BKChem (Python 3 Modernized)

BKChem is a free (open source) 2D molecular drawing program. It was originally developed by Beda Kosata and has been a staple in the open-source chemical informatics community for years.

This repository contains a modernized version of BKChem, fully ported to Python 3.10+ and stabilized for modern operating systems.

Key Features

• Intuitive Drawing: Easy creation of bonds, atoms, and complex molecular structures.
• Rich Export Formats:
  • Vector: SVG, PDF (via Cairo and Piddle), PostScript, EPS.
  • Document: OpenOffice/LibreOffice Draw (ODF), LaTeX.
  • Image: PNG (via Cairo).
• Chemical Intelligence: Correct handling of atom properties, isotopes, and structure validation.
• Scalability: Support for templates and user-defined fragment libraries.
• Plugin System: Extensible architecture for custom exporters and importers.

Recent Modernization & Stability Fixes

This version of BKChem includes significant updates to ensure compatibility with modern environments:

• Python 3 Port: Fully refactored from Python 2 to Python 3.10+, resolving all legacy syntax and library incompatibilities.
• Graphics Export Fixes:
  • Resolved critical TypeError: a bytes-like object is required crashes in Cairo-based exporters (PDF, SVG, PNG, PS).
  • Modernized the internal Piddle graphics library to correctly handle binary file I/O in Python 3.
• Text Rendering Stability: Fixed a persistent crash (NoneType object is not iterable) in the ftext engine when handling charges or single-character labels.
• Modern I/O: Shifted to standard binary file handling for all PDF and PostScript generation.

Requirements

To run BKChem, you need Python 3.10 or higher and the following libraries:

• Tkinter: (usually comes with Python)
• Pmw (Python MegaWidgets): pip install Pmw
• Pillow (PIL Fork): pip install Pillow
• PyCairo (Optional, for Cairo-based exports): pip install pycairo

Quick Start

1. Clone the repository:

   git clone https://github.com/vijaymasand/BKChem_python_3
   cd BKChem_python_3

2. Install dependencies:

   pip install Pmw Pillow pycairo

3. Launch BKChem:

   python start_bkchem.py

Support & Contribution

If you find this modernized version of BKChem helpful, please consider:

• 🌟 Giving it a Star on GitHub to help others find it.
• ☕ Buying me a coffee to support further development:

Documentation

Detailed documentation (though some of it legacy) can be found in the doc/ directory, including guides on batch mode, custom plugins, and templates.

License

BKChem is released under the GNU General Public License (GPL). See the bkchem/import_checker.py or the original project documentation for more licensing details.

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Modernization and maintenance by Dr. Vijay Masand (Amravati, India), Gaurav Masand (Amravati, India), and Krish Masand (Amravati, India)