Gradient color utils

colors.kt

fun interpColor(@FloatRange(from = 0.0, to = 1.0) unit: Float, colors: IntArray): Int {
    if (unit <= 0) return colors[0]
    if (unit >= 1) return colors[colors.size - 1]

    var p = unit * (colors.size - 1)
    val i = p.toInt()
    // take fractional part
    p -= i

    val c0 = colors[i]
    val c1 = colors[i + 1]
    // Calculates each channel separately
    val a = avg(alpha(c0), alpha(c1), p)
    val r = avg(red(c0), red(c1), p)
    val g = avg(green(c0), green(c1), p)
    val b = avg(blue(c0), blue(c1), p)

    return Color.argb(a, r, g, b)
}

fun avg(s: Int, e: Int, @FloatRange(from = 0.0, to = 1.0) p: Float) 
    = s + round(p * (e - s))

Original source could be found here https://github.com/stepango/kopi