例子: 值为:rgba(194, 7, 15, 1) ,转化16进制为: #c2070f

//转化颜色
function getHexColor(color) {
  var values = color
    .replace(/rgba?\(/, '')
    .replace(/\)/, '')
    .replace(/[\s+]/g, '')
    .split(',')
  var a = parseFloat(values[3] || 1),
    r = Math.floor(a * parseInt(values[0]) + (1 - a) * 255),
    g = Math.floor(a * parseInt(values[1]) + (1 - a) * 255),
    b = Math.floor(a * parseInt(values[2]) + (1 - a) * 255)
  return '#' +
    ('0' + r.toString(16)).slice(-2) +
    ('0' + g.toString(16)).slice(-2) +
    ('0' + b.toString(16)).slice(-2)
}
getHexColor('rgba(194, 7, 15, 1) '); // #c2070f

JS rgba颜色转16进制