The new version of Keep Calm contains an awesome color picker shown in the video above. This is GPU accelerated with OpenGL, accessible and now open source on GitHub. I had hoped to use an existing open source project, however most pickers that I could find either had to use an external image, were limited to only a subset of all 24-bit colors or generated a lot of their graphics on the CPU.

Therefore my goal was to make my rendering code incredibly efficient, and as a result it can be animated at 60fps comfortably (it barely takes a millisecond to render the whole color square, whereas other color pickers take several seconds to generate pixelated versions on the CPU).