import matplotlib.pyplot 给出 ImportError: dlopen(...) Library not loaded libpng15.15.dylib答案

【问题标题】：import matplotlib.pyplot gives ImportError: dlopen(...) Library not loaded libpng15.15.dylibimport matplotlib.pyplot 给出 ImportError: dlopen(...) Library not loaded libpng15.15.dylib
【发布时间】：2015-02-01 14:51:57
【问题描述】：

导入pyplot报错：

In [1]: import matplotlib
In [2]: import matplotlib.pyplot as plt
ImportError                               Traceback (most recent call last)
<ipython-input-2-eff513f636fd> in <module>()
----> 1 import matplotlib.pyplot as plt
/Users/r8t/anaconda/lib/python2.7/site-packages/matplotlib/pyplot.py in <module>()
     25
     26 import matplotlib
---> 27 import matplotlib.colorbar
     28 from matplotlib import style
     29 from matplotlib import _pylab_helpers, interactive

/Users/r8t/anaconda/lib/python2.7/site-packages/matplotlib/colorbar.py in <module>()
     32 import matplotlib.artist as martist
     33 import matplotlib.cbook as cbook
---> 34 import matplotlib.collections as collections
     35 import matplotlib.colors as colors
     36 import matplotlib.contour as contour
/Users/r8t/anaconda/lib/python2.7/site-packages/matplotlib/collections.py in <module>()
     25 import matplotlib.artist as artist
     26 from matplotlib.artist import allow_rasterization
---> 27 import matplotlib.backend_bases as backend_bases
     28 import matplotlib.path as mpath
     29 from matplotlib import _path
/Users/r8t/anaconda/lib/python2.7/site-packages/matplotlib/backend_bases.py in <module>()
     54
     55 import matplotlib.tight_bbox as tight_bbox
---> 56 import matplotlib.textpath as textpath
     57 from matplotlib.path import Path
     58 from matplotlib.cbook import mplDeprecation
/Users/r8t/anaconda/lib/python2.7/site-packages/matplotlib/textpath.py in <module>()
     20 from matplotlib.ft2font import FT2Font, KERNING_DEFAULT, LOAD_NO_HINTING
     21 from matplotlib.ft2font import LOAD_TARGET_LIGHT
 ---> 22 from matplotlib.mathtext import MathTextParser
     23 import matplotlib.dviread as dviread
     24 from matplotlib.font_manager import FontProperties

/Users/r8t/anaconda/lib/python2.7/site-packages/matplotlib/mathtext.py in <module>()
     61
     62 import matplotlib.colors as mcolors
---> 63 import matplotlib._png as _png
     64 ####################
     65
 ImportError: dlopen(/Users/r8t/anaconda/lib/python2.7/site-packages/matplotlib/_png.so, 2): Library   not loaded: libpng15.15.dylib
  Referenced from: /Users/r8t/anaconda/lib/python2.7/site-packages/matplotlib/_png.so
  Reason: image not found

我看过Error importing matplotlib.pyplot 这建议删除 matplotlib 文件夹。我试过了，但没有用。这也没有解决方案，但我认为是相关的：Python: py2app "ImportError: dlopen(): Library not loaded"

我还确定我已经安装了 libpng（通过 brew）。谢谢，

【问题讨论】：

我也尝试通过 pip 卸载 matplot lib，然后 brew 重新安装 libpng 和 freetype，然后 pip 安装 matplotlib，我得到同样的错误......呃。

标签： macos matplotlib libpng

【解决方案1】：

（对不起，我还不能评论..所以这是一个新帖子）

我在安装另一个库（spynner）时遇到了同样的问题：dlopen(…) Library not loaded libpng15.15.dylib

我尝试了与@travelingbones 的答案类似的方法，只是想为未来的读者添加一些注释：

DYLD_LIBRARY_PATH 应该包含目录，而不是文件。例如，

export DYLD_LIBRARY_PATH=/Users/xxx/anaconda/lib:$DYLD_LIBRARY_PATH

而不是

export DYLD_LIBRARY_PATH=/Users/xxx/anaconda/lib/libpng15.15.dylib:$DYLD_LIBRARY_PATH

错误/usr/X11/lib/libpng15.15.dylib/libpng15.15.dylib: stat() failed with errno=20是由错误的DYLD_LIBRARY_PATH引起的，因为文件路径/usr/X11/lib/libpng15.15.dylib/libpng15.15.dylib不存在（注意文件路径中的双libpng15.15.dylib）。

