问如何获得实心背景色和半透明叠加色的有效效果(6位十六进制值)？

EN

result_red =  fg_red * α_fg + bg_red * (1 - α_fg)
result_blue =  fg_blue * α_fg + bg_blue * (1 - α_fg)
result_green =  fg_green * α_fg + bg_green * (1 - α_fg)

function calcColorAverages(firstColor, secondColor){

  let newColor = [];

  for(let index in firstColor){
    let colorOne = firstColor[index]
    let colorTwo = secondColor[index]

    let average = Math.round((colorOne + colorTwo) / 2);

    newColor[index] = average;

  }

  return newColor

}

let red = [255, 0, 0]
let blue = [0, 0, 255]

let purple = calcColorAverages(red, blue)

console.log(purple) //128, 0, 128