From 4f2269751fec54c9408d60651b874f22ce200703 Mon Sep 17 00:00:00 2001
From: Daniel Grunwald <daniel@danielgrunwald.de>
Date: Tue, 21 Sep 2010 14:48:29 +0200
Subject: [PATCH] Fixed inaccuracy in GetVisualLineElementFromPosition (was
 incorrect by up to a half visual column)

---
 .../ICSharpCode.AvalonEdit/Rendering/TextView.cs     |  4 ++--
 .../ICSharpCode.AvalonEdit/Rendering/VisualLine.cs   | 12 ++++++++++++
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Rendering/TextView.cs b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Rendering/TextView.cs
index ed5338030b..ea3e74fe00 100644
--- a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Rendering/TextView.cs
+++ b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Rendering/TextView.cs
@@ -1307,10 +1307,10 @@ namespace ICSharpCode.AvalonEdit.Rendering
 		{
 			VisualLine vl = GetVisualLineFromVisualTop(visualPosition.Y);
 			if (vl != null) {
-				int column = vl.GetVisualColumn(visualPosition);
+				int column = vl.GetVisualColumnFloor(visualPosition);
 //				Debug.WriteLine(vl.FirstDocumentLine.LineNumber + " vc " + column);
 				foreach (VisualLineElement element in vl.Elements) {
-					if (element.VisualColumn + element.VisualLength < column)
+					if (element.VisualColumn + element.VisualLength <= column)
 						continue;
 					return element;
 				}
diff --git a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Rendering/VisualLine.cs b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Rendering/VisualLine.cs
index fb153a8366..29ff6c1629 100644
--- a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Rendering/VisualLine.cs
+++ b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Rendering/VisualLine.cs
@@ -306,6 +306,7 @@ namespace ICSharpCode.AvalonEdit.Rendering
 		
 		/// <summary>
 		/// Gets the visual column from a document position (relative to top left of the document).
+		/// If the user clicks between two visual columns, rounds to the nearest column.
 		/// </summary>
 		public int GetVisualColumn(Point point)
 		{
@@ -314,6 +315,17 @@ namespace ICSharpCode.AvalonEdit.Rendering
 			return ch.FirstCharacterIndex + ch.TrailingLength;
 		}
 		
+		/// <summary>
+		/// Gets the visual column from a document position (relative to top left of the document).
+		/// If the user clicks between two visual columns, returns the first of those columns.
+		/// </summary>
+		public int GetVisualColumnFloor(Point point)
+		{
+			TextLine textLine = GetTextLineByVisualYPosition(point.Y);
+			CharacterHit ch = textLine.GetCharacterHitFromDistance(point.X);
+			return ch.FirstCharacterIndex;
+		}
+		
 		/// <summary>
 		/// Gets whether the visual line was disposed.
 		/// </summary>