master c1a6aa0c3e: Fix xwidget smooth scrolling when the default pointer is not a touchpad

[Po Lu]

branch: master
commit c1a6aa0c3eb1029e3f7f5c3b227d7952bee775b8
Author: Po Lu <luangruo@yahoo.com>
Commit: Po Lu <luangruo@yahoo.com>

    Fix xwidget smooth scrolling when the default pointer is not a touchpad
    
    * xwidget.c (find_suitable_pointer): New argument
    `need_smooth'.  Try to find a touchpad if that is set.
    (xwidget_button_1, xwidget_button, xwidget_motion_notify)
    (xwidget_scroll, xwidget_pinch, xw_notify_virtual_upwards_until)
    (xw_notify_virtual_downwards_until):
    (xw_maybe_synthesize_crossing):
    (xwidget_motion_or_crossing, synthesize_focus_in_event): Set
    parameter accordingly.
---
 src/xwidget.c | 67 +++++++++++++++++++++++++++++++++++++++++++----------------
 1 file changed, 49 insertions(+), 18 deletions(-)

diff --git a/src/xwidget.c b/src/xwidget.c
index 71bc350429..8bdfab02fd 100644
--- a/src/xwidget.c
+++ b/src/xwidget.c
@@ -857,15 +857,34 @@ to_embedder (GdkWindow *window, double x, double y,
 }
 
 static GdkDevice *
-find_suitable_pointer (struct frame *f)
+find_suitable_pointer (struct frame *f, bool need_smooth)
 {
   GdkSeat *seat = gdk_display_get_default_seat
     (gtk_widget_get_display (FRAME_GTK_WIDGET (f)));
+  GList *devices, *tem;
+  GdkDevice *device;
 
   if (!seat)
     return NULL;
 
-  return gdk_seat_get_pointer (seat);
+  devices = gdk_seat_get_slaves (seat, GDK_SEAT_CAPABILITY_ALL_POINTING);
+  device = NULL;
+  tem = NULL;
+
+  if (need_smooth)
+    {
+      for (tem = devices; tem; tem = tem->next)
+       {
+         device = GDK_DEVICE (tem->data);
+
+         if (gdk_device_get_source (device) == GDK_SOURCE_TOUCHPAD)
+           break;
+       }
+    }
+
+  g_list_free (devices);
+
+  return !tem ? gdk_seat_get_pointer (seat) : device;
 }
 
 static GdkDevice *
@@ -1196,7 +1215,7 @@ xwidget_button_1 (struct xwidget_view *view,
   xg_event->button.button = button;
   xg_event->button.state = modifier_state;
   xg_event->button.time = time;
-  xg_event->button.device = find_suitable_pointer (view->frame);
+  xg_event->button.device = find_suitable_pointer (view->frame, false);
 
   gtk_main_do_event (xg_event);
   gdk_event_free (xg_event);
@@ -1242,7 +1261,8 @@ xwidget_button_1 (struct xwidget_view *view,
          xg_event->crossing.detail = GDK_NOTIFY_ANCESTOR;
          xg_event->crossing.mode = GDK_CROSSING_UNGRAB;
          xg_event->crossing.window = g_object_ref (target_window);
-         gdk_event_set_device (xg_event, find_suitable_pointer (view->frame));
+         gdk_event_set_device (xg_event,
+                               find_suitable_pointer (view->frame, false));
 
          gtk_main_do_event (xg_event);
          gdk_event_free (xg_event);
@@ -1264,7 +1284,8 @@ xwidget_button_1 (struct xwidget_view *view,
              xg_event->crossing.mode = GDK_CROSSING_UNGRAB;
              xg_event->crossing.window = g_object_ref (toplevel);
 
-             gdk_event_set_device (xg_event, find_suitable_pointer 
(view->frame));
+             gdk_event_set_device (xg_event,
+                                   find_suitable_pointer (view->frame, false));
              gtk_main_do_event (xg_event);
              gdk_event_free (xg_event);
            }
@@ -1323,7 +1344,8 @@ xwidget_button (struct xwidget_view *view,
          else
            xg_event->scroll.direction = GDK_SCROLL_RIGHT;
 
-         xg_event->scroll.device = find_suitable_pointer (view->frame);
+         xg_event->scroll.device = find_suitable_pointer (view->frame,
+                                                          false);
 
          xg_event->scroll.x = x;
          xg_event->scroll.x_root = x;
@@ -1387,7 +1409,7 @@ xwidget_motion_notify (struct xwidget_view *view,
   xg_event->motion.y_root = root_y;
   xg_event->motion.time = time;
   xg_event->motion.state = state;
-  xg_event->motion.device = find_suitable_pointer (view->frame);
+  xg_event->motion.device = find_suitable_pointer (view->frame, false);
 
   g_object_ref (xg_event->any.window);
 
@@ -1434,7 +1456,7 @@ xwidget_scroll (struct xwidget_view *view, double x, 
double y,
   xg_event->scroll.state = state;
   xg_event->scroll.delta_x = dx;
   xg_event->scroll.delta_y = dy;
-  xg_event->scroll.device = find_suitable_pointer (view->frame);
+  xg_event->scroll.device = find_suitable_pointer (view->frame, true);
   xg_event->scroll.is_stop = stop_p;
 
   g_object_ref (xg_event->any.window);
@@ -1499,7 +1521,7 @@ xwidget_pinch (struct xwidget_view *view, 
XIGesturePinchEvent *xev)
       break;
     }
 
