AvalonEdit now creates an invisible Win32 caret. This is necessary for features like 'Follow text editing' in the Windows Magnifier.

git-svn-id: svn://svn.sharpdevelop.net/sharpdevelop/trunk@4901 1ccf3a8d-04fe-1044-b7c0-cef0b8235c61

src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Editing/Caret.cs

@@ -338,6 +338,7 @@ namespace ICSharpCode.AvalonEdit.Editing
 		}
 		
 		bool showScheduled;
+		bool hasWin32Caret;
 		
 		void ShowInternal()
 		{
@@ -350,7 +351,16 @@ namespace ICSharpCode.AvalonEdit.Editing
 			if (caretAdorner != null && textView != null) {
 				VisualLine visualLine = textView.GetVisualLine(position.Line);
 				if (visualLine != null) {
-					caretAdorner.Show(CalcCaretRectangle(visualLine));
+					Rect caretRect = CalcCaretRectangle(visualLine);
+					// Create Win32 caret so that Windows knows where our managed caret is. This is necessary for
+					// features like 'Follow text editing' in the Windows Magnifier.
+					if (!hasWin32Caret) {
+						hasWin32Caret = Win32.CreateCaret(textView, caretRect.Size);
+					}
+					if (hasWin32Caret) {
+						Win32.SetCaretPosition(textView, caretRect.Location - textView.ScrollOffset);
+					}
+					caretAdorner.Show(caretRect);
 				} else {
 					caretAdorner.Hide();
 				}
@@ -364,6 +374,10 @@ namespace ICSharpCode.AvalonEdit.Editing
 		{
 			Debug.WriteLine("Caret.Hide()");
 			visible = false;
+			if (hasWin32Caret) {
+				Win32.DestroyCaret();
+				hasWin32Caret = false;
+			}
 			if (caretAdorner != null) {
 				caretAdorner.Hide();
 			}

src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Editing/IReadOnlySectionProvider.cs

@@ -27,6 +27,9 @@ namespace ICSharpCode.AvalonEdit.Editing
 		/// <remarks>
 		/// All segments in the result must be within the given segment, and they must be returned in order
 		/// (e.g. if two segments are returned, EndOffset of first segment must be less than StartOffset of second segment).
+		/// 
+		/// For replacements, the last segment being returned will be replaced with the new text. If an empty list is returned,
+		/// no replacement will be done.
 		/// </remarks>
 		IEnumerable<ISegment> GetDeletableSegments(ISegment segment);
 	}

src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Utils/Win32.cs

@@ -8,6 +8,9 @@
 using System;
 using System.Runtime.InteropServices;
 using System.Security;
+using System.Windows;
+using System.Windows.Interop;
+using System.Windows.Media;
 
 namespace ICSharpCode.AvalonEdit.Utils
 {
@@ -23,11 +26,64 @@ namespace ICSharpCode.AvalonEdit.Utils
 			get { return TimeSpan.FromMilliseconds(SafeNativeMethods.GetCaretBlinkTime()); }
 		}
 		
+		/// <summary>
+		/// Creates an invisible Win32 caret for the specified Visual with the specified size (coordinates local to the owner visual).
+		/// </summary>
+		public static bool CreateCaret(Visual owner, Size size)
+		{
+			if (owner == null)
+				throw new ArgumentNullException("owner");
+			HwndSource source = PresentationSource.FromVisual(owner) as HwndSource;
+			if (source != null) {
+				Vector r = owner.PointToScreen(new Point(size.Width, size.Height)) - owner.PointToScreen(new Point(0, 0));
+				return SafeNativeMethods.CreateCaret(source.Handle, IntPtr.Zero, (int)Math.Ceiling(r.X), (int)Math.Ceiling(r.Y));
+			} else {
+				return false;
+			}
+		}
+		
+		/// <summary>
+		/// Sets the position of the caret previously created using <see cref="CreateCaret"/>. position is relative to the owner visual.
+		/// </summary>
+		public static bool SetCaretPosition(Visual owner, Point position)
+		{
+			if (owner == null)
+				throw new ArgumentNullException("owner");
+			HwndSource source = PresentationSource.FromVisual(owner) as HwndSource;
+			if (source != null) {
+				Point pointOnRootVisual = owner.TransformToAncestor(source.RootVisual).Transform(position);
+				Point pointOnHwnd = pointOnRootVisual.TransformToDevice(source.RootVisual);
+				return SafeNativeMethods.SetCaretPos((int)pointOnHwnd.X, (int)pointOnHwnd.Y);
+			} else {
+				return false;
+			}
+		}
+		
+		/// <summary>
+		/// Destroys the caret previously created using <see cref="CreateCaret"/>.
+		/// </summary>
+		public static bool DestroyCaret()
+		{
+			return SafeNativeMethods.DestroyCaret();
+		}
+		
 		[SuppressUnmanagedCodeSecurity]
 		static class SafeNativeMethods
 		{
 			[DllImport("user32.dll")]
 			public static extern int GetCaretBlinkTime();
+			
+			[DllImport("user32.dll")]
+			[return: MarshalAs(UnmanagedType.Bool)]
+			public static extern bool CreateCaret(IntPtr hWnd, IntPtr hBitmap, int nWidth, int nHeight);
+			
+			[DllImport("user32.dll")]
+			[return: MarshalAs(UnmanagedType.Bool)]
+			public static extern bool SetCaretPos(int x, int y);
+			
+			[DllImport("user32.dll")]
+			[return: MarshalAs(UnmanagedType.Bool)]
+			public static extern bool DestroyCaret();
 		}
 	}
 }