Fixed inaccuracy in GetVisualLineElementFromPosition (was incorrect by up to a half visual column)

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;
 				}

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>