Python script to convert TTF and/or OTF font files to WOFF fonts

python_font_converter.py

"""
Font Converter Script

This script converts TrueType Font (TTF) and OpenType Font (OTF) files to Web Open Font Format (WOFF).

Usage:
1. Set the paths to your TTF font folder and WOFF output folder in the variables `font_folder` and `woff_folder`, respectively.
2. Run the script.

Dependencies:
- This script requires the `pyftsubset` tool from the `fontTools` Python library.
- Install fontTools via pip: `pip install fonttools`.

Author: Theo van der Sluijs
Email: info@itheo.tech
Date: 12 May 2024
License: MIT License
Project URL: https://tvdsluijs.github.io/python-font-converter
Author URL: https://itheo.tech
"""

import os
import subprocess
import sys

def ttf_to_woff(ttf_path, woff_path):
    """
    Convert a TrueType Font (TTF) file to Web Open Font Format (WOFF) using pyftsubset.

    Args:
        ttf_path (str): Path to the input TTF file.
        woff_path (str): Path to save the output WOFF file.

    Returns:
        bool: True if conversion is successful, False otherwise.
    """
    try:
        # Use pyftsubset to convert TTF to WOFF
        subprocess.run(['pyftsubset', ttf_path, '--flavor=woff', '--output-file=' + woff_path], check=True, stderr=subprocess.PIPE)
        return True
    except subprocess.CalledProcessError as e:
        print(f"Error converting {ttf_path} to WOFF:")
        print(e.stderr.decode(sys.getfilesystemencoding()).strip())
        return False

def otf_to_woff(otf_path, woff_path):
    """
    Convert an OpenType Font (OTF) file to Web Open Font Format (WOFF) using pyftsubset.

    Args:
        otf_path (str): Path to the input OTF file.
        woff_path (str): Path to save the output WOFF file.

    Returns:
        bool: True if conversion is successful, False otherwise.
    """
    try:
        # Use pyftsubset to convert OTF to WOFF
        subprocess.run(['pyftsubset', otf_path, '--flavor=woff', '--output-file=' + woff_path], check=True, stderr=subprocess.PIPE)
        return True
    except subprocess.CalledProcessError as e:
        print(f"Error converting {otf_path} to WOFF:")
        print(e.stderr.decode(sys.getfilesystemencoding()).strip())
        return False

def convert_folder_fonts_to_woff(font_folder, woff_folder):
    """
    Convert all TrueType Font (TTF) and OpenType Font (OTF) files in a folder to Web Open Font Format (WOFF).

    Args:
        font_folder (str): Path to the folder containing TTF and/or OTF files.
        woff_folder (str): Path to save the converted WOFF files.
    """
    ttf_count = 0  # Counter for processed TTF files
    woff_count = 0  # Counter for created WOFF files

    # Create the WOFF folder if it doesn't exist
    if not os.path.exists(woff_folder):
        os.makedirs(woff_folder)

    # Loop through all font files in the folder
    for filename in os.listdir(font_folder):
        if filename.endswith('.ttf'):
            ttf_count += 1
            font_path = os.path.join(font_folder, filename)
            woff_filename = os.path.splitext(filename)[0] + '.woff'
            woff_path = os.path.join(woff_folder, woff_filename)
            try:
                if ttf_to_woff(font_path, woff_path):
                    woff_count += 1
            except subprocess.CalledProcessError:
                otf_path = os.path.join(font_folder, os.path.splitext(filename)[0] + '.otf')
                if os.path.exists(otf_path):
                    ttf_count -= 1
                    try:
                        if otf_to_woff(otf_path, woff_path):
                            woff_count += 1
                    except subprocess.CalledProcessError as e:
                        print(f"Error converting both {filename} (TTF) and {os.path.splitext(filename)[0]}.otf to WOFF:")
                        print(e.stderr.decode(sys.getfilesystemencoding()).strip())
                else:
                    print(f"Error converting {filename} (TTF) to WOFF:")
        # ONLY uncomment this code when you also want to process all remaining OTF files
        # elif filename.endswith('.otf'):
        #     font_path = os.path.join(font_folder, filename)
        #     woff_filename = os.path.splitext(filename)[0] + '.woff'
        #     woff_path = os.path.join(woff_folder, woff_filename)
        #     try:
        #         if otf_to_woff(font_path, woff_path):
        #             woff_count += 1
        #     except subprocess.CalledProcessError as e:
        #         print(f"Error converting {filename} (OTF) to WOFF:")
        #         print(e.stderr.decode(sys.getfilesystemencoding()).strip())

    print(f"Processed {ttf_count} TTF files")
    print(f"Created {woff_count} WOFF files")

font_folder = "[path to your font ttf folder]"
woff_folder = "[path to your output woff folder]"
convert_folder_fonts_to_woff(font_folder, woff_folder)