[gtk+] wayland: Separate touch pointer emulation into its own master pointer

[Carlos Garnacho <carlosg src gnome org>]

commit 04ecffa238fd5fbcb98eb40e7976f357ddb68305
Author: Carlos Garnacho <carlosg gnome org>
Date:   Thu Oct 8 16:41:35 2015 +0200

    wayland: Separate touch pointer emulation into its own master pointer
    
    The common GDK code accounts for "pointer emulating" touch sequences to be
    synchronized with the pointer position by the windowing system.
    
    However on Wayland pointer and touch are completely independent, the backend
    attempts to implement pointer emulation, but doesn't account for the
    possible crossing events happening when the user switches from pointer to
    touch or the opposite.
    
    In order to fix this, and to ensure we don't have to interact with the
    master pointer (which backs the wl_pointer), separate the touch interface
    to have its own master pointer, and ensure crossing events are emitted on
    it, so the picture of an "emulated pointer" is complete above the backend.
    
    Inspired in a former patch by Jonny Lamb <jonnylamb gnome org>
    
    https://bugzilla.gnome.org/show_bug.cgi?id=750845

 gdk/wayland/gdkdevice-wayland.c |   74 +++++++++++++++++++++++++++++++++++++-
 1 files changed, 72 insertions(+), 2 deletions(-)
---
diff --git a/gdk/wayland/gdkdevice-wayland.c b/gdk/wayland/gdkdevice-wayland.c
index 157630f..60e209d 100644
--- a/gdk/wayland/gdkdevice-wayland.c
+++ b/gdk/wayland/gdkdevice-wayland.c
@@ -69,6 +69,7 @@ struct _GdkWaylandDeviceData
   GdkDevice *master_keyboard;
   GdkDevice *pointer;
   GdkDevice *keyboard;
+  GdkDevice *touch_master;
   GdkDevice *touch;
   GdkCursor *cursor;
   GdkKeymap *keymap;
@@ -118,6 +119,7 @@ struct _GdkWaylandDevice
 {
   GdkDevice parent_instance;
   GdkWaylandDeviceData *device;
+  GdkWaylandTouchData *emulating_touch; /* Only used on wd->touch_master */
 };
 
 struct _GdkWaylandDeviceClass
@@ -405,6 +407,35 @@ emulate_crossing (GdkWindow       *window,
 }
 
 static void
+emulate_touch_crossing (GdkWindow           *window,
+                        GdkWindow           *subwindow,
+                        GdkDevice           *device,
+                        GdkDevice           *source,
+                        GdkWaylandTouchData *touch,
+                        GdkEventType         type,
+                        GdkCrossingMode      mode,
+                        guint32              time_)
+{
+  GdkEvent *event;
+
+  event = gdk_event_new (type);
+  event->crossing.window = window ? g_object_ref (window) : NULL;
+  event->crossing.subwindow = subwindow ? g_object_ref (subwindow) : NULL;
+  event->crossing.time = time_;
+  event->crossing.mode = mode;
+  event->crossing.detail = GDK_NOTIFY_NONLINEAR;
+  gdk_event_set_device (event, device);
+  gdk_event_set_source_device (event, source);
+
+  event->crossing.x = touch->x;
+  event->crossing.y = touch->y;
+  event->crossing.x_root = event->crossing.x;
+  event->crossing.y_root = event->crossing.y;
+
+  _gdk_wayland_display_deliver_event (gdk_window_get_display (window), event);
+}
+
+static void
 emulate_focus (GdkWindow *window,
                GdkDevice *device,
                gboolean   focus_in,
@@ -1555,7 +1586,7 @@ _create_touch_event (GdkWaylandDeviceData *device,
 
   event = gdk_event_new (evtype);
   event->touch.window = g_object_ref (touch->window);
-  gdk_event_set_device (event, device->master_pointer);
+  gdk_event_set_device (event, device->touch_master);
   gdk_event_set_source_device (event, device->touch);
   event->touch.time = time;
   event->touch.state = device->button_modifiers | device->key_modifiers;
@@ -1604,6 +1635,14 @@ touch_handle_down (void              *data,
 
   event = _create_touch_event (device, touch, GDK_TOUCH_BEGIN, time);
 
