notes/scripts/rgb2hsl.sh
2022-12-22 20:32:47 -08:00

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#!/usr/bin/env bash
# Prompt user for RGB or RGBA values
echo -n "Enter RGB or RGBA values: "
read r g b a
# Convert RGB to HSL
r=$((r/255))
g=$((g/255))
b=$((b/255))
max=${r}
min=${r}
if [[ ${g} -gt ${max} ]]; then max=${g}; fi
if [[ ${b} -gt ${max} ]]; then max=${b}; fi
if [[ ${g} -lt ${min} ]]; then min=${g}; fi
if [[ ${b} -lt ${min} ]]; then min=${b}; fi
l=$(((max+min)/2))
if [[ ${max} == ${min} ]]; then
h=0
s=0
else
d=$((max-min))
if [[ $(echo "${l} > 0.5" | bc -l) -eq 1 ]]; then
s=$((d/(2-max-min)))
else
s=$((d/(max+min)))
fi
case ${max} in
${r}) h=$(((g-b)/d))
if [[ ${h} -lt 0 ]]; then h=$((h+6)); fi
;;
${g}) h=$((2+(b-r)/d))
;;
${b}) h=$((4+(r-g)/d))
;;
esac
h=$((h*60))
fi
# Output HSLA values
echo ${h} ${s} ${l} ${a}