python graphviz的使用(画图工具)

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参考文章1

参考文章2

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 YaHei1、字体样式华文黑体：STHeiti2、字体样式华文楷体：STKaiti3、字体样式华文宋体：STSong4、字体样式华文仿宋：STFangsong5、字体样式黑体：SimHei6、字体样式宋体：SimSun7、字体样式新宋体：NSimSun8、字体样式仿宋：FangSong9、字体样式楷体：KaiTi10、字体样式仿宋_GB2312：FangSong_GB231211、字体样式楷体_GB2312：KaiTi_GB231212、字体样式微软正黑体：Microsoft JhengHei13、字体样式微软雅黑体：Microsoft YaHei14、字体样式隶书：LiSu15、字体样式幼圆：YouYuan16、字体样式华文细黑：STXihei17、字体样式华文楷体：STKaiti18、字体样式华文宋体：STSong19、字体样式华文中宋：STZhongsong20、字体样式华文仿宋：STFangsong21、字体样式方正舒体：FZShuTi22、字体样式方正姚体：FZYaoti23、字体样式华文彩云：STCaiyun24、字体样式华文琥珀：STHupo25、字体样式华文隶书：STLiti26、字体样式华文行楷：STXingkai27、字体样式华文新魏：STXinwei

字体样式

from graphviz import Digraphdot = 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")