As LanX says, there's all kinds of colour wheels. This page has an interesting interactive colour wheel that, when played around with, illustrates how tricky your problem is. I'm guessing that some maths to convert RGB values into angular values based on proportion would be a starting point but you then have the white/black question to resolve, which adds the third dimension.

Cheers,

JohnGG

In reply to Re: Ordering Colours Problem by johngg
in thread Ordering Colours Problem by merrymonk

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