less cpu usage and set 1 as the final value

if sensor is less than 3, sets to 1.
if xfce brightness bug puts actual_brightness to 0, it will goes to 1 with less than 3 in anbient or more with greater than 3 anbient..

add service in :"/etc/systemd/system/" to auto start and auto restart if broken in e.g. suspend. Works even in the greeter.

autobrightness.sh

@@ -0,0 +1,156 @@
+#!/bin/bash
+
+#decrease cpu usage
+cpu_limit=20 # CPU limit, adjust as needed
+
+# Set the priority of the current script
+renice "$cpu_limit" "$$"
+
+
+
+
+# How much light change must be seen by the sensor before it will act
+LightChange=10
+
+# How often it checks the sensor
+SensorDelay=1
+
+# Scale sensor to display brightness range
+SensorToDisplayScale=24
+
+# This should match your refresh rate otherwise it will either change the backlight more times than needed or too few for a smooth animation
+LevelSteps=60
+# The is should match the LevelSteps but in the actual time each event should take to see
+AnimationDelay=0.016
+
+# Read the variable names
+MaxScreenBrightness=937
+MinimumBrightness=1
+
+# 2 : Default | 1 : Add Offset | 0 : Subtract Offset, Recommended not to change
+op=2
+
+# Function to smoothly increase brightness
+smoothly_increase_brightness() {
+  current_brightness=$(cat /sys/class/backlight/intel_backlight/brightness)
+  target_brightness=1
+
+  steps=60  # You can adjust the number of steps for smoother transition
+  animation_delay=0.016
+
+  diff_count=$((($target_brightness - $current_brightness) / $steps))
+
+  for ((i = 1; i <= $steps; i++)); do
+    new_brightness=$((current_brightness + i * diff_count))
+    brightnessctl -q s $new_brightness
+    sleep $animation_delay
+  done
+
+  # Set the final brightness value
+  brightnessctl -q s $target_brightness
+}
+
+while getopts i:d: flag; do
+  case "${flag}" in
+    i) op=1
+       num=${OPTARG};;
+    d) op=0 
+       num=${OPTARG};;
+  esac
+done
+
+if [[ -f /tmp/AB.offset ]]; then
+  OffSet=$(cat /tmp/AB.offset)
+else
+  OffSet=0
+  echo $OffSet > /tmp/AB.offset
+fi
+
+OffSet=$((OffSet < 0 ? 0 : OffSet))
+
+if [[ $op -lt 2 ]]; then
+  if [[ $op -eq 1 ]]; then
+    OffSet=$((OffSet + num))
+  else 
+    OffSet=$((OffSet - num))
+  fi
+
+  OffSet=$((OffSet < 0 ? 0 : OffSet))
+  echo $OffSet > /tmp/AB.offset
+  exit
+fi
+
+touch '/tmp/AB.running'
+
+OldLight=$(cat /sys/bus/iio/devices/iio:device5/in_illuminance_raw)
+
+until [ -f /tmp/AB.kill ]; do
+  if [[ -f /tmp/AB.stop ]]; then
+    rm '/tmp/AB.stop'
+    rm '/tmp/AB.running'
+
+    until [[ -f /tmp/AB.start ]]; do
+      sleep 10
+    done
+
+    rm '/tmp/AB.start'
+    touch '/tmp/AB.running'
+  else
+    if [[ -f /tmp/AB.offset ]]; then
+      OffSet=$(cat /tmp/AB.offset)
+    else
+      OffSet=0
+      echo $OffSet > /tmp/AB.offset
+    fi
+
+    Light=$(cat /sys/bus/iio/devices/iio:device5/in_illuminance_raw)
+    Light=$((Light + OffSet))
+
+    if [[ $Light -lt $LightChange ]]; then
+      MaxOld=$((OldLight + LightChange))
+      MinOld=$((OldLight - LightChange))
+    else
+      MaxOld=$((OldLight + OldLight/LightChange))
+      MinOld=$((OldLight - OldLight/LightChange))
+    fi
+
+    if [[ $Light -gt $MaxOld ]] || [[ $Light -lt $MinOld ]]; then
+      CurrentBrightness=$(cat /sys/class/backlight/intel_backlight/brightness)
+      Light=$(( $Light + $MinimumBrightness ))
+      TempLight=$(($Light * $SensorToDisplayScale))
+
+      if [[ $TempLight -gt $MaxScreenBrightness ]]; then
+        NewLight=$MaxScreenBrightness
+      else
+        NewLight=$TempLight
+      fi
+
+      DiffCount=$(( ($NewLight - $CurrentBrightness)/$LevelSteps ))
+
+      for i in $(eval echo {1..$LevelSteps}); do
+        NewLight=$(( $DiffCount ))
+
+        if [[ $NewLight -lt 0 ]]; then
+          NewLight=$( echo "$NewLight" | awk -F "-" {'print$2'})
+          NewLight=$(echo $NewLight-)
+        else
+          NewLight=$(echo +$NewLight)
+        fi
+
+        brightnessctl -q s $NewLight
+        sleep $AnimationDelay
+      done
+
+      OldLight=$Light
+    fi
+
+    if [[ $Light -lt 3 ]]; then
+      smoothly_increase_brightness
+    fi
+
+    sleep $SensorDelay
+  fi
+done
+
+rm '/tmp/AB.running'
+rm '/tmp/AB.kill'