Color space

whether ROOT support CMYK mode?

The colors in ROOT are handled by the the class TColor. This class have the RGB and the HLS color systems. It provides all the functions to convert a color from a system into an other. We can surely add the converters to CMY. Is that what you are looking for ?

Thank you for your help. Should I add the converter myself or Root includes the functions. If it has the function, how I can realize it? what HLS means?
Thanks in advance.

You can see the list of the available functions here

I do not know which function you need. Very likeley RGB to CMY and vice versa ? If you know how to write them and would like to do it, you can, and we will include them in this class.

RGB and CNY are very similar. They both are based on % of colors (Red Gren Blue or Cyan Magenta Yellow) In ROOT we choose RGB be cause it is the most common one. It is not very useful to have 2 as they provide the same functionnality

On the other hand, HLS provides more flexibility. HLS means Hue Saturation Luminosity. This is a very convenient system to define continuous color pallettes.

If you tell me why and where you need CMY I might be able to help you further.