[gtk+] paned: Use GtkGestureDrag for anything else than touch

[Carlos Garnacho <carlosg src gnome org>]

commit e62f1604f97a6ca26aab4780fb9504c4b06a921e
Author: Carlos Garnacho <carlosg gnome org>
Date:   Thu Dec 24 19:03:02 2015 +0100

    paned: Use GtkGestureDrag for anything else than touch
    
    The GtkGesturePan behavior of locking onto certain orientations may
    come across as confusing, and is not strictly necessary for mice and
    other pointing devices.
    
    As GtkGesturePan is also a GtkGestureDrag, we just use the same
    callbacks on both gestures.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=759670

 gtk/gtkpaned.c |   67 ++++++++++++++++++++++++++++++++++++-------------------
 1 files changed, 44 insertions(+), 23 deletions(-)
---
diff --git a/gtk/gtkpaned.c b/gtk/gtkpaned.c
index 8c6495d..d7d791e 100644
--- a/gtk/gtkpaned.c
+++ b/gtk/gtkpaned.c
@@ -136,7 +136,8 @@ struct _GtkPanedPrivate
   GtkCssGadget  *gadget;
   GtkCssGadget  *handle_gadget;
 
-  GtkGesture    *pan_gesture;
+  GtkGesture    *pan_gesture;  /* Used for touch */
+  GtkGesture    *drag_gesture; /* Used for mice */
 
   gint          child1_size;
   gint          drag_pos;
@@ -738,10 +739,10 @@ initiates_touch_drag (GtkPaned *paned,
 }
 
 static void
-pan_gesture_drag_begin_cb (GtkGestureDrag *gesture,
-                           gdouble         start_x,
-                           gdouble         start_y,
-                           GtkPaned       *paned)
+gesture_drag_begin_cb (GtkGestureDrag *gesture,
+                       gdouble         start_x,
+                       gdouble         start_y,
+                       GtkPaned       *paned)
 {
   GtkPanedPrivate *priv = paned->priv;
   GdkEventSequence *sequence;
@@ -759,6 +760,14 @@ pan_gesture_drag_begin_cb (GtkGestureDrag *gesture,
   is_touch = (event->type == GDK_TOUCH_BEGIN ||
               gdk_device_get_source (device) == GDK_SOURCE_TOUCHSCREEN);
 
+  if ((is_touch && GTK_GESTURE (gesture) == priv->drag_gesture) ||
+      (!is_touch && GTK_GESTURE (gesture) == priv->pan_gesture))
+    {
+      gtk_gesture_set_state (GTK_GESTURE (gesture),
+                             GTK_EVENT_SEQUENCE_DENIED);
+      return;
+    }
+
   if (event->any.window == priv->handle ||
       (is_touch && initiates_touch_drag (paned, start_x, start_y)))
     {
@@ -778,27 +787,25 @@ pan_gesture_drag_begin_cb (GtkGestureDrag *gesture,
 }
 
 static void
-pan_gesture_pan_cb (GtkGesturePan   *gesture,
-                    GtkPanDirection  direction,
-                    gdouble          offset,
-                    GtkPaned        *paned)
+gesture_drag_update_cb (GtkGestureDrag   *gesture,
+                        gdouble           offset_x,
+                        gdouble           offset_y,
+                        GtkPaned         *paned)
 {
-  gdouble start_x, start_y, offset_x, offset_y;
+  gdouble start_x, start_y;
 
   paned->priv->panning = TRUE;
 
   gtk_gesture_drag_get_start_point (GTK_GESTURE_DRAG (gesture),
                                &start_x, &start_y);
-  gtk_gesture_drag_get_offset (GTK_GESTURE_DRAG (gesture),
-                               &offset_x, &offset_y);
   update_drag (paned, start_x + offset_x, start_y + offset_y);
 }
 
 static void
-pan_gesture_drag_end_cb (GtkGestureDrag *gesture,
-                         gdouble         offset_x,
-                         gdouble         offset_y,
-                         GtkPaned       *paned)
+gesture_drag_end_cb (GtkGestureDrag *gesture,
+                     gdouble         offset_x,
+                     gdouble         offset_y,
+                     GtkPaned       *paned)
 {
   if (!paned->priv->panning)
     gtk_gesture_set_state (GTK_GESTURE (gesture), GTK_EVENT_SEQUENCE_DENIED);
@@ -979,6 +986,7 @@ gtk_paned_finalize (GObject *object)
   gtk_paned_set_first_paned (paned, NULL);
 
   g_clear_object (&paned->priv->pan_gesture);
+  g_clear_object (&paned->priv->drag_gesture);
 
   g_clear_object (&paned->priv->handle_gadget);
   g_clear_object (&paned->priv->gadget);
@@ -1861,6 +1869,18 @@ update_node_state (GtkWidget *widget)
 }
 
 static void
+connect_drag_gesture_signals (GtkPaned   *paned,
+                              GtkGesture *gesture)
+{
+  g_signal_connect (gesture, "drag-begin",
+                    G_CALLBACK (gesture_drag_begin_cb), paned);
+  g_signal_connect (gesture, "drag-update",
+                    G_CALLBACK (gesture_drag_update_cb), paned);
+  g_signal_connect (gesture, "drag-end",
+                    G_CALLBACK (gesture_drag_end_cb), paned);
+}
+
+static void
 gtk_paned_init (GtkPaned *paned)
 {
   GtkPanedPrivate *priv;
@@ -1900,19 +1920,20 @@ gtk_paned_init (GtkPaned *paned)
 
   _gtk_orientable_set_style_classes (GTK_ORIENTABLE (paned));
 
+  /* Touch gesture */
   gesture = gtk_gesture_pan_new (GTK_WIDGET (paned),
                                  GTK_ORIENTATION_HORIZONTAL);
-  gtk_gesture_single_set_touch_only (GTK_GESTURE_SINGLE (gesture), FALSE);
-  g_signal_connect (gesture, "drag-begin",
-                    G_CALLBACK (pan_gesture_drag_begin_cb), paned);
-  g_signal_connect (gesture, "pan",
-                    G_CALLBACK (pan_gesture_pan_cb), paned);
-  g_signal_connect (gesture, "drag-end",
-                    G_CALLBACK (pan_gesture_drag_end_cb), paned);
+  connect_drag_gesture_signals (paned, gesture);
+  gtk_gesture_single_set_touch_only (GTK_GESTURE_SINGLE (gesture), TRUE);
   gtk_event_controller_set_propagation_phase (GTK_EVENT_CONTROLLER (gesture),
                                               GTK_PHASE_CAPTURE);
   priv->pan_gesture = gesture;
 
+  /* Pointer gesture */
+  gesture = gtk_gesture_drag_new (GTK_WIDGET (paned));
+  connect_drag_gesture_signals (paned, gesture);
+  priv->drag_gesture = gesture;
+
   widget_node = gtk_widget_get_css_node (GTK_WIDGET (paned));
   priv->gadget = gtk_css_custom_gadget_new_for_node (widget_node,
                                                      GTK_WIDGET (paned),