In this blog post, the described data feed is for the exported CSV data files or for direct usage of the binary (.fd or .min) which are of course static
For a real-time feed and trading broker for VisualChart you may want to look into:
Docs - Live Data Feeds and Live Trading / VisualChart
Blog - VisualChart Live Data/Trading
In the blog post introducing the feature you can see orders that were sent to VisualChart over the COM interface.
To take into account:
Test a lot. The code may contain bugs, your code may contain bugs and even VisualChart may contain bugs.
You need the python comtypes packaged detailed in the documentation. The Pull-Request hasn't yet been integrated into the main development tree (which seems more or less stopped from a development point of view)
Suggestion: read the Docs - Quickstart Access an comparison is done several times with a Simple Moving Average
You store the created indicator in a variable: self.myvar = bt.ind.Trix(...)
You access the values: self.myvar which automates the process of doing self.myvar.lines.trix