swipeTracker: Optionally require modifiers for scrolling

The design now calls for super-scroll for workspace switching
in the session, however it is currently only possible for
SwipeTracker to either handle scroll events or not.

In order to support the new use case, add a new :scroll-modifiers
property that allows specifying modifiers for which scroll events
are handled.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1612>

diff --git a/js/ui/swipeTracker.js b/js/ui/swipeTracker.js
index bed351f8329aec0187e752af33f08a6a8a83aa1c..2ce054ab19ac777a9073fa8930e0b7e7321dbc75 100644 (file)
--- a/js/ui/swipeTracker.js
+++ b/js/ui/swipeTracker.js
@@ -211,6 +211,10 @@ const ScrollGesture = GObject.registerClass({
             'orientation', 'orientation', 'orientation',
             GObject.ParamFlags.READWRITE,
             Clutter.Orientation, Clutter.Orientation.VERTICAL),
+        'scroll-modifiers': GObject.ParamSpec.flags(
+            'scroll-modifiers', 'scroll-modifiers', 'scroll-modifiers',
+            GObject.ParamFlags.READWRITE,
+            Clutter.ModifierType, 0),
     },
     Signals: {
         'begin':  { param_types: [GObject.TYPE_UINT, GObject.TYPE_DOUBLE, GObject.TYPE_DOUBLE] },
@@ -255,6 +259,10 @@ const ScrollGesture = GObject.registerClass({
         if ((this._allowedModes & Main.actionMode) === 0)
             return false;
 
+        if (this.scrollModifiers !== 0 &&
+            (event.get_state() & this.scrollModifiers) === 0)
+            return false;
+
         return true;
     }
 
@@ -336,6 +344,10 @@ var SwipeTracker = GObject.registerClass({
             'distance', 'distance', 'distance',
             GObject.ParamFlags.READWRITE,
             0, Infinity, 0),
+        'scroll-modifiers': GObject.ParamSpec.flags(
+            'scroll-modifiers', 'scroll-modifiers', 'scroll-modifiers',
+            GObject.ParamFlags.READWRITE,
+            Clutter.ModifierType, 0),
     },
     Signals: {
         'begin':  { param_types: [GObject.TYPE_UINT] },
@@ -394,6 +406,8 @@ var SwipeTracker = GObject.registerClass({
             this._scrollGesture.connect('end', this._endGesture.bind(this));
             this.bind_property('enabled', this._scrollGesture, 'enabled', 0);
             this.bind_property('orientation', this._scrollGesture, 'orientation', 0);
+            this.bind_property('scroll-modifiers',
+                this._scrollGesture, 'scroll-modifiers', 0);
         } else {
             this._scrollGesture = null;
         }