fix: use xsetwacom MapToOutput instead of xinput set-prop for CTM

The Wacom driver owns the Coordinate Transformation Matrix and silently
overrides any xinput set-prop changes. xsetwacom MapToOutput tells the
driver to recalculate the CTM for the primary connected output, which is
the correct API and persists across driver resets.

Dynamically detects the primary output (eDP1, HDMI1, DP1, etc.) so the
fix works on any machine without hardcoding a display name.

https://claude.ai/code/session_01EyjEQLWbTXcZgbMDarf7NU

ubuntu-based-kiosk-v1.0.3.sh

@@ -7347,12 +7347,17 @@ for i in {1..10}; do
 done
 
 # Fix touch device coordinate mapping and enable multi-touch gestures.
+# Find the primary connected display (e.g. eDP1, HDMI1, DP1).
+_primary_output=$(xrandr 2>/dev/null | grep " connected primary" | head -1 | cut -d' ' -f1)
+
 # Loop over all touch/finger input devices (excludes touchpads).
 while IFS= read -r dev; do
-  # Reset Coordinate Transformation Matrix to identity — without this,
-  # the Wacom driver can initialise the CTM to all-zeros, which maps
-  # every touch to (0,0) on screen and makes the touchscreen appear dead.
-  xinput set-prop "$dev" "Coordinate Transformation Matrix" 1 0 0 0 1 0 0 0 1 2>/dev/null || true
+  # Use xsetwacom MapToOutput to fix the Coordinate Transformation Matrix.
+  # The Wacom driver initialises the CTM to all-zeros when it cannot auto-detect
+  # the active output, making every touch map to (0,0) and appear dead.
+  # xsetwacom MapToOutput recalculates the CTM correctly for the given output.
+  # xinput set-prop on the CTM is overridden by the driver, so xsetwacom is needed.
+  [ -n "$_primary_output" ] && xsetwacom set "$dev" MapToOutput "$_primary_output" 2>/dev/null || true
   # Enable multi-touch gesture mode (Wacom-specific; ignored by other drivers).
   xinput set-prop "$dev" "Wacom Enable Touch Gesture" 1 2>/dev/null || true
 done < <(xinput list --name-only 2>/dev/null | grep -i "touch\|finger" | grep -iv "touchpad\|trackpad")