+  if (touch->initial_touch)
+    {
+      emulate_touch_crossing (touch->window, NULL,
+                              device->touch_master, device->touch, touch,
+                              GDK_ENTER_NOTIFY, GDK_CROSSING_NORMAL, time);
+      GDK_WAYLAND_DEVICE(device->touch_master)->emulating_touch = touch;
+    }
+
   GDK_NOTE (EVENTS,
             g_message ("touch begin %f %f", event->touch.x, event->touch.y));
 
@@ -1631,6 +1670,15 @@ touch_handle_up (void            *data,
             g_message ("touch end %f %f", event->touch.x, event->touch.y));
 
   _gdk_wayland_display_deliver_event (device->display, event);
+
+  if (touch->initial_touch)
+    {
+      emulate_touch_crossing (touch->window, NULL,
+                              device->touch_master, device->touch, touch,
+                              GDK_LEAVE_NOTIFY, GDK_CROSSING_NORMAL, time);
+      GDK_WAYLAND_DEVICE(device->touch_master)->emulating_touch = NULL;
+    }
+
   gdk_wayland_device_remove_touch (device, id);
 }
 
@@ -2049,6 +2097,22 @@ seat_handle_capabilities (void                    *data,
       wl_touch_set_user_data (device->wl_touch, device);
       wl_touch_add_listener (device->wl_touch, &touch_listener, device);
 
+      device->touch_master = g_object_new (GDK_TYPE_WAYLAND_DEVICE,
+                                           "name", "Wayland Touch Master Pointer",
+                                           "type", GDK_DEVICE_TYPE_MASTER,
+                                           "input-source", GDK_SOURCE_MOUSE,
+                                           "input-mode", GDK_MODE_SCREEN,
+                                           "has-cursor", TRUE,
+                                           "display", device->display,
+                                           "device-manager", device->device_manager,
+                                           NULL);
+      GDK_WAYLAND_DEVICE (device->touch_master)->device = device;
+      _gdk_device_set_associated_device (device->touch_master, device->master_keyboard);
+
+      device_manager->devices =
+        g_list_prepend (device_manager->devices, device->touch_master);
+      g_signal_emit_by_name (device_manager, "device-added", device->touch_master);
+
       device->touch = g_object_new (GDK_TYPE_WAYLAND_DEVICE,
                                     "name", "Wayland Touch",
                                     "type", GDK_DEVICE_TYPE_SLAVE,
@@ -2058,7 +2122,7 @@ seat_handle_capabilities (void                    *data,
                                     "display", device->display,
                                     "device-manager", device->device_manager,
                                     NULL);
-      _gdk_device_set_associated_device (device->touch, device->master_pointer);
+      _gdk_device_set_associated_device (device->touch, device->touch_master);
       GDK_WAYLAND_DEVICE (device->touch)->device = device;
 
       device_manager->devices =
@@ -2070,13 +2134,19 @@ seat_handle_capabilities (void                    *data,
     {
       wl_touch_release (device->wl_touch);
       device->wl_touch = NULL;
+      _gdk_device_set_associated_device (device->touch_master, NULL);
       _gdk_device_set_associated_device (device->touch, NULL);
 
       device_manager->devices =
+        g_list_remove (device_manager->devices, device->touch_master);
+      device_manager->devices =
         g_list_remove (device_manager->devices, device->touch);
 
+      g_signal_emit_by_name (device_manager, "device-removed", device->touch_master);
       g_signal_emit_by_name (device_manager, "device-removed", device->touch);
+      g_object_unref (device->touch_master);
       g_object_unref (device->touch);
+      device->touch_master = NULL;
       device->touch = NULL;
     }
 }