cli for brightness and gamma adjustment for non apple monitors

[lvnilesh]

I am not super familiar with Omakub specific key-binding implementation so I am here to offer a simple cli script that helps in brightness and gamma control for non-apple monitors.

#! /bin/bash
# Script for adjusting display brightness and gamma
# This script assumes that you have two monitors connected via DP-0 and DP-4
# run `xrandr --verbose` or just `xrandr` to find the detail about the monitors you have connected.

# Ensure input is a valid number and convert it to a decimal
if [[ "$1" =~ ^[0-9]+$ ]] && (( $1 >= 1 && $1 <= 10 )); then
  [ "$1" = 10 ] && percent="1" || percent="0.$1"
else
  echo "Usage: $0 <brightness level (1-10)> [night]"
  exit 1
fi

# Ensure brightness is never lower than 0.1
(( $(echo "$percent < 0.1" | bc -l) )) && percent="0.1"

# Adjust brightness
xrandr --output DP-4 --brightness "$percent"
xrandr --output DP-0 --brightness "$percent"

# Adjust gamma if "night" mode is passed
if [ "$2" = "night" ]; then
  xrandr --output DP-4 --brightness "$percent" --gamma 1.0:0.95:0.85
  xrandr --output DP-0 --brightness "$percent" --gamma 1.0:0.95:0.85
else
  xrandr --output DP-4 --brightness "$percent" --gamma 1.0:1.0:1.0
  xrandr --output DP-0 --brightness "$percent" --gamma 1.0:1.0:1.0
fi

# Display current settings
xrandr --verbose | grep -E "Brightness|Gamma" | tail -n2

# Optional fun message
[ "$1" != 10 ] && echo "Stayin' up late, huh? Or maybe just pretending to be a hacker?" | lolcat

[lvnilesh]

here is the stepper script for brightness-control based on the above dimmer

For the non-apple monitor users, this stepper script could be mapped like this:

• CTRL-F1 brightness-control down

• CTRL-F2 brightness-control up

#!/bin/bash

# Get current brightness level
current_brightness=$(xrandr --verbose | grep -m 1 -i brightness | awk '{print $2}')

# Define step size for brightness change
step=0.1

# Adjust brightness based on argument
if [ "$1" = "up" ]; then
  new_brightness=$(echo "$current_brightness + $step" | bc)
elif [ "$1" = "down" ]; then
  new_brightness=$(echo "$current_brightness - $step" | bc)
else
  echo "Usage: $0 up|down"
  exit 1
fi

# Ensure brightness stays within 0.1 to 1.0 range
if (( $(echo "$new_brightness < 0.1" | bc -l) )); then
  new_brightness=0.1
elif (( $(echo "$new_brightness > 1.0" | bc -l) )); then
  new_brightness=1.0
fi

# Apply new brightness value
xrandr --output DP-4 --brightness "$new_brightness"
xrandr --output DP-0 --brightness "$new_brightness"

# Optional: Display new brightness
echo "Brightness set to: $new_brightness"

[lvnilesh]

# Turn bightness down on non-Apple monitor (requires brightness-control installed)
gsettings set org.gnome.settings-daemon.plugins.media-keys.custom-keybinding:/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom4/ name 'Apple Brightness Down (ASDControl)'
gsettings set org.gnome.settings-daemon.plugins.media-keys.custom-keybinding:/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom4/ binding '<Control>F1'
gsettings set org.gnome.settings-daemon.plugins.media-keys.custom-keybinding:/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom4/ command "sh -c 'brightness-control down"

# Turn bightness up on non-Apple monitor (requires brightness-control installed)
gsettings set org.gnome.settings-daemon.plugins.media-keys.custom-keybinding:/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom5/ name 'Apple Brightness Up (ASDControl)'
gsettings set org.gnome.settings-daemon.plugins.media-keys.custom-keybinding:/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom5/ binding '<Control>F2'
gsettings set org.gnome.settings-daemon.plugins.media-keys.custom-keybinding:/org/gnome/settings-daemon/plugins/media-keys/custom-keybindings/custom5/ command "sh -c 'brightness-control up'"

[dhh]

Nice! Looks like your script has hardcoded the monitors, though, right? With DP-4 and DP-0 mentioned explicitly. Would probably need something generic there.

[okdas]

Oh thanks @lvnilesh — this is something I need!

Will check what can be done with hardcoded monitors. couldn't run ubuntu on nvidia card.

[lvnilesh]

removed the hard-coding for display output identifiers.

#!/bin/bash

# --- Configuration ---
# Define step size for brightness change (e.g., 0.1 for 10%)
step=0.1
# Define minimum brightness (xrandr brightness can't be exactly 0)
min_brightness=0.1
# Define maximum brightness
max_brightness=1.0
# --- End Configuration ---

# Function to get the brightness of the first connected display reporting it
get_current_brightness() {
  xrandr --verbose | grep -A 5 ' connected' | grep -m 1 -i brightness | awk '{print $2}'
}

# Get current brightness level
current_brightness=$(get_current_brightness)

# Handle case where brightness might not be found (e.g., initial state or error)
# Or if the monitor doesn't report brightness via xrandr --verbose this way.
# We assume 1.0 as a default if we can't read it.
if [ -z "$current_brightness" ]; then
    echo "Warning: Could not determine current brightness from xrandr --verbose. Assuming ${max_brightness}."
    current_brightness=${max_brightness}
fi

# Adjust brightness based on argument
if [ "$1" = "up" ]; then
  # Use awk for floating point arithmetic
  new_brightness=$(awk -v current="$current_brightness" -v step="$step" 'BEGIN { print current + step }')
elif [ "$1" = "down" ]; then
  # Use awk for floating point arithmetic
  new_brightness=$(awk -v current="$current_brightness" -v step="$step" 'BEGIN { print current - step }')
else
  # Use basename for cleaner usage message independent of script path
  echo "Usage: $(basename "$0") up|down"
  exit 1
fi

# Ensure brightness stays within the defined range using awk for comparison
if awk -v nb="$new_brightness" -v minb="$min_brightness" 'BEGIN { exit !(nb < minb) }'; then
  new_brightness="$min_brightness"
elif awk -v nb="$new_brightness" -v maxb="$max_brightness" 'BEGIN { exit !(nb > maxb) }'; then
  new_brightness="$max_brightness"
fi

# Find all connected outputs using xrandr --query
# Grep for lines containing ' connected ' (with spaces to be more specific)
# Awk prints the first field ($1), which is the output name (e.g., DP-0, eDP-1)
connected_outputs=$(xrandr --query | grep ' connected ' | awk '{print $1}')

# Check if any connected outputs were found
if [ -z "$connected_outputs" ]; then
    echo "Error: No connected outputs found by xrandr."
    exit 1
fi

echo "Setting brightness to: $new_brightness"
echo "Applying to connected outputs:"

# Loop through each connected output and apply the new brightness
echo "$connected_outputs" | while IFS= read -r output_name; do
    echo " - $output_name"
    xrandr --output "$output_name" --brightness "$new_brightness"
done

echo "Brightness adjustment complete."