Whenever I run a script using the vpython library, the visualization opens in a google chrome tab.
I want to know why this is the case, and what the output of the vpython visualization is that would make it open in a Chrome tab.
Well, if you open site-packages/vpython/no_notebook.py, you will see:
import webbrowser as _webbrowser
So that's that.
Under the hood, what it does in "no jupyter notebook mode" is that it starts a threaded local HTTP server that serves up some javascript, and then open a page in your web browser to connect to that server. The rest is just exchange of data between the server and the client, like any other web application.
A more detailed explanation of the data exchange can be found in 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.
Honestly, I don't think the model of vpython is a good API model (for one thing, it's awkward to use from a normal interactive shell), but I guess it works.