[gtk+] textview: Avoid usage of gdk_window_get_device_position() during DnD

[Carlos Garnacho <carlosg src gnome org>]

commit b54031d505dc4f9e65737549a92cc41900255998
Author: Carlos Garnacho <carlosg gnome org>
Date:   Thu May 21 11:58:11 2015 +0200

    textview: Avoid usage of gdk_window_get_device_position() during DnD
    
    Just use the last coordinates given on XdndPosition/drag_motion() in
    order to trigger scrolling.
    
    When running on Xwayland, the pointer position is unknown at this
    stage on the X11 side, so the coordinates given here are bogus.
    This change avoids both roundtrips and this situation.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=749679

 gtk/gtktextview.c |   51 ++++++++++++++++-----------------------------------
 1 files changed, 16 insertions(+), 35 deletions(-)
---
diff --git a/gtk/gtktextview.c b/gtk/gtktextview.c
index a247586..bbc033a 100644
--- a/gtk/gtktextview.c
+++ b/gtk/gtktextview.c
@@ -136,7 +136,9 @@ struct _GtkTextViewPrivate
   guint blink_time;  /* time in msec the cursor has blinked since last user event */
   guint im_spot_idle;
   gchar *im_module;
-  GdkDevice *dnd_device;
+
+  gint dnd_x;
+  gint dnd_y;
 
   GtkTextHandle *text_handle;
   GtkWidget *selection_bubble;
@@ -6837,33 +6839,6 @@ gtk_text_view_unselect (GtkTextView *text_view)
 }
 
 static void
-get_iter_at_pointer (GtkTextView *text_view,
-                     GdkDevice   *device,
-                     GtkTextIter *iter,
-                    gint        *x,
-                    gint        *y)
-{
-  GtkTextViewPrivate *priv;
-  gint xcoord, ycoord;
-  GdkModifierType state;
-
-  priv = text_view->priv;
-
-  gdk_window_get_device_position (priv->text_window->bin_window,
-                                  device, &xcoord, &ycoord, &state);
-
-  gtk_text_layout_get_iter_at_pixel (priv->layout,
-                                     iter,
-                                     xcoord + priv->xoffset,
-                                     ycoord + priv->yoffset);
-  if (x)
-    *x = xcoord;
-
-  if (y)
-    *y = ycoord;
-}
-
-static void
 move_mark_to_pointer_and_scroll (GtkTextView    *text_view,
                                  const gchar    *mark_name)
 {
@@ -6923,20 +6898,22 @@ drag_scan_timeout (gpointer data)
   GtkTextView *text_view;
   GtkTextViewPrivate *priv;
   GtkTextIter newplace;
-  gint x, y;
   gdouble pointer_xoffset, pointer_yoffset;
 
   text_view = GTK_TEXT_VIEW (data);
   priv = text_view->priv;
 
-  get_iter_at_pointer (text_view, priv->dnd_device, &newplace, &x, &y);
+  gtk_text_layout_get_iter_at_pixel (priv->layout,
+                                     &newplace,
+                                     priv->dnd_x + priv->xoffset,
+                                     priv->dnd_y + priv->yoffset);
 
   gtk_text_buffer_move_mark (get_buffer (text_view),
                              priv->dnd_mark,
                              &newplace);
 
-  pointer_xoffset = (gdouble) x / gdk_window_get_width (priv->text_window->bin_window);
-  pointer_yoffset = (gdouble) y / gdk_window_get_height (priv->text_window->bin_window);
+  pointer_xoffset = (gdouble) priv->dnd_x / gdk_window_get_width (priv->text_window->bin_window);
+  pointer_yoffset = (gdouble) priv->dnd_y / gdk_window_get_height (priv->text_window->bin_window);
 
   if (check_scroll (pointer_xoffset, priv->hadjustment) ||
       check_scroll (pointer_yoffset, priv->vadjustment))
@@ -7782,6 +7759,10 @@ static void
 gtk_text_view_drag_end (GtkWidget        *widget,
                         GdkDragContext   *context)
 {
+  GtkTextView *text_view;
+
+  text_view = GTK_TEXT_VIEW (widget);
+  text_view->priv->dnd_x = text_view->priv->dnd_y = -1;
 }
 
 static void
@@ -7868,8 +7849,7 @@ gtk_text_view_drag_leave (GtkWidget        *widget,
 
   gtk_text_mark_set_visible (priv->dnd_mark, FALSE);
 
-  if (priv->dnd_device)
-    priv->dnd_device = NULL;
+  priv->dnd_x = priv->dnd_y = -1;
 
   if (priv->scroll_timeout != 0)
     g_source_remove (priv->scroll_timeout);
@@ -7966,7 +7946,8 @@ gtk_text_view_drag_motion (GtkWidget        *widget,
       gtk_text_mark_set_visible (priv->dnd_mark, FALSE);
     }
 
-  priv->dnd_device = gdk_drag_context_get_device (context);
+  priv->dnd_x = x;
+  priv->dnd_y = y;
 
   if (!priv->scroll_timeout)
   {