SVG是一种矢量图格式，是Scalable Vector Graphics三个单词的首字母缩写。它是基于XML（Extensible Markup Language），由World Wide Web Consortium（W3C）联盟进行开发的。严格来说应该是一种开放标准的矢量图形语言，可让你设计激动人心的、高分辨率的Web图形页面。用户可以直接用代码来描绘图像，可以用任何文字处理工具打开SVG图像，通过改变部分代码来使图像具有交互功能，并可以随时插入到HTML中通过浏览器来观看。
环境：Ubuntu 18.04 LTS
Python版本：Python 3.6.7
首先要安装 pygal：
linuxidc@linuxidc:~/linuxidc.com$ pip3 install pygal
Collecting pygal
Downloading https://files.pythonhosted.org/packages/5f/b7/201c9254ac0d2b8ffa3bb2d528d23a4130876d9ba90bc28e99633f323f17/pygal-2.4.0-py2.py3-none-any.whl (127kB)
100% |████████████████████████████████| 133kB 231kB/s
Installing collected packages: pygal
Successfully installed pygal-2.4.0
如果你要把生成格式设为除了 svg 之外的格式，比如 png，jpg 图片格式，就要安装以下这几个库了：
linuxidc@linuxidc:~/linuxidc.com$ pip3 install lxml -i https://pypi.douban.com/simple/
Collecting lxml
Downloading https://pypi.doubanio.com/packages/35/8a/5e066949f2b40caac32c7b2a77da63ad304b5fbe869036cc3fe4a198f724/lxml-4.3.3-cp36-cp36m-manylinux1_x86_64.whl (5.7MB)
100% |████████████████████████████████| 5.7MB 12.6MB/s
Installing collected packages: lxml
Successfully installed lxml-4.3.3
在 Ubuntu 中按照如下提示安装即可：
linuxidc@linuxidc:~/linuxidc.com$ sudo apt-get install libxml2-dev libxslt1-dev python-dev
linuxidc@linuxidc:~/linuxidc.com$ sudo apt-get install python-lxml
linuxidc@linuxidc:~/linuxidc.com$ pip3 install cairosvg -i https://pypi.douban.com/simple/
安装该库原理同上：
linuxidc@linuxidc:~/linuxidc.com$ sudo apt-get install python-cairosvg
如下两个库，只需正常 pip3 安装即可：
linuxidc@linuxidc:~/linuxidc.com$ pip3 install tinycss -i https://pypi.douban.com/simple/
Collecting tinycss
Downloading https://pypi.doubanio.com/packages/05/59/af583fff6236c7d2f94f8175c40ce501dcefb8d1b42e4bb7a2622dff689e/tinycss-0.4.tar.gz (87kB)
100% |████████████████████████████████| 92kB 824kB/s
Building wheels for collected packages: tinycss
Running setup.py bdist_wheel for tinycss ... done
Stored in directory: /home/linuxidc/.cache/pip/wheels/00/1e/22/af03548f887c6f9a423f72f819c46a4df9e2aabbb9480be30b
Successfully built tinycss
Installing collected packages: tinycss
Successfully installed tinycss-0.4
linuxidc@linuxidc:~/linuxidc.com$ pip3 install cssselect -i https://pypi.douban.com/simple/
Collecting cssselect
Downloading https://pypi.doubanio.com/packages/7b/44/25b7283e50585f0b4156960691d951b05d061abf4a714078393e51929b30/cssselect-1.0.3-py2.py3-none-any.whl
Installing collected packages: cssselect
Successfully installed cssselect-1.0.3
Hello SVG
import pygal
bar_chart = pygal.Bar()
bar_chart.add('linuxidc', [0, 1, 1, 5, 6, 8, 13, 22, 35, 55])
bar_chart.render_to_file('linuxidc.com.svg')