Python: matplotlib のインポートエラー

Python

久々に Python でグラフを書こうとして

import pylab

としたときにエラー。

Traceback (most recent call last):
File "", line 1, in
File "/usr/local/lib/python2.7/site-packages/pylab.py", line 1, in
from matplotlib.pylab import *
File "/usr/local/lib/python2.7/site-packages/matplotlib/pylab.py", line 226, in
import matplotlib.finance
File "/usr/local/lib/python2.7/site-packages/matplotlib/finance.py", line 23, in
from matplotlib.collections import LineCollection, PolyCollection
File "/usr/local/lib/python2.7/site-packages/matplotlib/collections.py", line 23, in
import matplotlib.backend_bases as backend_bases
File "/usr/local/lib/python2.7/site-packages/matplotlib/backend_bases.py", line 50, in
import matplotlib.textpath as textpath
File "/usr/local/lib/python2.7/site-packages/matplotlib/textpath.py", line 14, in
from matplotlib.mathtext import MathTextParser
File "/usr/local/lib/python2.7/site-packages/matplotlib/mathtext.py", line 62, in
import matplotlib._png as _png
ImportError: dlopen(/usr/local/lib/python2.7/site-packages/matplotlib/_png.so, 2): Library not loaded: /usr/local/lib/libpng15.15.dylib
Referenced from: /usr/local/lib/python2.7/site-packages/matplotlib/_png.so
Reason: image not found

で、解決方法。
ダイナミックライブラリが死んでたっぽいので再インストールする。
(libpng, freetype の --universal フラグは必要)

sudo pip uninstall matplotlib
sudo rm -rf /tmp/pip-build-root/
brew reinstall libpng --universal
brew reinstall freetype --universal
sudo pip install matplotlib

References