[gnome-shell/wip/pressure: 206/207] layout: Trigger the message tray by downward pressure

[Jasper St. Pierre <jstpierre src gnome org>]

commit 54febe3d1099630d23ad63da7ce52472b1c01479
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Mon Jul 30 16:25:07 2012 -0300

    layout: Trigger the message tray by downward pressure
    
    https://bugzilla.gnome.org/show_bug.cgi?id=677215

 js/ui/layout.js      |   93 ++++++++++++++++++++++++++++++++++++++++++++------
 js/ui/messageTray.js |   37 +-------------------
 2 files changed, 83 insertions(+), 47 deletions(-)
---
diff --git a/js/ui/layout.js b/js/ui/layout.js
index 493c73a..cc7c792 100644
--- a/js/ui/layout.js
+++ b/js/ui/layout.js
@@ -18,6 +18,8 @@ const HOT_CORNER_ACTIVATION_TIMEOUT = 0.5;
 const STARTUP_ANIMATION_TIME = 0.2;
 const KEYBOARD_ANIMATION_TIME = 0.5;
 
+const MESSAGE_TRAY_PRESSURE_THRESHOLD = 3000;
+
 const MonitorConstraint = new Lang.Class({
     Name: 'MonitorConstraint',
     Extends: Clutter.Constraint,
@@ -102,7 +104,8 @@ const LayoutManager = new Lang.Class({
         this._hotCorners = [];
         this._leftPanelBarrier = null;
         this._rightPanelBarrier = null;
-        this._trayBarrier = null;
+        this._vertTrayBarrier = null;
+        this._horizTrayBarrier = null;
 
         this._chrome = new Chrome(this);
 
@@ -123,7 +126,7 @@ const LayoutManager = new Lang.Class({
         this.trayBox = new St.BoxLayout({ name: 'trayBox' }); 
         this.addChrome(this.trayBox);
         this.trayBox.connect('allocation-changed',
-                             Lang.bind(this, this._updateTrayBarrier));
+                             Lang.bind(this, this._updateTrayBarriers));
 
         this.keyboardBox = new St.BoxLayout({ name: 'keyboardBox',
                                               reactive: true,
@@ -277,19 +280,34 @@ const LayoutManager = new Lang.Class({
         }
     },
 
-    _updateTrayBarrier: function() {
+    _updateTrayBarriers: function() {
         let monitor = this.bottomMonitor;
 
-        if (this._trayBarrier) {
-            this._trayBarrier.destroy();
-            this._trayBarrier = null;
+        if (this._vertTrayBarrier) {
+            this._vertTrayBarrier.destroy();
+            this._vertTrayBarrier = null;
+        }
+
+        if (this._horizTrayBarrier) {
+            this._horizTrayBarrier.destroy();
+            this._horizTrayBarrier = null;
         }
 
         if (Main.messageTray) {
-            this._trayBarrier = new Meta.Barrier({ display: global.display,
-                                                   x1: monitor.x + monitor.width, y1: monitor.y + monitor.height - Main.messageTray.actor.height,
-                                                   x2: monitor.x + monitor.width, y2: monitor.y + monitor.height,
-                                                   directions: Meta.BarrierDirection.NEGATIVE_X });
+            this._vertTrayBarrier = new Meta.Barrier({ display: global.display,
+                                                       x1: monitor.x + monitor.width, y1: monitor.y + monitor.height - Main.messageTray.actor.height,
+                                                       x2: monitor.x + monitor.width, y2: monitor.y + monitor.height,
+                                                       directions: Meta.BarrierDirection.NEGATIVE_X });
+
+            this._horizTrayBarrier = new Meta.Barrier({ display: global.display,
+                                                        x1: monitor.x, x2: monitor.x + monitor.width,
+                                                        y1: monitor.y + monitor.height, y2: monitor.y + monitor.height,
+                                                        directions: Meta.BarrierDirection.NEGATIVE_Y });
+
+            this._horizTrayPressure = new PressureBarrier(this._horizTrayBarrier, MESSAGE_TRAY_PRESSURE_THRESHOLD);
+            this._horizTrayPressure.connect('trigger', function() {
+                Main.messageTray.openTray();
+            });
         }
     },
 
