Problem description:

When using a custom font, saving the figure as pdf format, and then opening the pdf with adobe reader (or many other pdf readers except SumatraPDF), some characters don't display correctly.

I use windows 10 operating system. The font is for the Chinese language, and already install into C:\windows\fonts

Check the font

from matplotlib.font_manager import fontManager
for f in fontManager.ttflist:
    if 'Source Han Serif' in f.name:
        print(f.name, ' : ', f.fname)

Output:

Source Han Serif CN  :  C:\Windows\Fonts\SourceHanSerifCN-Regular.otf
Source Han Serif CN  :  C:\Windows\Fonts\SourceHanSerifCN-Bold.otf

Generate the figure

Code (a minimal and fully example)

import matplotlib.pyplot as plt
from matplotlib.font_manager import FontProperties
plt.text(0.5, 0.5, '图像', ha='center', va='center', 
         fontdict={'family': 'Source Han Serif CN', 'size': 18})
plt.savefig('figure_with_font.pdf')
plt.savefig('figure_with_font.png')

There will be a warning message:

'SourceHanSerifCN-Regular.otf' cannot be subsetted into a Type 3 font. The entire font will be embedded in the output.

And the output in the notebook and the png format both displays correctly:

But when open figure_with_font.pdf with "adobe reader", it displays like:

When I check the document properties, it seems like the font is already embedded in the pdf:

I've tried some other readers, only Sumatra PDF works.

**I'm using: **

1. Windows 10
2. matplotlib: 3.0.0

And The output pdf file:

figure_with_font.pdf

Question:

• Can matplotlib save a figure to pdf without embedding the font? Sometimes when saving thousands of figures, it will help to reduce the file size.
• What's wrong with the pdf not displaying correctly?