This video covers the basics of vector graphics:
How vector images are defined.
Filling vector shapes.

Source code: https://github.com/leddoo/eduvector...

Some next steps:
Write a faster rasterizer by reusing previous pixel winding calculations.
Fill pixels in an image instead of printing to the console.
Antialiasing & more robust maths.
Bezier curves & flattening them to line segments.
Stroke paths by "offsetting" them.