A short overview on parametric vector design.
Metafont is a Touring complete programming language with focus on typedesign. The concept is based on strokes and they can be adjusted to not only have letters looking like written with broad edge pen but with a typset character.
A outline based drawing program based on Cubic Splines
kalliculator.com
Application to generate digital representations of a variable and flexible broad edge pen. The with and the angel of each stroke can be modified.
aprt.us
A full parametric graphic design «constructor». The included constraint solver helps to define relations between visual representation and data. Highly inspired by Bret Victor.
A parametric glyph in motion by Prototypo
A web-based editor for parametric typefaces. The editor allows to modify but not to create three different parametric typefaces. The .ptf-format (parametric typeface) is is very advanced and allows for complex but free font models.
prototypo-builder is a new Project to generate the .ptf-Files in a Browser.
Metapolator is a young project and has a radical domain specific selector/programming language to transform and generate shapes and points. There are some GUI-Elements but that's more to controll a final typedesign and not to support a typedesigner
Programming Libs are most of the time spline based drawing abstractions in code. Sometimes they have clearly the focus of typedesing, sometimes they have mor a general outline-based approach.
In 2006 Remo Caminada and Ludovic Varone developed (in Flash) for their Diploma at the Zurich University of the Arts a type generator based on a math based model. They won the following awards with it:
Fix my mistakes on GitHub