color utilis

color-utils.sh

#!/usr/bin/env bash

# @author : Anthony Bourdain
# @credit : https://stackoverflow.com/a/55073732/2940319
# @usage  :
# - `rgbtohex 17 0 26` ==> 1001A
# - `rgbtohex -h 17 0 26` ==> #1001A
function rgbtohex () {
  addleadingzero () { awk '{if(length($0)<2){printf "0";} print $0;}';}
  if [[ ${1} == "-h" ]]; then
    r=${2}; g=${3}; b=${4};h='#';
  else
    r=${1}; g=${2}; b=${3};h='';
  fi
  r=$(echo "obase=16; ${r}" | bc | addleadingzero)
  g=$(echo "obase=16; ${g}" | bc | addleadingzero)
  b=$(echo "obase=16; ${b}" | bc | addleadingzero)
  echo "${h}${r}${g}${b}"
}

# @author : Anthony Bourdain
# @credit : https://stackoverflow.com/a/55073732/2940319
# @usage  :
# - `rgbto256 0 95, 135` ==> 22
function rgbto256 () {
  echo "define trunc(x){auto os;os=scale;scale=0;x/=1;scale=os;return x;};" \
    "16 + 36 * trunc(${1}/51) + 6 * trunc(${2}/51) +" \
    " trunc(${3}/51)" | bc
  # XTerm Color Number = 16 + 36 * R + 6 * G + B | 0 <= R,G,B <= 5
}

# @author : Anthony Bourdain
# @credit : https://stackoverflow.com/a/55073732/2940319
# @usage  :
# - `hexttorgb "11001A" ==> 17 0 26
# - `hexttorgb "#11001A" ==> 17 0 26
function hextorgb () {
  hexinput=$(echo "${1}" | tr '[:lower:]' '[:upper:]')           # uppercase-ing
  hexinput=$(echo "${hexinput}" | tr -d '#')                     # remove Hash if needed
  a=$(echo "${hexinput}" | cut -c-2)
  b=$(echo "${hexinput}" | cut -c3-4)
  c=$(echo "${hexinput}" | cut -c5-6)
  r=$(echo "ibase=16; ${a}" | bc)
  g=$(echo "ibase=16; ${b}" | bc)
  b=$(echo "ibase=16; ${c}" | bc)
  echo "${r} ${g} ${b}"
}

# Generates Truecolor Escape Sequences from Hex Strings. (remove '\\' to use)
# @author : Anthony Bourdain
# @credit : https://stackoverflow.com/a/55073732/2940319
# @params :
# -fg     Prints as a foreground color. (default)
# -bg     Prints as a background color.
# @usage  :
# - `trueHexPrint -fg "11001A" ==> '\e[38;2;17;0;26m'
# - `trueHexPrint -bg "11001A" ==> '\e[48;2;17;0;26m'
function trueHexPrint () {
  if [[ ${1} =~ "-fg" || ${1} =~ "-f" ]]; then
    fgbg=38; hexinput=${2};
  elif [[ ${1} =~ "-bg" || ${1} =~ "-b" ]]; then
    fgbg=48; hexinput=${2};
  else
    fgbg=38; hexinput=${1}
  fi
  hexinput=$(echo "${hexinput}" | tr '[:lower:]' '[:upper:]')  # uppercase-ing
  hexinput=$(echo "${hexinput}" | tr -d '#')                   # remove Hash if needed
  a=$(echo "${hexinput}" | cut -c-2)
  b=$(echo "${hexinput}" | cut -c3-4)
  c=$(echo "${hexinput}" | cut -c5-6)

  r=$(echo "ibase=16; ${a}" | bc)
  g=$(echo "ibase=16; ${b}" | bc)
  b=$(echo "ibase=16; ${c}" | bc)

  printf "\\\\e[%s;2;%s;%s;%sm" "${fgbg}" "${r}" "${g}" "${b}" # Remove one set of '\\' to utilize
}

# @author : Anthony Bourdain
# @credit : https://stackoverflow.com/a/55073732/2940319
function XColorTable () {
  i=16
  for ((r = 0; r <= 255; r+=40)); do                           # do tricolor
    for ((g = 0; g <= 255; g+=40)); do
      for ((b = 0; b <= 255; b+=40)); do
        hex=$(rgbtohex ${r} ${g} ${b})
        printf  "%-3s = %-18s => %b\n" "$((i++))" "rgb(${r}, ${g}, ${b})" "$(trueHexPrint "${hex}")#${hex}\e[0m"
        if ((b == 0)); then b=55; fi
      done
      if ((g == 0)); then g=55; fi
    done
    if ((r == 0)); then r=55; fi
  done
  for ((m = 8; m <= 238; m+=10)); do                           # do monochrome
    hex=$(rgbtohex ${m} ${m} ${m})
    printf "%-3s = %-18s => %b\n" "$((i++))" "rgb(${m}, ${m}, ${m})" "$(trueHexPrint "${hex}")#${hex}\x1b[0m"
  done
}

# Generates 256 Color code table with RGB and Hex values
# @author : marslo
# @usage  :
# - to show specific color(s) with parameter(s) :
#   `xCodeTable 30 40 50` ==> '30  = rgb(0, 135, 135)   => #008787\n...\n...'
# - to show all 256 colors code table without parameter :
#   `xCodeTable`
function xColorTable() {
  declare -A COLORS
  declare -i i=16

  function _prettyPrint() {
    local _r _g _b colorCode hexCode
    colorCode="$1"
    IFS=' ' read -r _r _g _b <<< "$2"; unset IFS;
    hexCode=$(rgbtohex "${_r}" "${_g}" "${_b}")
    printf "%-3s = %-18s => %b\n" "${colorCode}" "rgb(${_r}, ${_g}, ${_b})" "$(trueHexPrint "${hexCode}")#${hexCode}\x1b[0m"
  }

  for ((r = 0; r <= 255; r+=40)); do                           # do tricolor
    for ((g = 0; g <= 255; g+=40)); do
      for ((b = 0; b <= 255; b+=40)); do
        COLORS[$i]+="$r $g $b"
        (( i++ ))
        if ((b == 0)); then b=55; fi
      done
      if ((g == 0)); then g=55; fi
    done
    if ((r == 0)); then r=55; fi
  done
  for ((m = 8; m <= 238; m+=10)); do                           # do monochrome
    COLORS[$i]+="$m $m $m"
    (( i++ ))
  done

  [[ 0 -ne "$#" ]] && output=$( echo "$@" | fmt -1) || output=$(printf "%s\n" "${!COLORS[@]}" | sort -n)
  while read -r _c; do
    _prettyPrint "${_c}" "${COLORS[${_c}]}"
  done <<< "${output}"
}

# vim:tabstop=2:softtabstop=2:shiftwidth=2:expandtab:filetype=sh

demo.md

XColorTable

xColorTable ( enhanced XColorTable )