alien: enable and use i2c and ddcutil

home/tiling/niri/scripts/brightness.sh

@@ -1,5 +1,4 @@
 #!/usr/bin/env bash
-
 WAYBAR_SIGNAL=8   # SIGRTMIN+8
 
 if [ "$#" -ne 1 ]; then
@@ -15,15 +14,33 @@ if ! [[ "$value" =~ ^-?[0-9]+$ ]] || [ "$value" -lt -100 ] || [ "$value" -gt 100
     exit 1
 fi
 
-# Apply brightness change with correct syntax
-if [ "$value" -gt 0 ]; then
-    brightnessctl s "+${value}%" >/dev/null
-elif [ "$value" -lt 0 ]; then
-    brightnessctl s "${value#-}%-" >/dev/null
+# Determine which brightness control tool to use
+if command -v ddcutil >/dev/null 2>&1; then
+    # Get current brightness
+    current=$(ddcutil getvcp 10 | grep -oP 'current value =\s+\K\d+')
+
+    if [ -z "$current" ]; then
+        echo "Error: failed to read current brightness from ddcutil" >&2
+        exit 1
+    fi
+
+    # Calculate new brightness (ddcutil uses absolute 0-100 scale)
+    new=$((current + value))
+
+    # Clamp to valid range
+    [ "$new" -lt 0 ] && new=0
+    [ "$new" -gt 100 ] && new=100
+
+    # Set new brightness
+    ddcutil setvcp 10 "$new" >/dev/null 2>&1
 else
-    : # no-op for 0
+    # Fallback to brightnessctl
+    if [ "$value" -gt 0 ]; then
+        brightnessctl s "+${value}%" >/dev/null
+    elif [ "$value" -lt 0 ]; then
+        brightnessctl s "${value#-}%-" >/dev/null
+    fi
 fi
 
 # Notify Waybar to refresh
 pkill -RTMIN+"$WAYBAR_SIGNAL" waybar
-