matplotlib 不检测字体

Question

当我将fontname= 与Humor Sans 字体一起使用时，我收到此错误：

/usr/lib/python3.5/site-packages/matplotlib/font_manager.py:1288: UserWarning: findfont: Font family ['Humor Sans', 'Comic Sans MS'] not found. Falling back to Bitstream Vera Sans
  (prop.get_family(), self.defaultFamily[fontext]))

我安装了Humor Sans。我用的是archlinux，我安装了ttf-humor-sans包。

我已确保字体配置缓存 fc-list 找到 Humor Sans 字体：

$ fc-list | grep -i Humor
/usr/share/fonts/TTF/Humor-Sans-1.0.ttf: Humor Sans:style=Regular

Answer 1

好吧，仔细看后，它是一种错误。使用以下测试：

import matplotlib.font_manager as fm
import matplotlib.pyplot as plt

font_cache = [i for i in
    fm.findSystemFonts(fontpaths=None, fontext='ttf')
    if 'umor' in i]
for i in font_cache:
    print(i)
fig = plt.figure()
ax = fig.add_subplot(111)
ax.plot([1],[1],'o')
ax.set_title('My Title', fontname='Humor Sans')
#ax.set_title('My Title', fontname='Homemade Apple')
fig.savefig('tmp.png')

我已经比较了 Humor Sans 和 Homemade Apple（我打包到 AUR 包中的免费 google 字体）的行为。问题是matplotlib 对fontname= 中指定的字体名称进行匹配，匹配不仅使用名称，还使用字体的几个属性。在/home/grochmal/mat3/lib/python3.5/site-packages/matplotlib/font_manager.py 你看到匹配：

for font in fontlist:
    if (directory is not None and
        os.path.commonprefix([font.fname, directory]) != directory):
        continue
    # Matching family should have highest priority, so it is multiplied
    # by 10.0
    score = \
        self.score_family(prop.get_family(), font.name) * 10.0 + \
        self.score_style(prop.get_style(), font.style) + \
        self.score_variant(prop.get_variant(), font.variant) + \
        self.score_weight(prop.get_weight(), font.weight) + \
        self.score_stretch(prop.get_stretch(), font.stretch) + \
        self.score_size(prop.get_size(), font.size)
    if score < best_score:
         best_score = score
         best_font = font
    if score == 0:
         break

不幸的是，Humor Sans 从未达到匹配阶段，因为并非所有prop.get_... 都可以填写。本质上，它永远不会包含在fontlist 中。包含Homemade Apple，因为它可以填充所有属性。

字体属性的区别可以看如下：

[me@haps aur]# otfinfo --info /usr/share/fonts/TTF/HomemadeApple.ttf
Family:              Homemade Apple
Subfamily:           Regular
Full name:           Homemade Apple
PostScript name:     HomemadeApple
Preferred family:    Homemade Apple
Preferred subfamily: Regular
Mac font menu name:  Homemade Apple
Version:             Version 1.000
Unique ID:           FontDiner,Inc: Homemade Apple: 2010
Description:         Copyright (c) 2010 by Font Diner, Inc. All rights reserved.
Designer:            Font Diner, Inc
Designer URL:        http://www.fontdiner.com
Manufacturer:        Font Diner, Inc
Vendor URL:          http://www.fontdiner.com
Trademark:           Homemade Apple is a trademark of Font Diner, Inc.
Copyright:           Copyright (c) 2010 by Font Diner, Inc. All rights reserved.
License URL:         http://www.apache.org/licenses/LICENSE-2.0
License Description: Licensed under the Apache License, Version 2.0
Vendor ID:           DINR

[me@haps aur]# otfinfo --info /usr/share/fonts/TTF/Humor-Sans-1.0.ttf
Family:              Humor Sans
Subfamily:           Regular
Full name:           Humor Sans
PostScript name:     HumorSans
Version:             Version 2.9 28/3/09
Unique ID:           Fontifier 2.9 (172) www.fontifier.com Humor Sans
Copyright:           Copyright (c) Randall Munroe's biggest fan 2009. Created by www.fontifier.com. usa-1lip-4fvu15
Vendor ID:           Alts

Humor Sans 中缺少的字段不是必需的，公平地说，TTF 中字体的描述方式存在一些不一致（google italic vs. oblique示例）因此也不是Humor Sans 错误。您的问题是文件格式不一致以及缺乏处理它们的标准化代码的组合。

我建议找一种看起来足够相似的不同字体。编辑 TTF 或 matplotlib 代码都非常棘手，可能会导致其他问题。

Answer 2

来自 AUR 的 Humor Sans 适合我。但是，我必须先删除字体缓存：
rm ~/.cache/matplotlib/fontlist-v330.json.

见https://stackoverflow.com/a/22812176