Reduces the colour count of an image and then overlays those colours as cubes onto the image

colourchart.sh

#!/bin/bash

#Reduces the colour count of an image and then overlays those colours as cubes onto the image
#Developed for Post-Modern Plant Life: An [RHP] CDRs Artist Laboratory https://www.facebook.com/events/1452413868331145/

for file in *.JPG
do

	colors=$1

	#line number in colours.txt
	lineno=1

	rm colors.txt

	ypos=20

	#get path of file
	path=$( readlink -f "$( dirname "$file" )" )

	#get filename minus extension
	file=$(basename "$file")
	filename="${file%.*}"

	#get extension
	extension="${file##*.}"

	#convert image to a smallerr scale
	convert "$file" -scale 500x "$path"/"$filename"_small."$extension"

	#get histogram featuring n colours and save it to colours.txt
	convert "$path"/"$filename"_small."$extension" -colors "$colors" -depth 8 -format "%c" histogram:info: | head -n 18 | cut -d# -f2 | cut -ds -f-1 > colors.txt

	while [ $lineno -le $colors ]
	do

		convert "$path"/"$filename"_small."$extension" -fill "#""$(sed -n "$lineno{p}" colors.txt);" -stroke "#FFFFFF" -draw "rectangle 20,$ypos 40,$(($ypos + 20))" "$path"/"$filename"_small."$extension"

		lineno=$(($lineno + 1))
		ypos=$(($ypos + 20))

	done

done