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christiangenco/brightness

Created February 6, 2026 03:39
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  1. christiangenco created this gist Feb 6, 2026.
    90 changes: 90 additions & 0 deletions brightness
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,90 @@
    #!/bin/bash
    # Software brightness control via hyprsunset
    # Usage: brightness up|down|set <value>
    # Stores state in ~/.local/state/brightness
    #
    # Two phases:
    # 100% → 15%: reduce gamma (dims the screen while maintaining contrast)
    # 15% → 0%: gamma stays at 15%, temperature shifts warm (6500K → 2000K)
    # This "dims" further by removing blue light, keeping readability

    STATE_FILE="$HOME/.local/state/brightness"
    STEP=5
    MIN=0
    MAX=100

    # Below this gamma level, stop dimming and start warming instead
    GAMMA_FLOOR=20

    # Warm color temp range
    TEMP_NEUTRAL=6500
    TEMP_WARMEST=2000

    # Read current brightness
    if [[ -f "$STATE_FILE" ]]; then
    current=$(cat "$STATE_FILE")
    else
    current=100
    fi

    case "$1" in
    up)
    new=$((current + STEP))
    [[ $new -gt $MAX ]] && new=$MAX
    ;;
    down)
    new=$((current - STEP))
    [[ $new -lt $MIN ]] && new=$MIN
    ;;
    set)
    new=$2
    [[ $new -gt $MAX ]] && new=$MAX
    [[ $new -lt $MIN ]] && new=$MIN
    ;;
    get)
    echo "$current"
    exit 0
    ;;
    *)
    echo "Usage: brightness up|down|set <value>|get"
    exit 1
    ;;
    esac

    # Save new value
    echo "$new" > "$STATE_FILE"

    # Calculate gamma and temperature
    if [[ $new -ge $GAMMA_FLOOR ]]; then
    # Phase 1: normal dimming, neutral color
    gamma=$new
    temp=$TEMP_NEUTRAL
    else
    # Phase 2: gamma stays at floor, temperature goes warm
    gamma=$GAMMA_FLOOR
    # Linear interpolation: at 15% = 6500K, at 0% = 2000K
    temp_range=$((TEMP_NEUTRAL - TEMP_WARMEST))
    progress=$((GAMMA_FLOOR - new))
    temp=$((TEMP_NEUTRAL - (progress * temp_range / GAMMA_FLOOR)))
    fi

    # Apply via hyprsunset (kill existing instance first)
    pkill -x hyprsunset 2>/dev/null
    sleep 0.1

    if [[ $gamma -ge 100 && $temp -eq $TEMP_NEUTRAL ]]; then
    # Full brightness, no color shift — no need for hyprsunset
    :
    else
    hyprsunset -g "$gamma" -t "$temp" &>/dev/null &
    disown
    fi

    # Show OSD notification
    if [[ $new -ge $GAMMA_FLOOR ]]; then
    notify-send -t 1000 -h string:x-canonical-private-synchronous:brightness \
    -h int:value:"$new" "Brightness ${new}%"
    else
    notify-send -t 1000 -h string:x-canonical-private-synchronous:brightness \
    -h int:value:"$new" "Brightness ${new}% (${temp}K)"
    fi