fpdf解决中文报错的方法

将字体从C:\Windows\Fonts目录下拷贝到了fpdf文件夹。如果打印的字是'你好世界'时不会报错。但是换为其他字时就报cmap value too big/small
import fpdf
pdf =fpdf.FPDF()
pdf.add_font('STSONG','',r'D:\test\venv\Lib\site-packages\fpdf\STSONG.TTF',True)
#此句话添加字体标准宋体
pdf.add_page()
pdf.set_font('STSONG', '', 35)#设置字体为标准宋体，size为35
pdf.cell(100, 100,'跟我说谢谢你')
pdf.output('helloword_01.pdf')

报错：

D:\test\venv\Scripts\python.exe D:/test/pdf操作/fpdftest.py 
D:\test\venv\lib\site-packages\fpdf\ttfonts.py:670: UserWarning: cmap value too big/small: -35825
  warnings.warn("cmap value too big/small: %s" % cm)
D:\test\venv\lib\site-packages\fpdf\ttfonts.py:670: UserWarning: cmap value too big/small: -35869
  warnings.warn("cmap value too big/small: %s" % cm)
D:\test\venv\lib\site-packages\fpdf\ttfonts.py:670: UserWarning: cmap value too big/small: -36318
  warnings.warn("cmap value too big/small: %s" % cm)
Traceback (most recent call last):
  File "D:\test\pdf操作\fpdftest.py", line 12, in <module>
    pdf.output('helloword_01.pdf')
  File "D:\test\venv\lib\site-packages\fpdf\fpdf.py", line 1079, in output
    f=open(name,'wb')
PermissionError: [Errno 13] Permission denied: 'helloword_01.pdf'

Process finished with exit code 1

点击报错中的ttfonts.py，将else及其后边几句注释掉后，竟然不报错了，并且能正常生成中文。

cmap.append(0)    # Mapping for last character
cmapstr = b('')
for cm in cmap:
    if cm >= 0:
        cmapstr += pack(">H", cm) 
    # else:
    #     try:
    #         cmapstr += pack(">h", cm)
    #     except:
    #         warnings.warn("cmap value too big/small: %s" % cm)
    #         cmapstr += pack(">H", -cm)