[gnome-shell/wip/paging-release2: 20/22] appDisplay: Add pan action to FolderView

[Carlos Soriano <csoriano src gnome org>]

commit 0ad4e93450e2bf3fa6cdf0c2829752aeb9bbade7
Author: Carlos Soriano <carlos soriano89 gmail com>
Date:   Fri Aug 23 20:49:27 2013 +0200

    appDisplay: Add pan action to FolderView
    
    Since we have now a ScrollView in the FolderView,
    add support for the pan action
    
    https://bugzilla.gnome.org/show_bug.cgi?id=706081

 js/ui/appDisplay.js |   12 ++++++++++++
 1 files changed, 12 insertions(+), 0 deletions(-)
---
diff --git a/js/ui/appDisplay.js b/js/ui/appDisplay.js
index 0e5646a..823d1e1 100644
--- a/js/ui/appDisplay.js
+++ b/js/ui/appDisplay.js
@@ -1012,6 +1012,11 @@ const FolderView = new Lang.Class({
 
         this.actor = new St.ScrollView({ overlay_scrollbars: true });
         this.actor.set_policy(Gtk.PolicyType.NEVER, Gtk.PolicyType.AUTOMATIC);
+
+        let action = new Clutter.PanAction({ interpolate: true });
+        action.connect('pan', Lang.bind(this, this._onPan));
+        this.actor.add_action(action);
+
         this._box = new St.BoxLayout({ vertical: true, reactive: true });
         this._widget = new St.Widget({ layout_manager: new Clutter.BinLayout() });
         this._widget.add_child(this._grid.actor);
@@ -1056,6 +1061,13 @@ const FolderView = new Lang.Class({
         return icon;
     },
 
+    _onPan: function(action) {
+        let [dist, dx, dy] = action.get_motion_delta(0);
+        let adjustment = this.actor.vscroll.adjustment;
+        adjustment.value -= (dy / this.actor.height) * adjustment.page_size;
+        return false;
+    },
+
     adaptToSize: function(width, height) {
         this._parentAvailableWidth = width;
         this._parentAvailableHeight = height;