Python 3.3 + Matplotlib 1.2.0: pdf导出生成"'str‘不支持缓冲区接口“错误

Question

我刚开始从matlab/mathematica迁移到python进行技术计算。我一直在学习如何使用matplotlib.pyplot包，希望有人能帮助我处理字体。我最终需要将图形输出保存为pdf或eps文件，以便在Adobe Illustrator中打开。最初，我的pdf和eps输出包含轮廓字体(而不是保留文本信息的嵌入式字体)。在this helpful advice之后，我得到了以下代码：

import matplotlib as mpl
import matplotlib.pyplot as plt
# if I omit the next line, the plot saves without error, but with outlined fonts
mpl.rcParams['pdf.fonttype'] = 42        #set Truetype fonts for Adobe
plt.plot(range(5),range(5),'r-')
plt.ylabel('y')
plt.xlabel('x')
plt.title('title')
plt.show()
plt.savefig("myfig.pdf")

但是，当我设置rcParams‘pdf.fonttype’=42时，最后一行生成下面复制的错误。有谁能给我指个方向吗？我运行的是Python3.3和matplotlib 1.2.0，使用的是MacOS10.6上的Pyzo发行版。

Traceback (most recent call last):
  File "<tmp 1>", line 11, in <module> plt.savefig("myfig.pdf")
  File "/Applications/pyzo2013b/lib/python3.3/pyzo-packages/matplotlib/pyplot.py", line 472, in savefig
    return fig.savefig(*args, **kwargs)
   File "/Applications/pyzo2013b/lib/python3.3/pyzo-packages/matplotlib/figure.py", line 1364, in savefig
     self.canvas.print_figure(*args, **kwargs)
  File "/Applications/pyzo2013b/lib/python3.3/pyzo-packages/matplotlib/backends/backend_qt4agg.py", line 161, in print_figure
    FigureCanvasAgg.print_figure(self, *args, **kwargs)
  File "/Applications/pyzo2013b/lib/python3.3/pyzo-packages/matplotlib/backend_bases.py", line 2093, in print_figure
    **kwargs)
  File "/Applications/pyzo2013b/lib/python3.3/pyzo-packages/matplotlib/backend_bases.py", line 1845, in print_pdf
    return pdf.print_pdf(*args, **kwargs)
  File "/Applications/pyzo2013b/lib/python3.3/pyzo-packages/matplotlib/backends/backend_pdf.py", line 2307, in print_pdf
    file.close()
  File "/Applications/pyzo2013b/lib/python3.3/pyzo-packages/matplotlib/backends/backend_pdf.py", line 507, in close
    self.writeFonts()
  File "/Applications/pyzo2013b/lib/python3.3/pyzo-packages/matplotlib/backends/backend_pdf.py", line 607, in writeFonts
    fonts[Fx] = self.embedTTF(realpath, chars[1])
  File "/Applications/pyzo2013b/lib/python3.3/pyzo-packages/matplotlib/backends/backend_pdf.py", line 1054, in embedTTF
    return embedTTFType42(font, characters, descriptor)
  File "/Applications/pyzo2013b/lib/python3.3/pyzo-packages/matplotlib/backends/backend_pdf.py", line 987, in embedTTFType42
    self.currentstream.write(unicode_cmap)
  File "/Applications/pyzo2013b/lib/python3.3/pyzo-packages/matplotlib/backends/backend_pdf.py", line 379, in write
    compressed = self.compressobj.compress(data)
TypeError: 'str' does not support the buffer interface

Answer 1

这是matplotlib中的一个错误，已在此处修复：https://github.com/matplotlib/matplotlib/pull/1978#issuecomment-17493157