Support partial usetex in ps output

I am trying to save some figures I made as .ps or .eps but I am getting an error. I narrowed the error down to the fact that I am using Latex for some of the text in my figure but using rc.params['text.usetex'] = False. Here is some code that reproduces the bug:

import matplotlib
import matplotlib.pyplot as plt
fig = plt.figure()
plt.text(0.5, 0.5, 'Here is some text, $math mode$', ha='center', va='center', usetex=True)
fig.savefig('test.ps')

The error you get is AttributeError: 'RendererPS' object has no attribute 'textcnt'

When looking at this code in in the RendererPS class the textcnt attribute is only added when rc.params['text.usetex'] = True. However I am just using Latex for specific text objects with the option usetex=True. Is there a way to save these figures as .ps or .eps?

I am using Matplotlib 1.5.1 installed via conda on Windows with python 2.7. I also tested it with Matplotlib 2.0.0b4 which also produced the same error, however I would prefer a solution for 1.5.1 if possible.

從 lib/matplotlib/backends/backend_ps.py 和 RendererPS 對 textcnt 的處理開始，然後執行 issue 中將圖形儲存為 test.ps 的最小 Python 範例。確認在全域設定為 false 時使用 usetex=True 的文字物件行為；當 PS 和 EPS 輸出能夠在不出現所回報的 AttributeError 的情況下儲存時，即表示完成。