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5294130 Nov 11, 2013
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executable file 101 lines (91 sloc) 1.91 KB
#!/bin/bash
#
# This file echoes four gradients with 24-bit color codes
# to the terminal to demonstrate their functionality.
# The foreground escape sequence is ^[38;2;<r>;<g>;<b>m
# The background escape sequence is ^[48;2;<r>;<g>;<b>m
# <r> <g> <b> range from 0 to 255 inclusive.
# The escape sequence ^[0m returns output to default
SEPARATOR=':'
setBackgroundColor()
{
echo -en "\x1b[48${SEPARATOR}2${SEPARATOR}$1${SEPARATOR}$2${SEPARATOR}$3""m"
}
resetOutput()
{
echo -en "\x1b[0m\n"
}
# Gives a color $1/255 % along HSV
# Who knows what happens when $1 is outside 0-255
# Echoes "$red $green $blue" where
# $red $green and $blue are integers
# ranging between 0 and 255 inclusive
rainbowColor()
{
let h=$1/43
let f=$1-43*$h
let t=$f*255/43
let q=255-t
if [ $h -eq 0 ]
then
echo "255 $t 0"
elif [ $h -eq 1 ]
then
echo "$q 255 0"
elif [ $h -eq 2 ]
then
echo "0 255 $t"
elif [ $h -eq 3 ]
then
echo "0 $q 255"
elif [ $h -eq 4 ]
then
echo "$t 0 255"
elif [ $h -eq 5 ]
then
echo "255 0 $q"
else
# execution should never reach here
echo "0 0 0"
fi
}
for i in `seq 0 127`; do
setBackgroundColor $i 0 0
echo -en " "
done
resetOutput
for i in `seq 255 128`; do
setBackgroundColor $i 0 0
echo -en " "
done
resetOutput
for i in `seq 0 127`; do
setBackgroundColor 0 $i 0
echo -n " "
done
resetOutput
for i in `seq 255 128`; do
setBackgroundColor 0 $i 0
echo -n " "
done
resetOutput
for i in `seq 0 127`; do
setBackgroundColor 0 0 $i
echo -n " "
done
resetOutput
for i in `seq 255 128`; do
setBackgroundColor 0 0 $i
echo -n " "
done
resetOutput
for i in `seq 0 127`; do
setBackgroundColor `rainbowColor $i`
echo -n " "
done
resetOutput
for i in `seq 255 128`; do
setBackgroundColor `rainbowColor $i`
echo -n " "
done
resetOutput