[pitivi] Highlight separator while drag'n'drop

[Jean-FranÃois Fortin Tam <jfft src gnome org>]

commit 6bf5e6496a29396f2bd3fcff954cc3d8493f1220
Author: Paul Lange <palango gmx de>
Date:   Sun Jul 15 19:54:25 2012 +0200

    Highlight separator while drag'n'drop

 pitivi/timeline/layer.py    |   33 ++++++++++++++++++++++++++-------
 pitivi/timeline/timeline.py |   30 ++++++++++++++++++++++++++++--
 2 files changed, 54 insertions(+), 9 deletions(-)
---
diff --git a/pitivi/timeline/layer.py b/pitivi/timeline/layer.py
index e1b0fd1..37791c4 100644
--- a/pitivi/timeline/layer.py
+++ b/pitivi/timeline/layer.py
@@ -47,9 +47,9 @@ class BaseLayerControl(gtk.VBox, Loggable):
         self.layer = layer
         self._selected = False
 
-        # get the default colour for the current theme
+        # get the default color for the current theme
         self.UNSELECTED_COLOR = self.rc_get_style().bg[gtk.STATE_NORMAL]
-        # use base instead of bg colours so that we get the lighter colour
+        # use base instead of bg colors so that we get the lighter color
         # that is used for list items in TreeView.
         self.SELECTED_COLOR = self.rc_get_style().base[gtk.STATE_SELECTED]
 
@@ -256,7 +256,7 @@ class BaseLayerControl(gtk.VBox, Loggable):
         -2 = first and last item -> all disabled
         """
         for menu_item in (self.layer_up, self.layer_first,
-                              self.layer_down, self.layer_last):
+                          self.layer_down, self.layer_last):
             menu_item.set_sensitive(True)
 
         if position == -2 or position == 0:
@@ -267,6 +267,17 @@ class BaseLayerControl(gtk.VBox, Loggable):
             self.layer_down.set_sensitive(False)
             self.layer_last.set_sensitive(False)
 
+    def setSeparatorHighlight(self, highlighted):
+        """
+        Sets if the Separator should be highlighted
+
+        Used for visual drag'n'drop feedback
+        """
+        if highlighted:
+            self.sep.modify_bg(gtk.STATE_NORMAL, self.SELECTED_COLOR)
+        else:
+            self.sep.modify_bg(gtk.STATE_NORMAL, self.UNSELECTED_COLOR)
+
 
 class VideoLayerControl(BaseLayerControl):
     """
@@ -353,10 +364,18 @@ class TwoStateButton(gtk.Button):
         self.emit("changed-state", self._state)
 
 
-class SpacedSeparator(gtk.VBox):
+class SpacedSeparator(gtk.EventBox):
+    """
+    A Separator with vertical spacing
+
+    Inherits from EventBox since we want to change background color
+    """
 
     def __init__(self):
-        gtk.VBox.__init__(self)
+        gtk.EventBox.__init__(self)
+
+        self.box = gtk.VBox()
+        self.box.add(gtk.HSeparator())
+        self.box.props.border_width = 6
 
-        self.add(gtk.HSeparator())
-        self.props.border_width = 6
+        self.add(self.box)
diff --git a/pitivi/timeline/timeline.py b/pitivi/timeline/timeline.py
index 87cd9f2..842883c 100644
--- a/pitivi/timeline/timeline.py
+++ b/pitivi/timeline/timeline.py
@@ -513,6 +513,7 @@ class TimelineControls(gtk.VBox, Loggable):
 
         # drag'n' drop
         self.connect("drag_data_received", self._dragDataReceivedCb)
+        self.connect("drag_motion", self._dragMotionCb)
         self.drag_dest_set(gtk.DEST_DEFAULT_MOTION |
                              gtk.DEST_DEFAULT_DROP,
                              [LAYER_CONTROL_TUPLE], gtk.gdk.ACTION_MOVE)
@@ -750,6 +751,30 @@ class TimelineControls(gtk.VBox, Loggable):
         widget = self.getControlFromId(int(selection.data))
         widget_type = type(widget)
 
+        for child in self.get_children():
+            child.setSeparatorHighlight(False)
+
+        self.moveControlWidget(widget, self._getIndexForPosition(y))
+
+    def _dragMotionCb(self, widget, context, x, y, timestamp):
+        """
+        Highlight separator where control would go when dropping
+        """
+        index = self._getIndexForPosition(y)
+
+        for child in self.get_children():
+            child.setSeparatorHighlight(False)
+
+        # control would go in first position
+        if index == 0:
+            pass
+        else:
+            self.get_children()[index - 1].setSeparatorHighlight(True)
+
+    def _getIndexForPosition(self, y):
+        """
+        Calculates the new index for a dragged layer
+        """
         counter = 0
         index = 0
 
@@ -757,12 +782,13 @@ class TimelineControls(gtk.VBox, Loggable):
         for child in self.get_children():
             next = counter + child.getHeight()
             if y >= counter and y < next:
-                self.moveControlWidget(widget, index)
-                return
+                return index
 
             counter = next
             index += 1
 
+        return index
+
     def moveControlWidget(self, control, index):
         """
         Moves control to the given index and cares for moving the linked layer