FontsToCss: Convert a font or zip of fonts to a .css with embedded @font-face base64 data

fonts_to_css.py

# FONTS TO CSS
#
# Convert a font or zip of fonts to a .css with embedded @font-face base64 data.
#
# Install Python: https://www.python.org/downloads/
#   NOTE: Check "Add Python to environment variables" during Windows install
# Using Command Line:
#   pip install fonttools
#   python convert.py <path_to_font_or_zip_of_fonts>
import base64
import os
import zipfile
import sys
from fontTools.ttLib import TTFont, woff2

def font_to_base64(font_path):
    with open(font_path, "rb") as font_file:
        encoded_string = base64.b64encode(font_file.read()).decode('utf-8')
    return encoded_string

def get_font_properties(font_path):
    font = TTFont(font_path)
    name = font['name']
    family_name = name.getName(1, 3, 1, 1033).toStr()
    subfamily_name = name.getName(2, 3, 1, 1033).toStr()

    font_weight = "normal"
    font_style = "normal"

    # Extract font weight
    os2 = font['OS/2']
    if os2.usWeightClass:
        font_weight = os2.usWeightClass

    # Extract font style
    if "Italic" in subfamily_name or "Oblique" in subfamily_name:
        font_style = "italic"

    return family_name, font_weight, font_style

def convert_woff_to_ttf(font_path):
    ttf_path = font_path.replace('.woff', '.ttf').replace('.woff2', '.ttf')
    woff2.decompress(font_path, ttf_path)
    return ttf_path

def create_css(font_files, output_css):
    with open(output_css, "w") as css_file:
        for font_path in font_files:
            print(f"Adding @font-face for '{os.path.basename(font_path)}'")

            # Convert all fonts to TTF to get consistent properties for family name, style and weight
            if font_path.endswith(('.woff', '.woff2')):
                font_path = convert_woff_to_ttf(font_path)
            family_name, font_weight, font_style = get_font_properties(font_path)
            base64_string = font_to_base64(font_path)
            css_file.write(f"@font-face {{\n")
            css_file.write(f"    font-family: '{family_name}';\n")
            css_file.write(f"    src: url('data:font/ttf;charset=utf-8;base64,{base64_string}') format('truetype');\n")
            css_file.write(f"    font-weight: {font_weight};\n")
            css_file.write(f"    font-style: {font_style};\n")
            css_file.write(f"    font-display: swap;\n")
            css_file.write(f"}}\n\n")

def is_font_file(filename):
    return filename.lower().endswith(('.ttf', '.otf', '.woff', '.woff2'))
 
def is_zip_file(filename):
    return filename.lower().endswith('.zip')

def process_zip(zip_path, output_css):
    with zipfile.ZipFile(zip_path, 'r') as zip_ref:
        zip_ref.extractall("temp_fonts")
        font_files = []
        for root, _, files in os.walk("temp_fonts"):
            for filename in files:
                if is_font_file(filename):
                    font_files.append(os.path.join(root, filename))
        create_css(font_files, output_css)

def process_font(filename, output_css):
    if is_font_file(filename):
        create_css([filename], output_css)

if __name__ == "__main__":
    if len(sys.argv) == 2:
        filename = sys.argv[1]
        output_css = "output.css"

        if (is_zip_file(filename)):
            process_zip(filename, output_css)
        elif (is_font_file(filename)):
            process_font(filename, output_css)
        else:
            print(f"'{filename}' is not a .zip file or a font file")
            sys.exit(1)
    else:
        print("Usage: python fonts_to_css.py <path_to_zip_file>")
        sys.exit(1)