Formula for calculating color?

Question

Design

The input is an array of 7 colors of the rainbow.
How can you calculate the proportions of mixing colors to get a given one? For example, I want to get the color #617730, I need to calculate which of the 7 colors of the rainbow and in what proportions I need to mix.

Answer 1

to get any color, it is enough to have 3 RGB colors.
so
#617730 = #610000 + #007700 + #000030

Answer 2

I think this article will help you

Answer 3

The task is formulated too generally, you need to look at the specifics and details.
Depending on them, it can turn out to be both elementary (like Yuri 's answer ), and very complex things that go into science to the very top.

Answer 4

R = R1 + (R2 - R1) * Blend / 255;
G = G1 + (G2 - G1) * Blend / 255;
B = B1 + (B2 - B1) * Blend / 255;
where Blend = 0..255 as transition values ​​from one color to another, 127 - mixed in half...