Add head follow: the pointer comes along when you turn your head

Off by default. With POINTER_FOLLOW=1 (a switch on the Pointer page of
Frametop Input Settings, or a mouse button mapped to Head follow on/off),
the cursor rides on a reference direction leashed POINTER_LEASH_DEG (10)
from where you face. Within the leash it stays put in the room; past it,
it turns with your head and keeps its offset. A leash of 0 locks it to
your view. Head roll is ignored, the cursor stays within 40 degrees of
the reference, and it holds still in the room while the left button is
down so the head can't nudge a click or a drag.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

input-settings/ft_input_settings.py

@@ -37,7 +37,8 @@ DEFAULT_BUTTONS = {0x110: "left", 0x111: "right", 0x112: "middle", 0x113: "back"
 ACTION_LABELS = {
     "left": "Left click", "right": "Right click", "middle": "Middle click", "back": "Back",
     "scroll_up": "Scroll up", "scroll_down": "Scroll down", "dashboard": "Toggle SteamVR dashboard",
-    "recenter": "Recenter pointer", "pointer_toggle": "Pointer on/off", "sens_up": "Faster pointer",
+    "recenter": "Recenter pointer", "pointer_toggle": "Pointer on/off",
+    "follow_toggle": "Head follow on/off", "sens_up": "Faster pointer",
     "sens_down": "Slower pointer", "layout_reset": "Reset desktop screen layout",
     "screens_toggle": "Hide/show desktop screens", "key": "Pass through as key",
     "none": "Do nothing",
@@ -52,6 +53,7 @@ POINTER_SETTINGS = [
     ("POINTER_ORIGIN_MARGIN", "Room for small controls", 0.15, 0.03, 0.5, 0.01, "m"),
     ("POINTER_SCENE_RADIUS", "Dock / window-control reach", 0.5, 0.1, 1.5, 0.05, "m"),
     ("POINTER_EDGE_REACH", "Panel edge reach", 0.3, 0.0, 1.0, 0.05, "m"),
+    ("POINTER_LEASH_DEG", "Head follow leash", 10, 0, 60, 1, "°"),
     ("POINTER_WAKE_COUNTS", "Movement to wake", 40, 5, 200, 5, "counts"),
     ("POINTER_IDLE", "Release after idle", 30, 5, 120, 5, "s"),
 ]
@@ -356,11 +358,21 @@ class Backend(QObject):
 
     @Slot(str, float)
     def setPointerSetting(self, key, value):
-        integer = key in ("POINTER_WAKE_COUNTS", "POINTER_IDLE")
+        integer = key in ("POINTER_WAKE_COUNTS", "POINTER_IDLE", "POINTER_LEASH_DEG")
         write_conf_value(key, str(int(round(value))) if integer else f"{value:.3f}".rstrip("0").rstrip("."))
         self.reload_timer.start()  # debounce slider drags
         self.pointerChanged.emit()
 
+    @Property(bool, notify=pointerChanged)
+    def pointerFollow(self):
+        return read_conf().get("POINTER_FOLLOW", "0") not in ("", "0")
+
+    @Slot(bool)
+    def setPointerFollow(self, on):
+        write_conf_value("POINTER_FOLLOW", "1" if on else "0")
+        self.reload_timer.start()
+        self.pointerChanged.emit()
+
     @Slot(result=bool)
     def recenter(self):
         return self._send("recenter", HELPER)

input-settings/main.qml

@@ -314,6 +314,12 @@ Kirigami.ApplicationWindow {
             ]
 
             Kirigami.FormLayout {
+                Controls.Switch {
+                    Kirigami.FormData.label: "Head follow:"
+                    text: "Pointer follows your head (leash below; 0° locks it to your view)"
+                    checked: backend.pointerFollow
+                    onToggled: backend.setPointerFollow(checked)
+                }
                 Repeater {
                     model: backend.pointerSettings
                     delegate: RowLayout {