luminance

#!/bin/bash

brightness=128
contrast=71

echo "Luminance Controller for SAA7113 Video Input Processor"
echo "Default Values:"
echo "Brightness: 128 Contrast: 71"
echo "Use the D and C keys to raise and lower contrast;"
echo "G and B raise and lower brightness"
echo "Press Q key to exit"

while true; do
    read -rsn1 input
    if [ "$input" = "g" ]; then 
        if [ $brightness -lt "255" ]; then
	    ((brightness++))
	fi
        echo "Brightness Up:" $brightness
        i2cset -y 1 0x25 0x0a $brightness
    fi
    if [ "$input" = "b" ]; then
        if [ $brightness -gt "0" ]; then
            ((brightness--))
        fi
        echo "Brightness Down:" $brightness
        i2cset -y 1 0x25 0x0a $brightness
    fi
    if [ "$input" = "d" ]; then
        if [ $contrast -lt "255" ]; then
            ((contrast++))
        fi
        echo "Contrast Up:" $contrast
        i2cset -y 1 0x25 0x0b $contrast
    fi
    if [ "$input" = "c" ]; then
        if [ $contrast -gt "0" ]; then
            ((contrast--))
        fi
        echo "Contrast Down:" $contrast
        i2cset -y 1 0x25 0x0b $contrast
    fi

    if [ "$input" = "q" ]; then
        echo "Brightness:" $brightness "Contrast" $contrast
	exit 
    fi
done