From e64d24419a370fb73d42bc472703799e520eae44 Mon Sep 17 00:00:00 2001
From: Daniel Grunwald <daniel@danielgrunwald.de>
Date: Mon, 5 Sep 2011 00:49:13 +0200
Subject: [PATCH] Yet another performance improvement to AvalonEdit - we now
 use a way smaller dirty rectangle when changing only a single line.

---
 .../ICSharpCode.AvalonEdit/Rendering/TextView.cs           | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Rendering/TextView.cs b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Rendering/TextView.cs
index 8f6b72339b..db13efe534 100644
--- a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Rendering/TextView.cs
+++ b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Rendering/TextView.cs
@@ -1158,8 +1158,11 @@ namespace ICSharpCode.AvalonEdit.Rendering
 		{
 			Point pos = new Point(-scrollOffset.X, -clippedPixelsOnTop);
 			foreach (VisualLineDrawingVisual visual in visuals) {
-				visual.Transform = new TranslateTransform(pos.X, pos.Y);
-				visual.Transform.Freeze();
+				TranslateTransform t = visual.Transform as TranslateTransform;
+				if (t == null || t.X != pos.X || t.Y != pos.Y) {
+					visual.Transform = new TranslateTransform(pos.X, pos.Y);
+					visual.Transform.Freeze();
+				}
 				pos.Y += visual.Height;
 			}
 		}