You could try the NodeBB forum software. They have different options that range from paid plans with free trial to an Open Source option. They even have free hosting for open source project communities that qualify, according to their pricing page.
I haven't tried it myself, but there's a good article describing one user's experience with it here.
You can try Syncfusion .NET Word library (Essential DocIO) to create, read, manipulate and convert Word documents programmatically without Microsoft Word or other dependencies in your machine. It offers the Word to PDF conversion ability as well.
NuGet package required: https://help.syncfusion.com/file-formats/docio/nuget-packages-required#converting-word-...
Diagram is a feature-rich JS component for visualizing, creating, and editing interactive diagrams like flow charts, organizational charts, mind maps, BPMN diagrams, and more. Its rich feature set includes built-in shapes, editing, serializing, exporting, printing, overview, data binding, and automatic layouts.
Herewith we have a created a sample to display ...
Take a look at the Curves library.
It's header only if you plan to use it in C++.
From the documentation, it gives tools to:
create exact splines of arbitrary order (that pass exactly by an arbitrary number waypoints)
Example code from the PDF documentation (sorry I had to screenshot as the PDF breaks copy/paste):