VPython 脚本的输出是什么？为什么它会在 Chrome 中为我打开？

Question

每当我使用 vpython 库运行脚本时，可视化都会在 google chrome 选项卡中打开。

我想知道为什么会这样，以及 vpython 可视化的输出是什么让它在 Chrome 选项卡中打开。

Answer 1

好吧，如果你打开site-packages/vpython/no_notebook.py，你会看到：

import webbrowser as _webbrowser

就是这样。

在后台，它在“无 jupyter 笔记本模式”下所做的是启动一个线程化的本地 HTTP 服务器，该服务器提供一些 javascript，然后在您的网络浏览器中打开一个页面以连接到该服务器。其余的只是服务器和客户端之间的数据交换，就像任何其他 Web 应用程序一样。

更详细的数据交换说明见site-packages/vpython/vpython.py：

# Now there is no threading in Jupyter VPython. Data is sent to the
# browser from the trigger() function, which is called by a
# canvas_update event sent to Python from the browser (glowcomm.js), currently
# every 33 milliseconds. When trigger() is called, it immediately signals
# the browser to set a timeout of 33 ms to send another signal to Python.
# Note that a typical VPython program starts out by creating objects (constructors) and
# specifying their attributes. The 33 ms signal from the browser is adequate to ensure
# prompt data transmissions to the browser.

# The situation with non-notebook use is similar, but the http server is threaded,
# in order to serve glowcomm.html, jpg texture files, and font files, and the
# websocket is also threaded.

# In both the notebook and non-notebook cases output is buffered in baseObj.updates
# and sent as a block to the browser at render times.

老实说，我不认为 vpython 的模型是一个好的 API 模型（一方面，在普通的交互式 shell 中使用它很尴尬），但我想它可以工作。