在pygraph中设置图形属性

Question

我在pygraph的文档中找到了如何更改节点和边的属性，但是没有找到关于如何更改图形属性的帮助。

我尝试了几次，但都没成功：

gr = graph()
gr.__setattr__('aspect',2)

你有什么建议吗？

谢谢！

[更新] 我还尝试了：

gr = graph()
gr.__setattr__('rotate',90)
gr.rotate = 90
gr.color = 'red'
setattr(gr,'bgcolor','red')

[更新 2] 网站上的示例代码，展示了不同的想法来更改属性：

#!/usr/bin/env python

# Copyright (c) 2007-2008 Pedro Matiello <pmatiello@gmail.com>
# License: MIT (see COPYING file)

# Import graphviz
import sys
sys.path.append('..')
sys.path.append('/usr/lib/graphviz/python/')
sys.path.append('/usr/lib64/graphviz/python/')
import gv

# Import pygraph
from pygraph.classes.graph import graph
from pygraph.classes.digraph import digraph
from pygraph.algorithms.searching import breadth_first_search
from pygraph.readwrite.dot import write

# Graph creation
gr = graph()

gr.__setattr__('rotate',90)
gr.rotate = 90
gr.color = 'red'
setattr(gr,'bgcolor','red')

# Add nodes and edges
gr.add_nodes(["Portugal","Spain","France","Germany","Belgium","Netherlands","Italy"])
gr.add_nodes(["Switzerland","Austria","Denmark","Poland","Czech Republic","Slovakia","Hungary"])
gr.add_nodes(["England","Ireland","Scotland","Wales"])

gr.add_edge(("Portugal", "Spain"))
gr.add_edge(("Spain","France"))
gr.add_edge(("France","Belgium"))
gr.add_edge(("France","Germany"))
gr.add_edge(("France","Italy"))
gr.add_edge(("Belgium","Netherlands"))
gr.add_edge(("Germany","Belgium"))
gr.add_edge(("Germany","Netherlands"))
gr.add_edge(("England","Wales"))
gr.add_edge(("England","Scotland"))
gr.add_edge(("Scotland","Wales"))
gr.add_edge(("Switzerland","Austria"))
gr.add_edge(("Switzerland","Germany"))
gr.add_edge(("Switzerland","France"))
gr.add_edge(("Switzerland","Italy"))
gr.add_edge(("Austria","Germany"))
gr.add_edge(("Austria","Italy"))
gr.add_edge(("Austria","Czech Republic"))
gr.add_edge(("Austria","Slovakia"))
gr.add_edge(("Austria","Hungary"))
gr.add_edge(("Denmark","Germany"))
gr.add_edge(("Poland","Czech Republic"))
gr.add_edge(("Poland","Slovakia"))
gr.add_edge(("Poland","Germany"))
gr.add_edge(("Czech Republic","Slovakia"))
gr.add_edge(("Czech Republic","Germany"))
gr.add_edge(("Slovakia","Hungary"))

# Draw as PNG
dot = write(gr)
gvv = gv.readstring(dot)
gv.layout(gvv,'dot')
gv.render(gvv,'png','europe.png')

Answer 1

我对pygraph不太了解，但我觉得在Python中设置属性的方法是这样的：

setattr(object, attr, value)
setattr(gr, 'aspect', 2)

我的意思是，你试过用gr.aspect = 2对吧？

Answer 2

看起来你可以用 gv.setv() 来设置图形的属性。

import gv
g = gv.digraph('19261920')
gv.setv(g, 'overlap', 'compress')

我是在查看 gv.py 的接口定义文件，路径是 /usr/include/graphviz/gv.i 时发现了 gv.setv()。

在网上搜索 "import gv" overlap setv，我找到了这篇旧帖子，里面展示了如何使用 gv.setv()。

我还找到了一份PDF格式的gv_python手册，里面有关于 setv 的更多文档。

为了这么简单的事情，真是费了不少功夫呢，对吧？

Answer 3

我自己做了一些研究，发现pygraphviz正好提供了我需要的功能。这里有一个使用pygraphviz的pygraph示例，它可以接受一些属性。而且这个示例更简洁，因为如果所有节点之间都有连接，就不需要单独指定每个节点。

#!/usr/bin/env python

# Copyright (c) 2007-2008 Pedro Matiello <pmatiello@gmail.com>
# License: MIT (see COPYING file)

# Import pygraphviz
import pygraphviz as pgv

# Graph creation and setting of attributes
gr = pgv.AGraph(rotate='90',bgcolor='lightgray')

# Add nodes and edges
gr.add_edge(("Portugal", "Spain"))
gr.add_edge(("Spain","France"))
gr.add_edge(("France","Belgium"))
gr.add_edge(("France","Germany"))
gr.add_edge(("France","Italy"))
gr.add_edge(("Belgium","Netherlands"))
gr.add_edge(("Germany","Belgium"))
gr.add_edge(("Germany","Netherlands"))
gr.add_edge(("England","Wales"))
gr.add_edge(("England","Scotland"))
gr.add_edge(("Scotland","Wales"))
gr.add_edge(("Switzerland","Austria"))
gr.add_edge(("Switzerland","Germany"))
gr.add_edge(("Switzerland","France"))
gr.add_edge(("Switzerland","Italy"))
gr.add_edge(("Austria","Germany"))
gr.add_edge(("Austria","Italy"))
gr.add_edge(("Austria","Czech Republic"))
gr.add_edge(("Austria","Slovakia"))
gr.add_edge(("Austria","Hungary"))
gr.add_edge(("Denmark","Germany"))
gr.add_edge(("Poland","Czech Republic"))
gr.add_edge(("Poland","Slovakia"))
gr.add_edge(("Poland","Germany"))
gr.add_edge(("Czech Republic","Slovakia"))
gr.add_edge(("Czech Republic","Germany"))
gr.add_edge(("Slovakia","Hungary"))

# Draw as PNG
gr.layout(prog='dot')
gr.draw('europe.png')