[-] Quaternions [X] Draw rotated pixels in src order [X] Use atan2 at beginning and end of line. Interpolation in-between values [X] Test pixel perfect 90 [ ] Fix out-of-bounds pixel set [ ] Optimization for square images? [ ] Fixed point computation? # Cache [X] Rotate per channel -> no gain [ ] Load pixels in uint64-t [ ] Cut image in tiles # Quality [X] Interpolate using SIMD, SSE (no big gain)