[gtk+/multitouch-for-3.4: 31/89] gtk, scrolledwindow: Grab only after starting drag

[Carlos Garnacho <carlosg src gnome org>]

commit 22809ca81a606ddc366348ae2d4125d61b88bf46
Author: Carlos Garnacho <carlosg gnome org>
Date:   Mon Dec 5 00:17:58 2011 +0100

    gtk,scrolledwindow: Grab only after starting drag
    
    This is so the grab doesn't break the implicit grab on the
    child widget's window, which avoids that the button press and
    release are possibly sent to different windows, and after the
    grab was actually broken.

 gtk/gtkscrolledwindow.c |   33 ++++++++++++++++++---------------
 1 files changed, 18 insertions(+), 15 deletions(-)
---
diff --git a/gtk/gtkscrolledwindow.c b/gtk/gtkscrolledwindow.c
index 46ffb51..4a08d77 100644
--- a/gtk/gtkscrolledwindow.c
+++ b/gtk/gtkscrolledwindow.c
@@ -2425,9 +2425,8 @@ gtk_scrolled_window_release_captured_events (GtkScrolledWindow *scrolled_window)
   if (!priv->button_press_event)
     return FALSE;
 
-  device = gdk_event_get_device (priv->button_press_event);
-  gdk_device_ungrab (device, GDK_CURRENT_TIME);
-  gtk_device_grab_remove (GTK_WIDGET (scrolled_window), device);
+  gtk_device_grab_remove (GTK_WIDGET (scrolled_window), priv->drag_device);
+  priv->drag_device = NULL;
 
   if (priv->motion_notify_id > 0)
     {
@@ -2477,7 +2476,8 @@ gtk_scrolled_window_button_release_event (GtkWidget *widget,
   if (!child)
     return FALSE;
 
-  gdk_device_ungrab (gdk_event_get_device (_event), event->time);
+  gtk_device_grab_remove (widget, priv->drag_device);
+  priv->drag_device = NULL;
 
   if (priv->motion_notify_id > 0)
     {
@@ -2495,7 +2495,9 @@ gtk_scrolled_window_button_release_event (GtkWidget *widget,
       priv->release_timeout_id = 0;
     }
 
-  if (!priv->in_drag)
+  if (priv->in_drag)
+    gdk_device_ungrab (event->device, event->time);
+  else
     {
       /* There hasn't been scrolling at all, so just let the
        * child widget handle the events normally
@@ -2585,6 +2587,14 @@ gtk_scrolled_window_motion_notify_event (GtkWidget *widget,
         return TRUE;
     }
 
+  gdk_device_grab (priv->drag_device,
+                   gtk_widget_get_window (widget),
+                   GDK_OWNERSHIP_WINDOW,
+                   TRUE,
+                   GDK_BUTTON_RELEASE_MASK | GDK_BUTTON1_MOTION_MASK,
+                   NULL,
+                   event->time);
+
   priv->last_button_event_x_root = -TOUCH_BYPASS_CAPTURED_THRESHOLD;
   priv->last_button_event_y_root = -TOUCH_BYPASS_CAPTURED_THRESHOLD;
 
@@ -2657,7 +2667,7 @@ gtk_scrolled_window_button_press_event (GtkWidget *widget,
   gint threshold;
   GtkWidget *event_widget;
   GdkEventButton *event;
-  GdkDevice *device, *source_device;
+  GdkDevice *source_device;
   GdkInputSource source;
 
   if (_event->type != GDK_BUTTON_PRESS)
@@ -2708,15 +2718,8 @@ gtk_scrolled_window_button_press_event (GtkWidget *widget,
   if (priv->hscrollbar == event_widget || priv->vscrollbar == event_widget)
     return FALSE;
 
-  device = gdk_event_get_device (_event);
-  gdk_device_grab (device,
-                   gtk_widget_get_window (widget),
-                   GDK_OWNERSHIP_WINDOW,
-                   TRUE,
-                   GDK_BUTTON_RELEASE_MASK | GDK_BUTTON1_MOTION_MASK,
-                   NULL,
-                   event->time);
-  gtk_device_grab_add (widget, device, TRUE);
+  priv->drag_device = gdk_event_get_device (_event);
+  gtk_device_grab_add (widget, priv->drag_device, TRUE);
 
   gtk_scrolled_window_cancel_deceleration (scrolled_window);