将字体从 URL 加载到 Pillow

Question

有没有办法直接从 url 加载带有 Pillow 库的字体，最好是加载到 Google Colab 中？我尝试了类似的东西

from PIL import Image, ImageDraw, ImageFontImageFont.truetype("https://github.com/googlefonts/roboto/blob/master/src/hinted/Roboto-Regular.ttf?raw=true", 15)

但我收到 OSError: cannot open resource 的错误。我也尝试过使用谷歌字体，但无济于事。

Answer 1

你可以
(1) 通过 HTTP GET 请求获取字体，使用urllib.request.urlopen()
(2) 使用@functools.lrucache 或@memoization.cache 记住结果，这样每次运行函数时都不会获取字体，
(3) 将内容作为类文件对象传递给io.BytesIO

from PIL import ImageFont
import urllib.request
import functools
import io


@functools.lru_cache
def get_font_from_url(font_url):
    return urllib.request.urlopen(font_url).read()


def webfont(font_url):
    return io.BytesIO(get_font_from_url(font_url))


if __name__ == "__main__":
    font_url = "https://github.com/googlefonts/roboto/blob/master/src/hinted/Roboto-Regular.ttf?raw=true"
    with webfont(font_url) as f:
        imgfnt = ImageFont.truetype(f, 15)

还有python-memoization (pip install memoization) 用于替代记忆方式。用法将是

from memoization import cache 

@cache
def get_font_from_url(font_url):
    return urllib.request.urlopen(font_url).read()

记忆速度

没有记忆：

In [1]: timeit get_font_from_url(font_url)
The slowest run took 4.95 times longer than the fastest. This could mean that an intermediate result is being cached.
1.32 s ± 1.11 s per loop (mean ± std. dev. of 7 runs, 1 loop each)

有记忆：

In [1]: timeit get_font_from_url(font_url)
The slowest run took 11.00 times longer than the fastest. This could mean that an intermediate result is being cached.
271 ns ± 341 ns per loop (mean ± std. dev. of 7 runs, 1 loop each)
```t

Answer 2

试试这样：

import requests
from io import BytesIO

req = requests.get("https://github.com/googlefonts/roboto/blob/master/src/hinted/Roboto-Regular.ttf?raw=true")

font = ImageFont.truetype(BytesIO(req.content), 72)