The CRT X-Y Library (libcrtxy) allows you to write vector-based video games (like Asteroids, Lunar Lander, and Battlezone from the 1970s and 80s). The end-user (and/or packager of your software) determines how lines are rendered, depending on the capabilities of their system. This choice includes anti-aliasing, alpha blending, blurring, and even the display size and depth. Fixed-point math is used, and sine and cosine trigonometric functions (using look-up tables) are provided. The library is based on libSDL and uses SDL as the video backend.