From fd7ac62ca5a44f68b6701f21d9296cb19f0ebdc6 Mon Sep 17 00:00:00 2001
From: Paul Davis <paul@linuxaudiosystems.com>
Date: Thu, 25 Apr 2013 09:48:38 -0400
Subject: [PATCH] don't invalidate image cache for every regionr esize, only
 region start changes

---
 libs/canvas/wave_view.cc | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/libs/canvas/wave_view.cc b/libs/canvas/wave_view.cc
index f39dca7594..ac45c2bc7c 100644
--- a/libs/canvas/wave_view.cc
+++ b/libs/canvas/wave_view.cc
@@ -421,8 +421,17 @@ WaveView::region_resized ()
 
 	_pre_change_bounding_box = _bounding_box;
 
-	_region_start = _region->start();
-	invalidate_whole_cache ();
+	frameoffset_t s = _region->start();
+
+	if (s != _region_start) {
+		/* if the region start changes, the information we have 
+		   in the image cache is out of date and not useful
+		   since it will fragmented into little pieces. invalidate
+		   the cache.
+		*/
+		_region_start = _region->start();
+		invalidate_whole_cache ();
+	}
 
 	_bounding_box_dirty = true;
 	compute_bounding_box ();