Agg

Anti-Grain Geometry (AGG) is an Open Source, free of charge
graphic library, written in industrially standard C++. The
terms and conditions of use AGG are described on The License
page. AGG doesn't depend on any graphic API or technology.
Basically, you can think of AGG as of a rendering engine that
produces pixel images in memory from some vectorial data. But
of course, AGG can do much more than that.