[gnome-maps/wip/mlundblad/touch-gestures] mapView: WIP: implement swipe gesture to bring up the sidebar

[Marcus Lundblad <mlundblad src gnome org>]

commit c80eb10f71f032431119555018e54d888fcc8246
Author: Marcus Lundblad <ml update uu se>
Date:   Thu Oct 19 23:54:16 2017 +0200

    mapView: WIP: implement swipe gesture to bring up the sidebar

 src/mapView.js |   34 ++++++++++++++++++++++++++++++++++
 1 files changed, 34 insertions(+), 0 deletions(-)
---
diff --git a/src/mapView.js b/src/mapView.js
index 363ae90..2dca680 100644
--- a/src/mapView.js
+++ b/src/mapView.js
@@ -24,6 +24,7 @@ const Clutter = imports.gi.Clutter;
 const GObject = imports.gi.GObject;
 const Geocode = imports.gi.GeocodeGlib;
 const Gio = imports.gi.Gio;
+const Gtk = imports.gi.Gtk;
 const GtkChamplain = imports.gi.GtkChamplain;
 const Lang = imports.lang;
 const Mainloop = imports.mainloop;
@@ -86,6 +87,9 @@ const DASHED_ROUTE_LINE_FILLED_LENGTH = 5;
 // length of gaps of dashed lines used for walking legs of transit itineraries
 const DASHED_ROUTE_LINE_GAP_LENGTH = 5;
 
+// threashhold to detect as a swipe-from-the edge gesture
+const SWIPE_EDGE_THREASHHOLD = 10;
+
 var MapView = new Lang.Class({
     Name: 'MapView',
     Extends: GtkChamplain.Embed,
@@ -160,6 +164,7 @@ var MapView = new Lang.Class({
                                     this._updateUserLocation.bind(this));
         this._storeId = 0;
         this._connectRouteSignals();
+        this._initGestures();
     },
 
     _initScale: function(view) {
@@ -201,6 +206,35 @@ var MapView = new Lang.Class({
         return view;
     },
 
+    _initGestures: function() {
+        this._swipeGesture =
+            new Gtk.GestureSwipe({ widget: this, 'touch-only': true });
+        this._panGesture = new Gtk.GesturePan({ widget: this,
+                                                'touch-only': true,
+                                                orientation: Gtk.Orientation.HORIZONTAL });
+        // restrict to horizontal swiping by grouping with a horizontal pan
+        this._swipeGesture.group(this._panGesture);
+        this._swipeGesture.connect('swipe', this._onSwipe.bind(this));
+        this._swipeGesture.connect('begin', this._onSwipeBegin.bind(this));
+    },
+
+    _onSwipeBegin: function(gesture, sequence) {
+        let rtl = Gtk.get_locale_direction() === Gtk.TextDirection.RTL;
+        Utils.debug('swipe begin');
+        let [_, x, y] = gesture.get_point(sequence);
+        Utils.debug('point: ' + x + ',' + y);
+        this._recognizeEdgeSwipe = rtl ?
+                                   x < SWIPE_EDGE_THREASHHOLD :
+                                   x > this.get_allocated_width() - SWIPE_EDGE_THREASHHOLD;
+        Utils.debug('recognized: ' + this._recognizeEdgeSwipe);
+    },
+
+    _onSwipe: function(gesture, velocityX, velocityY) {
+        Utils.debug('swipe: ' + velocityX + ', ' + velocityY);
+        if (this._recognizeEdgeSwipe)
+            Application.routeQuery.notify('points');
+    },
+
     /* create and store a route layer, pass true to get a dashed line */
     _createRouteLayer: function(dashed, lineColor, width) {
         let red = Color.parseColor(lineColor, 0);