@@ -1052,5 +1070,58 @@ const Chrome = new Lang.Class({
         return false;
     }
 });
-
 Signals.addSignalMethods(Chrome.prototype);
+
+const PressureBarrier = new Lang.Class({
+    Name: 'TrayPressure',
+
+    _init: function(barrier, threshold) {
+        this._barrier = barrier;
+        this._threshold = threshold;
+        this._getVelocity = this._makeGetVelocity(barrier);
+
+        this._reset(0);
+
+        this._barrierHitId = this._barrier.connect('hit', Lang.bind(this, this._onBarrierHit));
+    },
+
+    destroy: function() {
+        this._barrier.disconnect(this._barrierHitId);
+        this._barrier = null;
+    },
+
+    _reset: function(eventId) {
+        this._currentEventId = eventId;
+        this._currentPressure = 0;
+    },
+
+    _makeGetVelocity: function(barrier) {
+        if (barrier.y1 === barrier.y2) {
+            return function(event) {
+                return Math.abs(event.dy);
+            };
+        } else {
+            return function(event) {
+                return Math.abs(event.dx);
+            };
+        }
+    },
+
+    _onBarrierHit: function(barrier, event) {
+        // Event IDs are incremented every time the user stops
+        // hitting the barrier. So, if the event ID switches,
+        // reset the current state, and start over.
+        if (this._currentEventId != event.event_id) {
+            this._reset(event.event_id);
+        }
+
+        let velocity = this._getVelocity(event);
+
+        this._currentPressure += velocity;
+        if (this._currentPressure >= this._threshold) {
+            this.emit('trigger');
+            this._reset(0);
+        }
+    }
+});
+Signals.addSignalMethods(PressureBarrier.prototype);
diff --git a/js/ui/messageTray.js b/js/ui/messageTray.js
index 2d7ef8e..2dcd649 100644
--- a/js/ui/messageTray.js
+++ b/js/ui/messageTray.js
@@ -1489,44 +1489,9 @@ const MessageTray = new Lang.Class({
 
         this._summaryItems = [];
         this._chatSummaryItemsCount = 0;
-
-        let pointerWatcher = PointerWatcher.getPointerWatcher();
-        pointerWatcher.addWatch(TRAY_DWELL_CHECK_INTERVAL, Lang.bind(this, this._checkTrayDwell));
-        this._trayDwellTimeoutId = 0;
-        this._trayDwelling = false;
     },
 
-    _checkTrayDwell: function(x, y) {
-        let monitor = Main.layoutManager.bottomMonitor;
-        let shouldDwell = (x >= monitor.x && x <= monitor.x + monitor.width &&
-                           y == monitor.y + monitor.height - 1);
-        if (shouldDwell) {
-            // We only set up dwell timeout when the user is not hovering over the tray
-            // (!this.actor.hover). This avoids bringing up the message tray after the
-            // user clicks on a notification with the pointer on the bottom pixel
-            // of the monitor. The _trayDwelling variable is used so that we only try to
-            // fire off one tray dwell - if it fails (because, say, the user has the mouse down),
-            // we don't try again until the user moves the mouse up and down again.
-            if (!this._trayDwelling && !this.actor.hover && this._trayDwellTimeoutId == 0)
-                this._trayDwellTimeoutId = Mainloop.timeout_add(TRAY_DWELL_TIME,
-                                                                Lang.bind(this, this._trayDwellTimeout));
-            this._trayDwelling = true;
-        } else {
-            this._cancelTrayDwell();
-            this._trayDwelling = false;
-        }
-    },
-
-    _cancelTrayDwell: function() {
-        if (this._trayDwellTimeoutId != 0) {
-            Mainloop.source_remove(this._trayDwellTimeoutId);
-            this._trayDwellTimeoutId = 0;
-        }
-    },
-
-    _trayDwellTimeout: function() {
-        this._trayDwellTimeoutId = 0;
-
+    openTray: function() {
         this._traySummoned = true;
         this._updateState();