Looking for color picker similar to the one in Tumblr

Is anyone aware of an open source color picker such as the one in Tumblr?

It has a predefined set of colors at top, which open more shades of that color when clicked. It also has a free range color picker option. I know there are plenty of color pickers that can display a palette as well as have the free form selection, but I haven't found any that behave exactly like this: