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path: root/Software/Visual_Studio/Scripting/Tango.Scripting.Editors/Editing/CaretNavigationCommandHandler.cs

blob: d1b812b66227aaa1e13bc857d37a1e03189b664d (plain)

pre { line-height: 125%; } td.linenos .normal { color: inherit; background-color: transparent; padding-left: 5px; padding-right: 5px; } span.linenos { color: inherit; background-color: transparent; padding-left: 5px; padding-right: 5px; } td.linenos .special { color: #000000; background-color: #ffffc0; padding-left: 5px; padding-right: 5px; } span.linenos.special { color: #000000; background-color: #ffffc0; padding-left: 5px; padding-right: 5px; } .highlight .hll { background-color: #ffffcc } .highlight .c { color: #888888 } /* Comment */ .highlight .err { color: #a61717; background-color: #e3d2d2 } /* Error */ .highlight .k { color: #008800; font-weight: bold } /* Keyword */ .highlight .ch { color: #888888 } /* Comment.Hashbang */ .highlight .cm { color: #888888 } /* Comment.Multiline */ .highlight .cp { color: #cc0000; font-weight: bold } /* Comment.Preproc */ .highlight .cpf { color: #888888 } /* Comment.PreprocFile */ .highlight .c1 { color: #888888 } /* Comment.Single */ .highlight .cs { color: #cc0000; font-weight: bold; background-color: #fff0f0 } /* Comment.Special */ .highlight .gd { color: #000000; background-color: #ffdddd } /* Generic.Deleted */ .highlight .ge { font-style: italic } /* Generic.Emph */ .highlight .ges { font-weight: bold; font-style: italic } /* Generic.EmphStrong */ .highlight .gr { color: #aa0000 } /* Generic.Error */ .highlight .gh { color: #333333 } /* Generic.Heading */ .highlight .gi { color: #000000; background-color: #ddffdd } /* Generic.Inserted */ .highlight .go { color: #888888 } /* Generic.Output */ .highlight .gp { color: #555555 } /* Generic.Prompt */ .highlight .gs { font-weight: bold } /* Generic.Strong */ .highlight .gu { color: #666666 } /* Generic.Subheading */ .highlight .gt { color: #aa0000 } /* Generic.Traceback */ .highlight .kc { color: #008800; font-weight: bold } /* Keyword.Constant */ .highlight .kd { color: #008800; font-weight: bold } /* Keyword.Declaration */ .highlight .kn { color: #008800; font-weight: bold } /* Keyword.Namespace */ .highlight .kp { color: #008800 } /* Keyword.Pseudo */ .highlight .kr { color: #008800; font-weight: bold } /* Keyword.Reserved */ .highlight .kt { color: #888888; font-weight: bold } /* Keyword.Type */ .highlight .m { color: #0000DD; font-weight: bold } /* Literal.Number */ .highlight .s { color: #dd2200; background-color: #fff0f0 } /* Literal.String */ .highlight .na { color: #336699 } /* Name.Attribute */ .highlight .nb { color: #003388 } /* Name.Builtin */ .highlight .nc { color: #bb0066; font-weight: bold } /* Name.Class */ .highlight .no { color: #003366; font-weight: bold } /* Name.Constant */ .highlight .nd { color: #555555 } /* Name.Decorator */ .highlight .ne { color: #bb0066; font-weight: bold } /* Name.Exception */ .highlight .nf { color: #0066bb; font-weight: bold } /* Name.Function */ .highlight .nl { color: #336699; font-style: italic } /* Name.Label */ .highlight .nn { color: #bb0066; font-weight: bold } /* Name.Namespace */ .highlight .py { color: #336699; font-weight: bold } /* Name.Property */ .highlight .nt { color: #bb0066; font-weight: bold } /* Name.Tag */ .highlight .nv { color: #336699 } /* Name.Variable */ .highlight .ow { color: #008800 } /* Operator.Word */ .highlight .w { color: #bbbbbb } /* Text.Whitespace */ .highlight .mb { color: #0000DD; font-weight: bold } /* Literal.Number.Bin */ .highlight .mf { color: #0000DD; font-weight: bold } /* Literal.Number.Float */ .highlight .mh { color: #0000DD; font-weight: bold } /* Literal.Number.Hex */ .highlight .mi { color: #0000DD; font-weight: bold } /* Literal.Number.Integer */ .highlight .mo { color: #0000DD; font-weight: bold } /* Literal.Number.Oct */ .highlight .sa { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Affix */ .highlight .sb { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Backtick */ .highlight .sc { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Char */ .highlight .dl { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Delimiter */ .highlight .sd { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Doc */ .highlight .s2 { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Double */ .highlight .se { color: #0044dd; background-color: #fff0f0 } /* Literal.String.Escape */ .highlight .sh { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Heredoc */ .highlight .si { color: #3333bb; background-color: #fff0f0 } /* Literal.String.Interpol */ .highlight .sx { color: #22bb22; background-color: #f0fff0 } /* Literal.String.Other */ .highlight .sr { color: #008800; background-color: #fff0ff } /* Literal.String.Regex */ .highlight .s1 { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Single */ .highlight .ss { color: #aa6600; background-color: #fff0f0 } /* Literal.String.Symbol */ .highlight .bp { color: #003388 } /* Name.Builtin.Pseudo */ .highlight .fm { color: #0066bb; font-weight: bold } /* Name.Function.Magic */ .highlight .vc { color: #336699 } /* Name.Variable.Class */ .highlight .vg { color: #dd7700 } /* Name.Variable.Global */ .highlight .vi { color: #3333bb } /* Name.Variable.Instance */ .highlight .vm { color: #336699 } /* Name.Variable.Magic */ .highlight .il { color: #0000DD; font-weight: bold } /* Literal.Number.Integer.Long */ using Tango.Core.DI; using Tango.MachineStudio.DataCapture.ViewModels; using Tango.MachineStudio.DataCapture.Views; namespace Tango.MachineStudio.DataCapture { /// <summary> /// This class contains static references to all the view models in the /// application and provides an entry point for the bindings. /// </summary> public static class ViewModelLocator { /// <summary> /// Initializes a new instance of the ViewModelLocator class. /// </summary> static ViewModelLocator() { TangoIOC.Default.Register<MainViewVM>(); } public static MainViewVM MainViewVM { get { return TangoIOC.Default.GetInstance<MainViewVM>(); } } } }

