[meld] diffmap: Update Diffmap to match its scrollbar's width

[Kai Willadsen <kaiw src gnome org>]

commit b7da4b58f28294169706b26c38f426f2df86a041
Author: Kai Willadsen <kai willadsen gmail com>
Date:   Mon Dec 30 07:36:07 2013 +1000

    diffmap: Update Diffmap to match its scrollbar's width

 meld/diffmap.py |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/meld/diffmap.py b/meld/diffmap.py
index 9cbb35b..77492cb 100644
--- a/meld/diffmap.py
+++ b/meld/diffmap.py
@@ -38,6 +38,7 @@ class DiffMap(Gtk.DrawingArea):
         self._scroll_y = 0
         self._scroll_height = 0
         self._setup = False
+        self._width = 10
 
     def setup(self, scrollbar, change_chunk_fn, color_map):
         for (o, h) in self._handlers:
@@ -100,7 +101,8 @@ class DiffMap(Gtk.DrawingArea):
     def on_scrollbar_size_allocate(self, scrollbar, allocation):
         self._scroll_y = allocation.y
         self._scroll_height = allocation.height
-        self.queue_draw()
+        self._width = allocation.width
+        self.queue_resize()
 
     def do_draw(self, context):
         if not self._setup:
@@ -155,4 +157,4 @@ class DiffMap(Gtk.DrawingArea):
         return False
 
     def do_get_preferred_width(self):
-        return 20, 20
+        return self._width, self._width