bitmap_fonts.py

from PIL import Image
import struct
import os
import re

def gb2312_offset(char, size):
    gb = char.encode('gb2312')
    area = gb[0] - 0xA1
    index = gb[1] - 0xA1
    bytes_per_char = size * size // 8
    return (94 * area + index) * bytes_per_char

def read_bitmap(char, font_path, size):
    bytes_per_char = size * size // 8
    offset = gb2312_offset(char, size)
    file_size = os.path.getsize(font_path)
    if offset + bytes_per_char > file_size:
        raise ValueError("Offset out of bounds")
    with open(font_path, 'rb') as f:
        f.seek(offset)
        data = f.read(bytes_per_char)
        if not any(data):
            raise ValueError("Bitmap is all zeros")
        return data


def bitmap_to_pil(bitmap_bytes, size):
    img = Image.new('1', (size, size), 0)
    pixels = img.load()
    row_bytes = size // 8
    for y in range(size):
        for x in range(size):
            byte_index = y * row_bytes + x // 8
            if byte_index >= len(bitmap_bytes):
                continue
            byte = bitmap_bytes[byte_index]
            if byte & (1 << (7 - (x % 8))):
                pixels[x, y] = 1
    return img

def concat_pil_images_horizontally(images):
    widths, heights = zip(*(i.size for i in images))
    total_width = sum(widths)
    max_height = max(heights)
    new_image = Image.new('RGB', (total_width, max_height))
    x_offset = 0
    for img in images:
        new_image.paste(img.convert('RGB'), (x_offset, 0))
        x_offset += img.width
    return new_image

def infer_size_from_filename(name):
    m = re.search(r'(\d+)', name)
    return int(m.group(1)) if m else 16

scale = 5
font_dir = 'BitmapFont/font'
fonts = sorted(os.listdir(font_dir))

for char in '他是一个老师':
    font_samples = []
    for fontname in fonts:
        path = os.path.join(font_dir, fontname)
        try:
            size = infer_size_from_filename(fontname.upper())
            print(size)
            bitmap = read_bitmap(char, path, size)
            img = bitmap_to_pil(bitmap, size)
            img = img.resize((size*scale, size*scale), resample=Image.NEAREST)
            font_samples.append(img)
        except Exception as e:
            print(f"Skipping {fontname}: {e}")
    img_row = concat_pil_images_horizontally(font_samples)
    #display(img_row)
    img_row.save(f'output/{char}.png')