generated by cgit v1.3.1 (git 2.54.0) at 2026-07-09 10:15:07 +0000

// Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
// This code is distributed under the GNU LGPL (for details please see \doc\license.txt)

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Windows;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media.TextFormatting;
using Tango.Scripting.Editors.Document;
using Tango.Scripting.Editors.Rendering;
using Tango.Scripting.Editors.Utils;

namespace Tango.Scripting.Editors.Editing
{
	static class CaretNavigationCommandHandler
	{
		/// <summary>
		/// Creates a new <see cref="TextAreaInputHandler"/> for the text area.
		/// </summary>
		public static TextAreaInputHandler Create(TextArea textArea)
		{
			TextAreaInputHandler handler = new TextAreaInputHandler(textArea);
			handler.CommandBindings.AddRange(CommandBindings);
			handler.InputBindings.AddRange(InputBindings);
			return handler;
		}
		
		static readonly List<CommandBinding> CommandBindings = new List<CommandBinding>();
		static readonly List<InputBinding> InputBindings = new List<InputBinding>();
		
		static void AddBinding(ICommand command, ModifierKeys modifiers, Key key, ExecutedRoutedEventHandler handler)
		{
			CommandBindings.Add(new CommandBinding(command, handler));
			InputBindings.Add(TextAreaDefaultInputHandler.CreateFrozenKeyBinding(command, modifiers, key));
		}
		
		static CaretNavigationCommandHandler()
		{
			const ModifierKeys None = ModifierKeys.None;
			const ModifierKeys Ctrl = ModifierKeys.Control;
			const ModifierKeys Shift = ModifierKeys.Shift;
			const ModifierKeys Alt = ModifierKeys.Alt;
			
			AddBinding(EditingCommands.MoveLeftByCharacter, None, Key.Left, OnMoveCaret(CaretMovementType.CharLeft));
			AddBinding(EditingCommands.SelectLeftByCharacter, Shift, Key.Left, OnMoveCaretExtendSelection(CaretMovementType.CharLeft));
			AddBinding(RectangleSelection.BoxSelectLeftByCharacter, Alt | Shift, Key.Left, OnMoveCaretBoxSelection(CaretMovementType.CharLeft));
			AddBinding(EditingCommands.MoveRightByCharacter, None, Key.Right, OnMoveCaret(CaretMovementType.CharRight));
			AddBinding(EditingCommands.SelectRightByCharacter, Shift, Key.Right, OnMoveCaretExtendSelection(CaretMovementType.CharRight));
			AddBinding(RectangleSelection.BoxSelectRightByCharacter, Alt | Shift, Key.Right, OnMoveCaretBoxSelection(CaretMovementType.CharRight));
			
			AddBinding(EditingCommands.MoveLeftByWord, Ctrl, Key.Left, OnMoveCaret(CaretMovementType.WordLeft));
			AddBinding(EditingCommands.SelectLeftByWord, Ctrl | Shift, Key.Left, OnMoveCaretExtendSelection(CaretMovementType.WordLeft));
			AddBinding(RectangleSelection.BoxSelectLeftByWord, Ctrl | Alt | Shift, Key.Left, OnMoveCaretBoxSelection(CaretMovementType.WordLeft));
			AddBinding(EditingCommands.MoveRightByWord, Ctrl, Key.Right, OnMoveCaret(CaretMovementType.WordRight));
			AddBinding(EditingCommands.SelectRightByWord, Ctrl | Shift, Key.Right, OnMoveCaretExtendSelection(CaretMovementType.WordRight));
			AddBinding(RectangleSelection.BoxSelectRightByWord, Ctrl | Alt | Shift, Key.Right, OnMoveCaretBoxSelection(CaretMovementType.WordRight));
			
			AddBinding(EditingCommands.MoveUpByLine, None, Key.Up, OnMoveCaret(CaretMovementType.LineUp));
			AddBinding(EditingCommands.SelectUpByLine, Shift, Key.Up, OnMoveCaretExtendSelection(CaretMovementType.LineUp));
			AddBinding(RectangleSelection.BoxSelectUpByLine, Alt | Shift, Key.Up, OnMoveCaretBoxSelection(CaretMovementType.LineUp));
			AddBinding(EditingCommands.MoveDownByLine, None, Key.Down, OnMoveCaret(CaretMovementType.LineDown));
			AddBinding(EditingCommands.SelectDownByLine, Shift, Key.Down, OnMoveCaretExtendSelection(CaretMovementType.LineDown));
			AddBinding(RectangleSelection.BoxSelectDownByLine, Alt | Shift, Key.Down, OnMoveCaretBoxSelection(CaretMovementType.LineDown));
			
			AddBinding(EditingCommands.MoveDownByPage, None, Key.PageDown, OnMoveCaret(CaretMovementType.PageDown));
			AddBinding(EditingCommands.SelectDownByPage, Shift, Key.PageDown, OnMoveCaretExtendSelection(CaretMovementType.PageDown));
			AddBinding(EditingCommands.MoveUpByPage, None, Key.PageUp, OnMoveCaret(CaretMovementType.PageUp));
			AddBinding(EditingCommands.SelectUpByPage, Shift, Key.PageUp, OnMoveCaretExtendSelection(CaretMovementType.PageUp));
			
			AddBinding(EditingCommands.MoveToLineStart, None, Key.Home, OnMoveCaret(CaretMovementType.LineStart));
			AddBinding(EditingCommands.SelectToLineStart, Shift, Key.Home, OnMoveCaretExtendSelection(CaretMovementType.LineStart));
			AddBinding(RectangleSelection.BoxSelectToLineStart, Alt | Shift, Key.Home, OnMoveCaretBoxSelection(CaretMovementType.LineStart));
			AddBinding(EditingCommands.MoveToLineEnd, None, Key.End, OnMoveCaret(CaretMovementType.LineEnd));
			AddBinding(EditingCommands.SelectToLineEnd, Shift, Key.End, OnMoveCaretExtendSelection(CaretMovementType.LineEnd));
			AddBinding(RectangleSelection.BoxSelectToLineEnd, Alt | Shift, Key.End, OnMoveCaretBoxSelection(CaretMovementType.LineEnd));
			
			AddBinding(EditingCommands.MoveToDocumentStart, Ctrl, Key.Home, OnMoveCaret(CaretMovementType.DocumentStart));
			AddBinding(EditingCommands.SelectToDocumentStart, Ctrl | Shift, Key.Home, OnMoveCaretExtendSelection(CaretMovementType.DocumentStart));
			AddBinding(EditingCommands.MoveToDocumentEnd, Ctrl, Key.End, OnMoveCaret(CaretMovementType.DocumentEnd));
			AddBinding(EditingCommands.SelectToDocumentEnd, Ctrl | Shift, Key.End, OnMoveCaretExtendSelection(CaretMovementType.DocumentEnd));
			
			CommandBindings.Add(new CommandBinding(ApplicationCommands.SelectAll, OnSelectAll));
			
			TextAreaDefaultInputHandler.WorkaroundWPFMemoryLeak(InputBindings);
		}
		
		static void OnSelectAll(object target, ExecutedRoutedEventArgs args)
		{
			TextArea textArea = GetTextArea(target);
			if (textArea != null && textArea.Document != null) {
				args.Handled = true;
				textArea.Caret.Offset = textArea.Document.TextLength;
				textArea.Selection = SimpleSelection.Create(textArea, 0, textArea.Document.TextLength);
			}
		}
		
		static TextArea GetTextArea(object target)
		{
			return target as TextArea;
		}
		
		enum CaretMovementType
		{
			CharLeft,
			CharRight,
			WordLeft,
			WordRight,
			LineUp,
			LineDown,
			PageUp,
			PageDown,
			LineStart,
			LineEnd,
			DocumentStart,
			DocumentEnd
		}
		
		static ExecutedRoutedEventHandler OnMoveCaret(CaretMovementType direction)
		{
			return (target, args) => {
				TextArea textArea = GetTextArea(target);
				if (textArea != null && textArea.Document != null) {
					args.Handled = true;
					textArea.ClearSelection();
					MoveCaret(textArea, direction);
					textArea.Caret.BringCaretToView();
				}
			};
		}
		
		static ExecutedRoutedEventHandler OnMoveCaretExtendSelection(CaretMovementType direction)
		{
			return (target, args) => {
				TextArea textArea = GetTextArea(target);
				if (textArea != null && textArea.Document != null) {
					args.Handled = true;
					TextViewPosition oldPosition = textArea.Caret.Position;
					MoveCaret(textArea, direction);
					textArea.Selection = textArea.Selection.StartSelectionOrSetEndpoint(oldPosition, textArea.Caret.Position);
					if (!textArea.Document.IsInUpdate) // if we're inside a larger update (e.g. called by EditingCommandHandler.OnDelete()), avoid calculating the caret rectangle now
						textArea.Caret.BringCaretToView();
				}
			};
		}
		