-  gdk_event_set_device (xg_event, find_suitable_pointer (view->frame));
+  gdk_event_set_device (xg_event, find_suitable_pointer (view->frame, false));
 
   g_object_ref (xg_event->any.window);
   gtk_main_do_event (xg_event);
@@ -1624,7 +1646,8 @@ xw_notify_virtual_upwards_until (struct xwidget_view *xv,
     {
       xg_event = gdk_event_new (type);
 
-      gdk_event_set_device (xg_event, find_suitable_pointer (xv->frame));
+      gdk_event_set_device (xg_event,
+                           find_suitable_pointer (xv->frame, false));
       window_coords_from_toplevel (tem, toplevel, x, y, &cx, &cy);
       xg_event->crossing.x = cx;
       xg_event->crossing.y = cy;
@@ -1670,7 +1693,8 @@ xw_notify_virtual_downwards_until (struct xwidget_view 
*xv,
       tem = it->data;
       xg_event = gdk_event_new (type);
 
-      gdk_event_set_device (xg_event, find_suitable_pointer (xv->frame));
+      gdk_event_set_device (xg_event,
+                           find_suitable_pointer (xv->frame, false));
       window_coords_from_toplevel (tem, toplevel, x, y, &cx, &cy);
       xg_event->crossing.x = cx;
       xg_event->crossing.y = cy;
@@ -1775,7 +1799,8 @@ xw_maybe_synthesize_crossing (struct xwidget_view *view,
          xg_event->crossing.detail = GDK_NOTIFY_ANCESTOR;
          xg_event->crossing.mode = exit_crossing;
          xg_event->crossing.window = g_object_ref (view->last_crossing_window);
-         gdk_event_set_device (xg_event, find_suitable_pointer (view->frame));
+         gdk_event_set_device (xg_event,
+                               find_suitable_pointer (view->frame, false));
 
          gtk_main_do_event (xg_event);
          gdk_event_free (xg_event);
@@ -1839,7 +1864,8 @@ xw_maybe_synthesize_crossing (struct xwidget_view *view,
                                         exit_crossing);
 
       xg_event = gdk_event_new (GDK_LEAVE_NOTIFY);
-      gdk_event_set_device (xg_event, find_suitable_pointer (view->frame));
+      gdk_event_set_device (xg_event,
+                           find_suitable_pointer (view->frame, false));
       window_coords_from_toplevel (last_crossing, toplevel,
                                   x, y, &cx, &cy);
       xg_event->crossing.x = cx;
@@ -1867,7 +1893,8 @@ xw_maybe_synthesize_crossing (struct xwidget_view *view,
                                           entry_crossing);
 
       xg_event = gdk_event_new (GDK_ENTER_NOTIFY);
-      gdk_event_set_device (xg_event, find_suitable_pointer (view->frame));
+      gdk_event_set_device (xg_event,
+                           find_suitable_pointer (view->frame, false));
       window_coords_from_toplevel (current_window, toplevel,
                                   x, y, &cx, &cy);
       xg_event->crossing.x = cx;
@@ -1970,7 +1997,8 @@ xwidget_motion_or_crossing (struct xwidget_view *view, 
const XEvent *event)
          xg_event->motion.y_root = event->xmotion.y_root;
          xg_event->motion.time = event->xmotion.time;
          xg_event->motion.state = event->xmotion.state;
-         xg_event->motion.device = find_suitable_pointer (view->frame);
+         xg_event->motion.device
+           = find_suitable_pointer (view->frame, false);
        }
       else
        {
@@ -2017,7 +2045,8 @@ xwidget_motion_or_crossing (struct xwidget_view *view, 
const XEvent *event)
          return;
        }
 
-      gdk_event_set_device (xg_event, find_suitable_pointer (view->frame));
+      gdk_event_set_device (xg_event,
+                           find_suitable_pointer (view->frame, false));
     }
 #endif
   else
@@ -2046,7 +2075,8 @@ xwidget_motion_or_crossing (struct xwidget_view *view, 
const XEvent *event)
       xg_event->crossing.x_root = event->xcrossing.x_root;
       xg_event->crossing.y_root = event->xcrossing.y_root;
       xg_event->crossing.focus = event->xcrossing.focus;
-      gdk_event_set_device (xg_event, find_suitable_pointer (view->frame));
+      gdk_event_set_device (xg_event,
+                           find_suitable_pointer (view->frame, false));
     }
 
   gtk_main_do_event (xg_event);
@@ -2072,7 +2102,8 @@ synthesize_focus_in_event (GtkWidget *offscreen_window)
 
   if (FRAME_WINDOW_P (SELECTED_FRAME ()))
     gdk_event_set_device (focus_event,
-                         find_suitable_pointer (SELECTED_FRAME ()));
+                         find_suitable_pointer (SELECTED_FRAME (),
+                                                false));
 
   g_object_ref (wnd);