Bash_Scripts/Templates/Functions/RGB-Terminal-Colors.bash

#!/bin/bash

rgb() {
    # Echo a color printf to the terminal awaiting an actual echo to be colored
    # should be used with reset after coloring a string
    #
    # Positional Arguments:
    #   red <type: int> <position: 1> <required: true>
    #     - The red value from 0 to 255
    #   green <type: int> <position: 2> <required: true>
    #     - The green value from 0 to 255
    #   blue <type: int> <position: 2> <required: true>
    #     - The blue value from 0 to 255
    #
    # Usage:
    #   echo_rgb 10 80 3 && echo "hello" && reset
    #
    # POSIX Compliant:
    #   N/A
    #

    red="${1}"
    green="${2}"
    blue="${3}"

    printf "\e[0;38;2;%s;%s;%sm" "${red}" "${green}" "${blue}"
}

echo_rgb() {
    # Echo a colored string to the terminal based on rgb values
    #
    # NOTE: This function will only truly work with terminals that support TRUE COLOR, see:
    #   https://gist.github.com/XVilka/8346728
    #
    # Positional Arguments:
    #
    #   message <type: string> <position: 1> <required: true>
    #     - The message to be printed to stdout
    #   red <type: int> <position: 2> <required: true>
    #     - The red value from 0 to 255
    #   green <type: int> <position: 3> <required: true>
    #     - The green value from 0 to 255
    #   blue <type: int> <position: 4> <required: true>
    #     - The blue value from 0 to 255
    #   bg_red <type: int> <position: 5> <required: false>
    #     - The background red value from 0 to 255
    #   bg_green <type: int> <position: 6> <required: false>
    #     - The background green value from 0 to 255
    #   bg_blue <type: int> <position: 7> <required: false>
    #     - The background blue value from 0 to 255
    #
    # Usage:
    #   echo_rgb "Yep" 10 80 30
    #   echo_rgb "DESTROY MY EYES" 255 0 255  0 255 0
    #
    # POSIX Compliant:
    #   N/A
    #

    local red
    local green
    local blue
    local input

    local bg_red
    local bg_green
    local bg_blue

    input="${1}"
    red="${2}"
    green="${3}"
    blue="${4}"
    bg_red="${5}"
    bg_green="${6}"
    bg_blue="${7}"

    for num in "${@:2}"; do
        [[ ! "${num}" =~ [0-9] ]] &&
            echo "Given RGB value was not a number, received ${num}" &&
            return 1
        [[ "${num}" -gt 255 ]] &&
            echo "Given RGB value must be less than 255, received ${num}" &&
            return 1
        [[ "${num}" -lt 0 ]] &&
            echo "Given RGB value must be more than 0, received ${num}" &&
            return 1
    done

    if [ -t 1 ]; then
        if [ -n "${5}" ]; then
            [[ -z "${6}" ]] && echo "A value must be passed for bg_green" && return 1
            [[ -z "${7}" ]] && echo "A value must be passed for bg_blue" && return 1
            printf "\033[38;2;%s;%s;%s;48;2;%s;%s;%sm%s\033[m\n" \
                "${red}" "${green}" "${blue}" "${bg_red}" "${bg_green}" "${bg_blue}" "${input}"
        else
            printf "\033[0;38;2;%s;%s;%sm%s\033[m\n" "${red}" "${green}" "${blue}" "${input}"
        fi
    else
        printf "%s\n" "${input}"
    fi
    return 0
}

reset() {
    # Reset colors in the terminal to default
    #
    # Usage:
    #   reset
    #
    # POSIX Compliant:
    #   N/A
    #

    printf "\e[m\n"
}