Description of the problem are as follows:
the first color1(c1) RGB value is rgb1,
the second color2(c2) RGB value is rgb2,
How to calculate the RGB(rgb3) of the color3(c3) mixed with c1 and c2,the mixing ratio is x: y.
For example:red and green 1:1 mixture is yellow, red and black 1:1 mixture is dark red.