在 sphinx-gallery 中捕获 Graphviz 图形

Question

我正在生成带有 sphinx-gallery, and would like to embed graphviz 输出的示例，类似于捕获 matplotlib 数字的方式。

下面是我当前进度的屏幕截图。请注意，捕获的 Out 显示了数字的字符串或字节表示形式。

我希望 Out 成为 image/svg。

我调查了以下内容：

graphviz 可以 export SVG for Jupyter notebooks through a private _repr_svg_() method，但 sphinx-gallery 将其解释为字符串。
sphinx-gallery 有 experimental support for "Custom Image Scrapers"，但我想在我的示例中避免胶水代码，其中我“ 写入图像文件，然后将它们读回生成的 html ."
graphviz 文档是如何做到这一点的？ By generating .png figures ahead of time and embedding them with .. image:: directives.

更新 (2020-11-26)：添加一个 _repr_html_ 包装 graphviz 的 _repr_svg_ 方法似乎是最短路线。我实现了一个粗略的版本：

这是我已经尝试过的代码：

# File: examples/plot_graphviz_svg.py

"""
==================================================
Capturing the output of Graphviz in Sphinx-Gallery
==================================================

This is a quick demo trying to capture the SVG output
from Graphviz and embed it in a Sphinx Gallery.
"""

import graphviz

dig = graphviz.Digraph('G', filename='hello.gv')
dig.edge('hello', 'world')
dig._repr_svg_()

# %%
# The first output should be above, the next should appear below:

dig2 = graphviz.Digraph('G2', filename="hello2.gv")
dig2.edge('world', 'hello')
dig.pipe()

最小 sphinx conf.py:

project = 'sphinx-graphviz-svg'
copyright = '2020, Alexander L. Hayes'
author = 'Alexander L. Hayes'
release = '0.0.1'
extensions = [
    'sphinx_gallery.gen_gallery',
]
templates_path = ['_templates']
exclude_patterns = []
html_theme = 'alabaster'
html_static_path = ['_static']

还有一个最小的 index.rst 链接到示例库：

Welcome to sphinx-graphviz-svg's documentation!
===============================================

.. toctree::
   :hidden:
   :maxdepth: 1
   :caption: Example Gallery

   auto_examples/index

Answer 1

我在 graphviz repository here: #121 中有一个开放的拉取请求。

如果您不耐烦，这里有一种使用相当小的包装纸的可能性：

class PlotGraphviz:

    def __init__(self, dot_string):
        self.dot_string = dot_string

    def _repr_html_(self):
        return graphviz.Source(self.dot_string)._repr_svg_()

如果将来合并拉取请求，这会更清晰。

现在：

# File: examples/plot_graphviz_svg.py

"""
==================================================
Capturing the output of Graphviz in Sphinx-Gallery
==================================================

This is a quick demo trying to capture the SVG output
from Graphviz and embed it in a Sphinx Gallery.
"""

import graphviz

class PlotGraphviz:

    def __init__(self, dot_string):
        self.dot_string = dot_string

    def _repr_html_(self):
        return graphviz.Source(self.dot_string)._repr_svg_()

# %%
# First example:

dig = graphviz.Digraph()
dig.edge("hello", "world")
PlotGraphviz(str(dig))

# %%
# More info ...

渲染到:

在 sphinx-gallery 中捕获 Graphviz 图形

Capturing Graphviz figures in sphinx-gallery

python

graphviz

python-3.x

python-sphinx