Bourne-Again shell script, ASCII text executable
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#!/usr/bin/env bash
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#set -x
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mix_channel() {
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value1=$(printf '%03d' 0x${1})
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value2=$(printf '%03d' 0x${2})
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ratio=${3}
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result=$(echo "scale=0; (${value1} * 100 * ${ratio} + ${value2} * 100 * (1 - ${ratio}))/100" | bc)
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if [[ ${result} -lt 0 ]] ; then
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result=0
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elif [[ ${result} -gt 255 ]] ; then
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result=255
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fi
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echo "${result}"
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}
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mix() {
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hexinput1=$(echo $1 | tr '[:lower:]' '[:upper:]')
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hexinput2=$(echo $2 | tr '[:lower:]' '[:upper:]')
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ratio=${3-0.5}
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a=$(echo $hexinput1 | cut -c-2)
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b=$(echo $hexinput1 | cut -c3-4)
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c=$(echo $hexinput1 | cut -c5-6)
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d=$(echo $hexinput2 | cut -c-2)
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e=$(echo $hexinput2 | cut -c3-4)
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f=$(echo $hexinput2 | cut -c5-6)
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r=$(mix_channel ${a} ${d} ${ratio})
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g=$(mix_channel ${b} ${e} ${ratio})
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b=$(mix_channel ${c} ${f} ${ratio})
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printf '%02x%02x%02x\n' ${r} ${g} ${b}
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}
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mix $@
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