prepare DnD for copying processor state

diff --git a/libs/gtkmm2ext/gtkmm2ext/dndvbox.h b/libs/gtkmm2ext/gtkmm2ext/dndvbox.h
index aba413b352af25b0415f8b6fc6537943ccdc928d..1d4e43c31b1657cfbc158fae57891b19c1119f8a 100644 (file)
--- a/libs/gtkmm2ext/gtkmm2ext/dndvbox.h
+++ b/libs/gtkmm2ext/gtkmm2ext/dndvbox.h
@@ -46,6 +46,8 @@ public:
        virtual bool is_selectable () const = 0;
 
        virtual bool drag_data_get (Glib::RefPtr<Gdk::DragContext> const, Gtk::SelectionData &) { return false; }
+
+       virtual bool can_copy_state (DnDVBoxChild*) const = 0;
 };
 
 /** A VBox whose contents can be dragged and dropped */
@@ -59,6 +61,7 @@ public:
                , _drag_icon (0)
                , _expecting_unwanted_button_event (false)
                , _placeholder (0)
+               , _drag_child (0)
        {
 
                add (_internal_vbox);
@@ -75,7 +78,7 @@ public:
 
                _internal_vbox.show ();
 
-               drag_dest_set (_targets);
+               drag_dest_set (_targets, Gtk::DEST_DEFAULT_ALL, Gdk::DragAction (Gdk::ACTION_COPY | Gdk::ACTION_MOVE | Gdk::ACTION_LINK));
                signal_drag_data_received().connect (mem_fun (*this, &DnDVBox::drag_data_received));
        }
 
@@ -440,21 +443,33 @@ private:
                return n;
        }
 
-       bool drag_motion (Glib::RefPtr<Gdk::DragContext> const &, int /*x*/, int y, guint)
+       bool drag_motion (Glib::RefPtr<Gdk::DragContext> const & ctx, int /*x*/, int y, guint tme)
        {
                if (_children.empty ()) {
                        return false;
                }
 
                T* before;
-               T* at;
+               T* at = NULL;
                T* after;
 
                /* decide where we currently are */
                double const c = get_children_around_position (y, &before, &at, &after);
 
                /* whether we're in the top or bottom half of the child that we're over */
-               bool top_half = (c - int (c)) < 0.5;
+               bool top_half = (c - int (c)) < .5;
+               bool bottom_half = !top_half;
+
+               if (_drag_source != this /* re-order */
+                               && _drag_source && at
+                               && _drag_source->_drag_child
+                               && _drag_source->selection ().size () == 1
+                               && at != _drag_source->_drag_child // can't happen or can it?
+                               && at->can_copy_state (_drag_source->_drag_child))
+               {
+                       top_half = (c - int (c)) < 0.33;
+                       bottom_half = (c - int (c)) > 0.8; // increase area >> 0.66; plugin below will move, or there's space
+               }
 
                /* Note that when checking on whether to remove a placeholder, we never do
                   so if _drag_child is 0 as this means that the child being dragged is
@@ -468,14 +483,25 @@ private:
                        return false;
                }
 
-               if (!top_half && _drag_child && (at == _drag_child || after == _drag_child)) {
+               if (bottom_half && _drag_child && (at == _drag_child || after == _drag_child)) {
                        /* dropping here would have no effect, so remove the visual cue */
                        remove_placeholder ();
                        return false;
                }
 
-               create_or_update_placeholder (c);
-               return false;
+               printf ("%x\n", ctx->get_suggested_action());
+               if (top_half || bottom_half) {
+                       create_or_update_placeholder (c);
+                       if (_drag_source == this /* re-order */) {
+                               ctx->drag_status (Gdk::ACTION_MOVE, tme);
+                       } else {
+                               ctx->drag_status (Gdk::ACTION_COPY, tme);
+                       }
+               } else {
+                       ctx->drag_status (Gdk::ACTION_LINK, tme);
+                       remove_placeholder ();
+               }
+               return true;
        }
 
        void drag_leave (Glib::RefPtr<Gdk::DragContext> const &, guint)