Is there an open-source geometry library?

Question

Geometry

Interested in an open source OOP library in any programming language that implements:

1. various geometric primitives - points, vectors, lines, polygons, polygons, circles, etc.
   
2. different tools for them - the intersection of primitives, union, division of polygons, matrices, etc.
   

I am writing my own library for creating simple CAD systems. But I feel like I'm reinventing the wheel.

Answer 1

Libraries for rendering vector graphics: ShivaVG, Cairo, Anti-Grain Geometry (AGG)
Software for manipulating vector objects: Inkscape , Xara LX and all sorts of open source CADs.

Answer 2

OpenGL?

Answer 3

box2d / chipmunk /etc...