64 lines
1.7 KiB
Bash
Executable file
64 lines
1.7 KiB
Bash
Executable file
#!/bin/bash
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set -euo pipefail
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# Control screen brightness in a logarithmic fashion. Linear backlight control
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# just annoys me: I want fine-grained control over low brightnesses and quickly
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# change the value at high brightnesses.
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#
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# We assume the minimum brightness is 0 (light off) and the maximum brightness
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# is 100. This is the behaviour of
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# [acpilight](https://github.com/wavexx/acpilight/), a replacement for
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# xorg-xbacklight (which doesn't work on my laptop for some reason).
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#
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# Use `backlight.sh up` or `backlight.sh down` to increase or decrease the
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# backlight brightess. If you want to adjust the speed with which it changes,
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# adjust `change_percent` below.
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# Multiply the current brightness by this percentage. This has to be an integer
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change_percent=150
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# Don't start a new transition if the previous one isn't done yet
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pgrep -u $UID -x xbacklight >/dev/null && exit
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# Calculate new target brightness
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current_brightness=$(xbacklight -get)
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new_target() {
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echo $current_brightness >&2
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case $1 in
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up)
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if [ $current_brightness = 0 ]; then
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echo 1
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return
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fi
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target=$((current_brightness * $change_percent / 100))
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[ $target -ne $current_brightness ] || target=$((target + 1))
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;;
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down)
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if [ $current_brightness = 0 ]; then
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echo 0.1
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return
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fi
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target=$((current_brightness * 100 / $change_percent))
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[ $target -ne $current_brightness ] || target=$((target - 1))
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;;
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esac
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# Boundaries
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if [ $target -le 1 ]; then echo 0.1; return; fi
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if [ $target -ge 100 ]; then echo 100; return; fi
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echo $target
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}
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target=$(new_target "$1")
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echo $target
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# Smoothly set the new brightness
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xbacklight -time 100 -fps 60 -set $target
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