Ask HN: Need C code for drawing graphic primitives to a framebuffer

I have a framebuffer that must be seen as being slow. Also the cpu accessing the fb has no cache whatsoever to accelerate the memory access. I need c code for drawing thick lines with endcaps, thick circles, thick elipsoids and thick beizier curves. I have code to do all this 1 pixel wide, but I need code to draw them with a width without plotting over and over each pixel. I already have Bresenham implementation for lines, circles, ellipsis and beizier