python graphviz的使用(画图工具)
一、graphviz安装及配置
graphviz实际上是一个绘图工具，可以根据dot脚本画出树形图等。
1、windows安装
- 安装graphviz软件：https://graphviz.gitlab.io/_pages/Download/Download_windows.html
- 配置环境变量：把bin文件夹的路径加入到环境变量path里
- 安装python的graphviz模块：pip install graphviz
2、linux centos7安装
- yum下载graphviz软件：yum -y install graphviz
- 安装python的graphviz模块：pip install graphviz
- 测试：which dot
二、graphviz的使用
graphviz 有两种图，一种是无向图 graph ，边用 -- 连接，一种是有向图 digraph ，边用 -> 连接
1、初步认识
from graphviz import Digraph # 实例化一个Digraph对象(有向图)，name:生成的图片的图片名，format:生成的图片格式 dot = Digraph(name="MyPicture", comment="the test", format="png") # 生成图片节点，name：这个节点对象的名称，label:节点名,color：画节点的线的颜色 dot.node(name='a', label='Ming', color='green') dot.node(name='b', label='Hong', color='yellow') dot.node(name='c', label='Dong') # 在节点之间画线，label：线上显示的文本,color:线的颜色 dot.edge('a', 'b', label="ab\na-b", color='red') # 一次性画多条线，c到b的线，a到c的线 dot.edges(['cb', 'ac']) # 打印生成的源代码 print(dot.source) # 画图，filename:图片的名称，若无filename，则使用Digraph对象的name，默认会有gv后缀 # directory:图片保存的路径，默认是在当前路径下保存 dot.view(filename="mypicture", directory="D:\MyTest") # 跟view一样的用法(render跟view选择一个即可)，一般用render生成图片，不使用view=True,view=True用在调试的时候 dot.render(filename='MyPicture', directory="D:\MyTest",view=True)
使用node()和edge()或edges()方法将节点和边添加到图形对象：
- Digraph()：实例化一个图形对象
- node()：方法第一个参数是name，第二个参数是label，即node画节点
edges()：方法可以一次添加多个边, 每个边用字符串表示, 比如cb表示从 c 到 b 的边，即edges画边edge()：方法一次添加一个边- view()：把图形画出来，并自动显示图片(弹出来),一般使用view()进行调试
- render()：把图形画出来，一般使用render保存图片的时候，view=False(不弹出图片)
调试推荐使用 view()
保存图片推荐使用 render(view=False)
2、字体乱码
中文的label默认是无法正确显示在图中的, 因为默认的字体并不支持中文, 需要我们为node设置字体。
# 有些字体是需要下载的，默认使用Microsoft YaHei就好 0、字体样式微软雅黑：Microsoft YaHei 1、字体样式华文黑体：STHeiti 2、字体样式华文楷体：STKaiti 3、字体样式华文宋体：STSong 4、字体样式华文仿宋：STFangsong 5、字体样式黑体：SimHei 6、字体样式宋体：SimSun 7、字体样式新宋体：NSimSun 8、字体样式仿宋：FangSong 9、字体样式楷体：KaiTi 10、字体样式仿宋_GB2312：FangSong_GB2312 11、字体样式楷体_GB2312：KaiTi_GB2312 12、字体样式微软正黑体：Microsoft JhengHei 13、字体样式微软雅黑体：Microsoft YaHei 14、字体样式隶书：LiSu 15、字体样式幼圆：YouYuan 16、字体样式华文细黑：STXihei 17、字体样式华文楷体：STKaiti 18、字体样式华文宋体：STSong 19、字体样式华文中宋：STZhongsong 20、字体样式华文仿宋：STFangsong 21、字体样式方正舒体：FZShuTi 22、字体样式方正姚体：FZYaoti 23、字体样式华文彩云：STCaiyun 24、字体样式华文琥珀：STHupo 25、字体样式华文隶书：STLiti 26、字体样式华文行楷：STXingkai 27、字体样式华文新魏：STXinwei
from graphviz import Digraph dot = Digraph(name="MyPicture", format="png") dot.node(name="A", label="老师", fontname="Microsoft YaHei") dot.node('B', '学生', fontname="Microsoft YaHei") dot.edge("A", "B", label="教学", fontname="Microsoft YaHei") dot.render(filename="MyPicture")
3、无向图
用法跟有向图一样
from graphviz import Graph # 无向图 dot = Graph(name="MyPicture", format="png") dot.node("People") dot.node("Home") dot.edge("People", "Home") dot.view(filename="MyPicture")
三、属性(样式)说明
node节点属性如下
| Name | Default | Values |
|---|---|---|
| color | black | node shape color |
| comment | any string (format-dependent) | |
| distortion | 0.0 | node distortion for shape=polygon |
| fillcolor | lightgrey/black | node fill color |
| fixedsize | false | label text has no affect on node size |
| fontcolor | black | type face color |
| fontname | Times-Roman | font family |
| fontsize | 14 | point size of label |
| group | name of node’s group | |
| height | .5 | height in inches |
| label | node name | any string |
| layer | overlay range | all, id or id:id |
| orientation | 0.0 | node rotation angle |
| peripheries | shape-dependent | number of node boundaries |
| regular | false | force polygon to be regular |
| shape | ellipse | node shape; see Section 2.1 and Appendix E |
| shapefile | external EPSF or SVG custom shape file | |
| sides | 4 | number of sides for shape=polygon |
| skew | 0.0 | skewing of node for shape=polygon |
| style | graphics options, e.g. bold, dotted, filled; cf. Section 2.3 | |
| URL | URL associated with node (format-dependent) | |
| width | .75 | width in inches |
| z | 0.0 | z coordinate for VRML output |
edge边框属性
| Name | Default | Values |
|---|---|---|
| arrowhead | normal | style of arrowhead at head end |
| arrowsize | 1.0 | scaling factor for arrowheads |
| arrowtail | normal | style of arrowhead at tail end |
| color | black | edge stroke color |
| comment | any string (format-dependent) | |
| constraint | true | use edge to affect node ranking |
| decorate | if set, draws a line connecting labels with their edges | |
