Interpolate from one color to another

Question

I am trying to get an interpolation of one color to another shade of the same color. (for eg: sky blue to dark blue and then back).

I stumbled upon some code that could be used if the range was from 0-255 or 0-1. However, in my case, I have the RGB codes for Color1 and Color2, and want the rotation to occur.

Color 1: 151,206,255
Color 2: 114,127,157

Any ideas how to go about this?

Answer 1

I suggest you convert RGB to HSV, then adjust its components, then convert back to RGB.

Wikipedia has an article about it, and it's been discussed here before:

HSL to RGB color conversion

Algorithm to convert RGB to HSV and HSV to RGB in range 0-255 for both

Also many frameworks have conversion functions, for example Qt has QColor class.

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But the question was about the actual interpolation... here's a trivial interpolation function:

// 0 <= stepNumber <= lastStepNumber
int interpolate(int startValue, int endValue, int stepNumber, int lastStepNumber)
{
    return (endValue - startValue) * stepNumber / lastStepNumber + startValue;
}

So call that for all color components you want to interpolate, in a loop. With RBG interpolation, you need to interpolate every component, in some other color space you may need to interpolate just one.