py之ttf字库解析并渲染

import freetype
from PIL import Image, ImageDraw


def _convert_bitmap_to_bytes(bitmap) -> bytes:
    """将FreeType位图转换为字节数据（1bpp格式）"""
    if bitmap.width == 0 or bitmap.rows == 0:
        return b''

    bytes_per_line = (bitmap.width + 7) // 8
    result = bytearray()

    for y in range(bitmap.rows):
        for x in range(0, bitmap.width, 8):
            byte_val = 0
            for bit in range(8):
                if x + bit < bitmap.width:
                    pixel_x = x + bit
                    byte_index = y * bitmap.pitch + pixel_x // 8
                    bit_mask = 0x80 >> (pixel_x % 8)
                    if byte_index < len(bitmap.buffer):
                        if bitmap.buffer[byte_index] & bit_mask:
                            byte_val |= (1 << (7 - bit))
            result.append(byte_val)
    return bytes(result)


def draw_bitmap_to_canvas(bitmap_data, width, height, left, top, output_path="char.png"):
    """将位图数据绘制到画布上"""
    # 创建白色背景画布（RGB模式）
    canvas_width = width + 20
    canvas_height = height + 20
    img = Image.new("RGB", (canvas_width, canvas_height), "white")
    draw = ImageDraw.Draw(img)


    baseline_y=(canvas_height)//2
    baseline_x=(canvas_width-width)//2

    # 绘制黑色像素点（1bpp数据）
    for y in range(height):
        for x in range(width):
            byte_pos = y * ((width + 7) // 8) + x // 8
            bit_pos = 7 - (x % 8)
            if byte_pos < len(bitmap_data):
                if (bitmap_data[byte_pos] >> bit_pos) & 0x01:
                    # 正确的坐标计算：
                    # x坐标：原点 + 水平偏移 + 当前x
                    # y坐标：基线 - 垂直偏移 + 当前y（FreeType坐标系转PIL坐标系）
                    pixel_x =baseline_x+  left + x
                    pixel_y = baseline_y - top + y  # 这是关键修正！
                    if 0 <= pixel_x < canvas_width and 0 <= pixel_y < canvas_height:
                        draw.point((pixel_x, pixel_y), fill="black")

                    # 考虑位图偏移 (left, top)
                    # draw.point((left + x + 10, 10 + top - y), fill="black")  # 调整基线

    # 标记参考线（基线）
    draw.line([(0, 10 + top), (width + 20, 10 + top)], fill="red", width=1)

    img.save(output_path)
    print(f"字符已保存到 {output_path}")
    img.show()


# 初始化FreeType
face = freetype.Face('Roboto-Regular.ttf')  # 替换为你的字体文件路径
face.set_char_size(16 * 64)  # 16像素高度（26.6格式）

# 加载并渲染字符'0'（Unicode 0x30）
char_code = 'Z'
face.load_char(char_code, freetype.FT_LOAD_RENDER | freetype.FT_LOAD_TARGET_MONO)

bitmap = face.glyph.bitmap
glyph = face.glyph

# 生成点阵数据
char_bitmap = _convert_bitmap_to_bytes(bitmap)

# 打印信息
print("位图大小:", len(char_bitmap))
print("位图宽度:", bitmap.width)
print("位图高度:", bitmap.rows)
print("位图偏移X:", glyph.bitmap_left)  # 水平偏移（从原点向右）
print("位图偏移Y:", glyph.bitmap_top)  # 垂直偏移（从基线向上）
print("Advance:", glyph.advance.x >> 6, "像素")  # 下一个字符的起始位置

# 绘制到画布
draw_bitmap_to_canvas(
    char_bitmap,
    width=bitmap.width,
    height=bitmap.rows,
    left=glyph.bitmap_left,
    top=glyph.bitmap_top,
    output_path="char_render.png"
)