| dir | forward | forward, back, both, or none |
| fontcolor | black | type face color |
| fontname | Times-Roman | font family |
| fontsize | 14 | point size of label |
| headlabel | label placed near head of edge | |
| headport | n,ne,e,se,s,sw,w,nw | |
| headURL | URL attached to head label if output format is ismap | |
| label | edge label | |
| labelangle | -25.0 | angle in degrees which head or tail label is rotated off edge |
| labeldistance | 1.0 | scaling factor for distance of head or tail label from node |
| labelfloat | false | lessen constraints on edge label placement |
| labelfontcolor | black | type face color for head and tail labels |
| labelfontname | Times-Roman | font family for head and tail labels |
| labelfontsize | 14 | point size for head and tail labels |
| layer | overlay range | all, id or id:id |
| lhead | name of cluster to use as head of edge | |
| ltail | name of cluster to use as tail of edge | |
| minlen | 1 | minimum rank distance between head and tail |
| samehead | tag for head node; edge heads with the same tag are | |
| sametail | merged onto the same port | |
| style | tag for tail node; edge tails with the same tag are merged onto the same port | |
| taillabel | graphics options, e.g. bold, dotted, filled; cf. Section 2.3 | |
| tailport | label placed near tail of edge n,ne,e,se,s,sw,w,nw | |
| tailURL | URL attached to tail label if output format is ismap | |
| weight | 1 | integer cost of stretching an edge |
Digraph图属性如下
| Name | Default | Values |
|---|---|---|
| bgcolor | background color for drawing, plus initial fill color | |
| center | false | center drawing on page |
| clusterrank | local | may be global or none |
| color | black | for clusters, outline color, and fill color if fillcolor not defined |
| comment | any string (format-dependent) | |
| compound | false | allow edges between clusters |
| concentrate | false | enables edge concentrators |
| fillcolor | black | cluster fill color |
| fontcolor | black | type face color |
| fontname | Times-Roman | font family |
| fontpath | list of directories to search for fonts | |
| fontsize | 14 | point size of label |
| label | any string | |
| labeljust | centered | ”l” and ”r” for left- and right-justified cluster labels, respectively |
| labelloc | top | ”t” and ”b” for top- and bottom-justified cluster labels, respectively |
| layers | id:id:id… | |
| margin | .5 | margin included in page, inches |
| mclimit | 1.0 | scale factor for mincross iterations |
| nodesep | .25 | separation between nodes, in inches. |
| nslimit | if set to f, bounds network simplex iterations by (f)(number of nodes) when setting x-coordinates | |
| nslimit1 | if set to f, bounds network simplex iterations by (f)(number of nodes) when ranking nodes | |
| ordering | if out out edge order is preserved | |
| orientation | portrait | if rotate is not used and the value is landscape, use landscape orientation |
| page | unit of pagination, e.g. “8.5,11” | |
| pagedir | BL | traversal order of pages |
| quantum | if quantum ¿ 0.0, node label dimensions will be rounded to integral multiples of quantum | |
| rank | same, min, max, source or sink | |
| rankdir | TB | LR (left to right) or TB (top to bottom) |
| ranksep | .75 | separation between ranks, in inches. |
| ratio | approximate aspect ratio desired, fill or auto | |
| remincross | if true and there are multiple clusters, re-run crossing minimization | |
| rotate | If 90, set orientation to landscape | |
| samplepoints | 8 | number of points used to represent ellipses and circles on output (cf. Appendix C |
| searchsize | 30 | maximum edges with negative cut values to check when looking for a minimum one during network simplex |
| size | maximum drawing size, in inches | |
| style | graphics options, e.g. filled for clusters | |
| URL | URL associated with graph (format-dependent) |
例子
"""使用graph_attr, node_attr, edge_attr参数, 你可以更改图中节点和边的显示样式""" from graphviz import Digraph # 可以在实例化对象的时候设置样式 dot = Digraph(name="MyPicture", node_attr={"shape": "plaintext"}, format="png") # 也可以实例化之后, 设置这些样式 dot.graph_attr['rankdir'] = 'LR' dot.edge_attr.update(arrowhead='vee', arrowsize='2') # 然后开始画图 dot.node("Dog") dot.node("Cat") dot.edge("Dog", "Cat") dot.view(filename="MyPicture")
四、官网
