomL/mermaid-bulk-converter
cd mermaid-bulk-converter

2. Install Python dependencies:

pip install pathlib

3. Install Mermaid CLI:

Method 1: Local Installation (Recommended)

npm install -g @mermaid-js/mermaid-cli

Usage

Run the script from the command line:

python mermaid-bulk-converter.py -i /path/to/input/directory -o /path/to/output/directory -s 3.0

Arguments

• -i, --input: Directory containing Mermaid (.mmd) files
• -o, --output: Directory where PNG files will be saved
• -s, --scale: Scale factor for PNG resolution (default: 3.0)

Example

1. Create a Mermaid diagram file flowchart.mmd:

graph TD
    A[Start] --> B{Decision}
    B -->|Yes| C[OK]
    B -->|No| D[Cancel]

Loading

2. Convert to PNG:

python mermaid-bulk-converter.py -i ./diagrams -o ./output -s 4.0

Configuration

The script uses optimized default settings for:

• Font size and family
• Diagram padding and spacing
• Node layout and dimensions
• Background transparency
• Device scale factor

These settings can be modified in the config dictionary within the script.

Error Handling

The script includes comprehensive error handling:

• Creates missing output directories
• Reports conversion errors for individual files
• Cleans up temporary files
• Provides detailed error messages

License

MIT License

Contributing

1. Fork the repository
2. Create a feature branch
3. Commit your changes
4. Push to the branch
5. Create a Pull Request