viewSelector: Add left edge drag gesture to show the app picker

js/ui/viewSelector.js

@@ -49,6 +49,77 @@ function getTermsForSearchString(searchString) {
     return terms;
 }
 
+const EDGE_THRESHOLD = 20;
+const DRAG_DISTANCE = 80;
+
+const EdgeDragAction = new Lang.Class({
+    Name: 'EdgeDragAction',
+    Extends: Clutter.GestureAction,
+
+    _init : function(side) {
+        this.parent();
+        this._side = side;
+        this.set_n_touch_points(1);
+
+        global.display.connect('grab-op-begin', Lang.bind(this, function() {
+            this.cancel();
+        }));
+    },
+
+    _getMonitorRect : function (x, y) {
+        let rect = new Meta.Rectangle({ x: x - 1, y: y - 1, width: 1, height: 1 });
+        let monitorIndex = global.screen.get_monitor_index_for_rect(rect);
+
+        return global.screen.get_monitor_geometry(monitorIndex);
+    },
+
+    vfunc_gesture_prepare : function(action, actor) {
+        if (this.get_n_current_points() == 0)
+            return false;
+
+        let [x, y] = this.get_press_coords(0);
+        let monitorRect = this._getMonitorRect(x, y);
+
+        return ((this._side == St.Side.LEFT && x < monitorRect.x + EDGE_THRESHOLD) ||
+                (this._side == St.Side.RIGHT && x > monitorRect.x + monitorRect.width - EDGE_THRESHOLD) ||
+                (this._side == St.Side.TOP && y < monitorRect.y + EDGE_THRESHOLD) ||
+                (this._side == St.Side.BOTTOM && y > monitorRect.y + monitorRect.height - EDGE_THRESHOLD));
+    },
+
+    vfunc_gesture_progress : function (action, actor) {
+        let [startX, startY] = this.get_press_coords(0);
+        let [x, y] = this.get_motion_coords(0);
+        let offsetX = Math.abs (x - startX);
+        let offsetY = Math.abs (y - startY);
+
+        if (offsetX < EDGE_THRESHOLD && offsetY < EDGE_THRESHOLD)
+            return true;
+
+        if ((offsetX > offsetY &&
+             (this._side == St.Side.TOP || this._side == St.Side.BOTTOM)) ||
+            (offsetY > offsetX &&
+             (this._side == St.Side.LEFT || this._side == St.Side.RIGHT))) {
+            this.cancel();
+            return false;
+        }
+
+        return true;
+    },
+
+    vfunc_gesture_end : function (action, actor) {
+        let [startX, startY] = this.get_press_coords(0);
+        let [x, y] = this.get_motion_coords(0);
+        let monitorRect = this._getMonitorRect(startX, startY);
+
+        if ((this._side == St.Side.TOP && y > monitorRect.y + DRAG_DISTANCE) ||
+            (this._side == St.Side.BOTTOM && y < monitorRect.y + monitorRect.height - DRAG_DISTANCE) ||
+            (this._side == St.Side.LEFT && x > monitorRect.x + DRAG_DISTANCE) ||
+            (this._side == St.Side.RIGHT && x < monitorRect.x + monitorRect.width - DRAG_DISTANCE))
+            this.emit('activated');
+    }
+});
+Signals.addSignalMethods(EdgeDragAction.prototype);
+
 const ViewSelector = new Lang.Class({
     Name: 'ViewSelector',
 
@@ -145,6 +216,14 @@ const ViewSelector = new Lang.Class({
                               Shell.KeyBindingMode.OVERVIEW,
                               Lang.bind(Main.overview, Main.overview.toggle));
 
+        let gesture = new EdgeDragAction(St.Side.RIGHT);
+        gesture.connect('activated', Lang.bind(this, function() {
+            if (Main.overview.visible)
+                Main.overview.hide();
+            else
+                this.showApps();
+        }));
+        global.stage.add_action(gesture);
     },
 
     _toggleAppsPage: function() {