[gnome-documents] preview: Toggle the controls when the user taps on a touchscreen

[Debarshi Ray <debarshir src gnome org>]

commit 41efd7d31fc78d1c5135c32028dcd48105f40342
Author: Debarshi Ray <debarshir gnome org>
Date:   Wed Feb 25 18:39:40 2015 +0100

    preview: Toggle the controls when the user taps on a touchscreen
    
    Tapping on a touchscreen will toggle the visibility of the overlaid
    controls without using an auto-hide timeout. The timeout is only used
    when interacting with the mouse. Moving the mouse will continue to
    reveal the controls and auto-hide them based on a timeout, as before.
    
    To make the mouse and touchscreen interactions work together, the
    queueing and unqueing of the timeout has been split out and used
    explicitly where they are needed. An additional variable has been
    introduced to control the visibility of the controls based on internal
    conditions, as opposed to requests from external client code.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=741564

 src/preview.js |   37 +++++++++++++++++++++++++++----------
 1 files changed, 27 insertions(+), 10 deletions(-)
---
diff --git a/src/preview.js b/src/preview.js
index af096f3..db3d6d9 100644
--- a/src/preview.js
+++ b/src/preview.js
@@ -572,10 +572,10 @@ const PreviewNavControls = new Lang.Class({
         this._overlay = overlay;
 
         this._visible = false;
+        this._visibleInternal = false;
         this._pageChangedId = 0;
         this._autoHideId = 0;
         this._motionId = 0;
-        this._hover = false;
 
         this.bar_widget = new GdPrivate.NavBar({ document_model: this._model,
                                                  margin: _PREVIEW_NAVBAR_MARGIN,
@@ -634,23 +634,28 @@ const PreviewNavControls = new Lang.Class({
 
         this._overlay.connect('motion-notify-event', Lang.bind(this, this._onMotion));
 
+        this._tapGesture = new Gtk.GestureMultiPress({ propagation_phase: Gtk.PropagationPhase.CAPTURE,
+                                                       touch_only: true,
+                                                       widget: this._previewView.view });
+        this._tapGesture.connect('released', Lang.bind(this, this._onMultiPressReleased));
+        this._tapGesture.connect('stopped', Lang.bind(this, this._onMultiPressStopped));
     },
 
     _onEnterNotify: function() {
-        this._hover = true;
         this._unqueueAutoHide();
         return false;
     },
 
     _onLeaveNotify: function() {
-        this._hover = false;
         this._queueAutoHide();
         return false;
     },
 
     _motionTimeout: function() {
         this._motionId = 0;
+        this._visibleInternal = true;
         this._updateVisibility();
+        this._queueAutoHide();
         return false;
     },
 
@@ -668,6 +673,17 @@ const PreviewNavControls = new Lang.Class({
         return false;
     },
 
+    _onMultiPressReleased: function() {
+        this._tapGesture.set_state(Gtk.EventSequenceState.CLAIMED);
+        this._visibleInternal = !this._visibleInternal;
+        this._unqueueAutoHide();
+        this._updateVisibility();
+    },
+
+    _onMultiPressStopped: function() {
+        this._tapGesture.set_state(Gtk.EventSequenceState.DENIED);
+    },
+
     _onPrevClicked: function() {
         this._previewView.view.previous_page();
     },
@@ -677,10 +693,9 @@ const PreviewNavControls = new Lang.Class({
     },
 
     _autoHide: function() {
-        this._fadeOutButton(this.bar_widget);
-        this._fadeOutButton(this.prev_widget);
-        this._fadeOutButton(this.next_widget);
         this._autoHideId = 0;
+        this._visibleInternal = false;
+        this._updateVisibility();
         return false;
     },
 
@@ -698,7 +713,7 @@ const PreviewNavControls = new Lang.Class({
     },
 
     _updateVisibility: function() {
-        if (!this._model || !this._visible) {
+        if (!this._model || !this._visible || !this._visibleInternal) {
             this._fadeOutButton(this.bar_widget);
             this._fadeOutButton(this.prev_widget);
             this._fadeOutButton(this.next_widget);
@@ -717,9 +732,6 @@ const PreviewNavControls = new Lang.Class({
             this._fadeInButton(this.next_widget);
         else
             this._fadeOutButton(this.next_widget);
-
-        if (!this._hover)
-            this._queueAutoHide();
     },
 
     setModel: function(model) {
@@ -735,6 +747,7 @@ const PreviewNavControls = new Lang.Class({
             this._pageChangedId = this._model.connect('page-changed', Lang.bind(this, 
this._updateVisibility));
 
         this._updateVisibility();
+        this._queueAutoHide();
     },
 
     _fadeInButton: function(widget) {
@@ -758,11 +771,14 @@ const PreviewNavControls = new Lang.Class({
 
     show: function() {
         this._visible = true;
+        this._visibleInternal = true;
         this._updateVisibility();
+        this._queueAutoHide();
     },
 
     hide: function() {
         this._visible = false;
+        this._visibleInternal = false;
         this._updateVisibility();
     },
 
@@ -770,6 +786,7 @@ const PreviewNavControls = new Lang.Class({
         this.bar_widget.destroy();
         this.prev_widget.destroy();
         this.next_widget.destroy();
+        this._tapGesture = null;
     }
 });