开发平台是Mac，需要用到Python的图像处理库PIL，下面记录了安装过程以及出现的问题。
基本安装过程是这样的，使用命令pip进行安装
$ pip install PIL
Downloading/unpacking PIL
Could not find any downloads that satisfy the requirement PIL
Some externally hosted files were ignored (use --allow-external PIL to allow).
Cleaning up...
No distributions at all found for PIL
Storing debug log for failure in /Users/mylxsw/.pip/pip.log提示需要添加--allow-external参数
$ pip2.7 install PIL --allow-external PIL
Downloading/unpacking PIL
Could not find any downloads that satisfy the requirement PIL
Some insecure and unverifiable files were ignored (use --allow-unverified PIL to allow).
Cleaning up...
No distributions at all found for PIL
Storing debug log for failure in /Users/mylxsw/.pip/pip.log又报错了，提示需要添加--allow-unverified参数
$ pip2.7 install PIL --allow-external PIL --allow-unverified PIL
...
_imagingft.c:73:10: fatal error: 'freetype/fterrors.h' file not found
#include <freetype/fterrors.h>
^
1 error generated.
...提示缺少freetype/fterrors.h头文件，可是系统已经安装了，于是从stackoverflow上找到方案：
$ ln -s /usr/local/include/freetype2 /usr/local/include/freetype再次安装
代码语言：javascript复制$ pip2.7 install PIL --allow-external PIL --allow-unverified PIL
Downloading/unpacking PIL
...
Successfully installed PIL
Cleaning up...OK!
