title: What is a good, optimized C/C++ algorithm for converting a 24-bit bitmap to 16-bit with dithering?
body: <p>I've been looking for an optimized (i.e., quick) algorithm that converts a 24-bit RGB bitmap to a 16-bit (RGB565) bitmap using dithering. I'm looking for something in C/C++ where I can actually control how the dithering is applied. GDI+ seems to provide some methods, but I can't tell if they dither or not. And, if they do dither, what mechanism are they using (Floyd-Steinberg?)</p>
  
  <p>Does anyone have a good example of bitmap color-depth conversion with dithering?</p>