Convert to and from 32 bit color to the Microsoft Safety Pallete (216) indexed colors.

32bit color conversion 8bit color

// Generating a CLUT of the Microsoft Safety Pallete
// https://www.gidforums.com/t-21296.html

// Microsoft Safety Pallete
// https://msdn.microsoft.com/en-us/library/bb250466(VS.85).aspx
// Convert to indexed color
int index = (color.red()/51)*36
                + (color.green()/51)*6
                + color.blue()/51
                + 20;

/////////////////////////////////////

// convert from indexed color
int r, g, b, temp;
temp = index - 20;
g = (temp%6)*51;
b = ((temp/6)%6)*51;
r = ((temp/36)%6)*51;