设置新的 DYLD_LIBRARY_PATH 后，我发现我的 matplotlib 搞砸了，出现以下错误：

ImportError: dlopen(/Users/shenggao/anaconda/lib/python2.7/site-packages/matplotlib/backends/_macosx.so, 2): Symbol not found: __cg_jpeg_resync_to_restart
Referenced from: /System/Library/Frameworks/ImageIO.framework/Versions/A/ImageIO
Expected in: /Users/shenggao/anaconda/lib/libjpeg.8.dylib in /System/Library/Frameworks/ImageIO.framework/Versions/A/ImageIO

为了解决这个问题，我将 DYLD_LIBRARY_PATH 改回旧值（即 empty），并将 libpng 路径添加到 DYLD_FALLBACK_LIBRARY_PATH 像这样：

export DYLD_FALLBACK_LIBRARY_PATH=/Users/shenggao/anaconda/lib:$DYLD_FALLBACK_LIBRARY_PATH

终于 matplotlib 和我的新库像魅力一样工作了！

【讨论】：

酷！感谢分享。从那以后，我重新映像了我的 mac，并使用 brew 和 pip 重新安装了所有 python。从那以后一切都运行良好。如果您愿意擦除您的机器并从新的操作系统开始，我认为这是另一种解决方案。

【解决方案2】：

我关注了these directions，得到了一个可以修复的不同错误：首先，我检查了该路径中的内容：

macair93278:~ r8t$ echo $DYLD_LIBRARY_PATH

(empty)

接下来找到我需要的文件（libpng15.15.dylib）：

macair93278:~ r8t$ locate libpng15.15.dylib
/Applications/KeePassX.app/Contents/MacOS/libpng15.15.dylib
/Users/r8t/anaconda/lib/libpng15.15.dylib
/Users/r8t/anaconda/pkgs/libpng-1.5.13-1/lib/libpng15.15.dylib
/usr/X11/lib/libpng15.15.dylib

现在我将底部三个附加到路径并检查路径：

macair93278:~ r8t$ echo $DYLD_LIBRARY_PATH  
/usr/X11/lib/libpng15.15.dylib:/Users/r8t/anaconda/pkgs/libpng-1.5.13-1/lib/libpng15.15.dylib:/Users/r8t/anaconda/lib/libpng15.15.dylib

好的，现在开始测试，

macair93278:~ r8t$ ipython

In [1]: import matplotlib

In [2]: from matplotlib import pyplot
…(bunch of output)
ImportError: dlopen(/Users/r8t/anaconda/lib/python2.7/site-packages/matplotlib/_png.so, 2): Library not loaded: libpng15.15.dylib
Referenced from: /Users/r8t/anaconda/lib/python2.7/site-packages/matplotlib/_png.so
Reason: no suitable image found. Did find:
/usr/X11/lib/libpng15.15.dylib/libpng15.15.dylib: stat() failed with errno=20
/Users/r8t/anaconda/pkgs/libpng-1.5.13-1/lib/libpng15.15.dylib/libpng15.15.dylib: stat() failed with errno=20
/Users/r8t/anaconda/lib/libpng15.15.dylib/libpng15.15.dylib: stat() failed with errno=20

另一个错误！进步！现在在this page 之后，我运行了 brew 链接，然后取消链接它并没有修复它，但它指出了 pyplot 正在 usr/local/lib 中寻找 libpng15.15.dylib 但它们不存在的事实：

macair93278:~ r8t$ cd ../usr/local/lib
macair93278:lib r8t$ ls *png*
libpng.a libpng16.16.dylib libpng16.dylib
libpng.dylib libpng16.a

所以把它们复制到那里：

macair93278:~ r8t$ cp ../anaconda/lib/*png* /usr/local/lib
macair93278:~ r8t$ cd /usr/local/lib

测试：

In [1]: import matplotlib 

In [2]: from matplotlib import pyplot
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/r8t/anaconda/lib/python2.7/site-packages/matplotlib/pyplot.py", line 109, in <module>
_backend_mod, new_figure_manager, draw_if_interactive, _show = pylab_setup()
  File "/Users/r8t/anaconda/lib/python2.7/site-packages/matplotlib/backends/__init__.py", line 32, in pylab_setup
    globals(),locals(),[backend_name],0)
  File "/Users/r8t/anaconda/lib/python2.7/site-packages/matplotlib/backends/backend_macosx.py", line 24, in <module>
    from matplotlib.backends import _macosx
RuntimeError: Python is not installed as a framework. The Mac OS X backend will not be able to function correctly if Python is not installed as a framework. See the Python documentation for more information on installing Python as a framework on Mac OS X. Please either reinstall Python as a framework, or try one of the other backends.

我们已将问题简化为这个（已解决的）问题：problem w/ mac os backend

【讨论】：