Calculate color HEX having 2 colors and percent/position

Question

Is it possible to calculate a color in a middle of a gradient?

var color1 = \'FF0000\';
var color2 = \'00FF00\';

// 50% between the two colors, should retur         


        

Answer 1

An ES6 version with comprehensions:

function interpolateColor(c0, c1, f){
    c0 = c0.match(/.{1,2}/g).map((oct)=>parseInt(oct, 16) * (1-f))
    c1 = c1.match(/.{1,2}/g).map((oct)=>parseInt(oct, 16) * f)
    let ci = [0,1,2].map(i => Math.min(Math.round(c0[i]+c1[i]), 255))
    return ci.reduce((a,v) => ((a << 8) + v), 0).toString(16).padStart(6, "0")
}

As in the accepted answer, c0,c1 are color codes (without the leading #) and f is "progress" between the two values. (At f=0 this ends up returning c0, at f=1 this returns c1).

• The first two lines convert the color codes into arrays of scaled integers
• The third line:
  • "zips" the two integer arrays
  • sums the corresponding values
  • rounds the sum and clamps it to 0-255
• The fourth line:
  • converts the integer array into a single integer (reduce and bitshifting)
  • converts the integer into its hexadecimal string form
  • ensures the resulting string is 6 characters long and returns it