Convert decimal to hex https://play.golang.org/p/JxnGqpuY8P9

hex-transparency-color.go

package main

import (
	"fmt"
	"strconv"
	"strings"
)

func dec2hex(dec int) string {
	color := dec * 255 / 100
	return fmt.Sprintf("%02x", color)
}

func hex2dec(hex string) int64 {
	dec, _ := strconv.ParseInt("0x"+hex, 0, 16)
	dec = dec * 100 / 255
	return dec
}

func main() {
	for i := 0; i <= 100; i++ {
		var hexa string = strings.ToUpper(dec2hex(i))
		fmt.Printf("%d %% \t => '%s'\n", i, hexa)

		// look further use with "hex2dec"
		// Notice that the conversion from Hexa to decimal is lower than the initial value
		// due to round down
		// fmt.Printf("%d %%  to hexa \t => '%s' \t => %d \n", i, hexa, hex2dec(hexa))
	}
}

The Go playground is https://play.golang.org/p/l1JaPYFzDkI