		static ExecutedRoutedEventHandler OnMoveCaretBoxSelection(CaretMovementType direction)
		{
			return (target, args) => {
				TextArea textArea = GetTextArea(target);
				if (textArea != null && textArea.Document != null) {
					args.Handled = true;
					// First, convert the selection into a rectangle selection
					// (this is required so that virtual space gets enabled for the caret movement)
					if (textArea.Options.EnableRectangularSelection && !(textArea.Selection is RectangleSelection)) {
						if (textArea.Selection.IsEmpty) {
							textArea.Selection = new RectangleSelection(textArea, textArea.Caret.Position, textArea.Caret.Position);
						} else {
							// Convert normal selection to rectangle selection
							textArea.Selection = new RectangleSelection(textArea, textArea.Selection.StartPosition, textArea.Caret.Position);
						}
					}
					// Now move the caret and extend the selection
					TextViewPosition oldPosition = textArea.Caret.Position;
					MoveCaret(textArea, direction);
					textArea.Selection = textArea.Selection.StartSelectionOrSetEndpoint(oldPosition, textArea.Caret.Position);
					textArea.Caret.BringCaretToView();
				}
			};
		}
		
		#region Caret movement
		static void MoveCaret(TextArea textArea, CaretMovementType direction)
		{
			DocumentLine caretLine = textArea.Document.GetLineByNumber(textArea.Caret.Line);
			VisualLine visualLine = textArea.TextView.GetOrConstructVisualLine(caretLine);
			TextViewPosition caretPosition = textArea.Caret.Position;
			TextLine textLine = visualLine.GetTextLine(caretPosition.VisualColumn);
			switch (direction) {
				case CaretMovementType.CharLeft:
					MoveCaretLeft(textArea, caretPosition, visualLine, CaretPositioningMode.Normal);
					break;
				case CaretMovementType.CharRight:
					MoveCaretRight(textArea, caretPosition, visualLine, CaretPositioningMode.Normal);
					break;
				case CaretMovementType.WordLeft:
					MoveCaretLeft(textArea, caretPosition, visualLine, CaretPositioningMode.WordStart);
					break;
				case CaretMovementType.WordRight:
					MoveCaretRight(textArea, caretPosition, visualLine, CaretPositioningMode.WordStart);
					break;
				case CaretMovementType.LineUp:
				case CaretMovementType.LineDown:
				case CaretMovementType.PageUp:
				case CaretMovementType.PageDown:
					MoveCaretUpDown(textArea, direction, visualLine, textLine, caretPosition.VisualColumn);
					break;
				case CaretMovementType.DocumentStart:
					SetCaretPosition(textArea, 0, 0);
					break;
				case CaretMovementType.DocumentEnd:
					SetCaretPosition(textArea, -1, textArea.Document.TextLength);
					break;
				case CaretMovementType.LineStart:
					MoveCaretToStartOfLine(textArea, visualLine);
					break;
				case CaretMovementType.LineEnd:
					MoveCaretToEndOfLine(textArea, visualLine);
					break;
				default:
					throw new NotSupportedException(direction.ToString());
			}
		}
		#endregion
		
		#region Home/End
		static void MoveCaretToStartOfLine(TextArea textArea, VisualLine visualLine)
		{
			int newVC = visualLine.GetNextCaretPosition(-1, LogicalDirection.Forward, CaretPositioningMode.WordStart, textArea.Selection.EnableVirtualSpace);
			if (newVC < 0)
				throw ThrowUtil.NoValidCaretPosition();
			// when the caret is already at the start of the text, jump to start before whitespace
			if (newVC == textArea.Caret.VisualColumn)
				newVC = 0;
			int offset = visualLine.FirstDocumentLine.Offset + visualLine.GetRelativeOffset(newVC);
			SetCaretPosition(textArea, newVC, offset);
		}
		
		static void MoveCaretToEndOfLine(TextArea textArea, VisualLine visualLine)
		{
			int newVC = visualLine.VisualLength;
			int offset = visualLine.FirstDocumentLine.Offset + visualLine.GetRelativeOffset(newVC);
			SetCaretPosition(textArea, newVC, offset);
		}
		#endregion
		
		#region By-character / By-word movement
		static void MoveCaretRight(TextArea textArea, TextViewPosition caretPosition, VisualLine visualLine, CaretPositioningMode mode)
		{
			int pos = visualLine.GetNextCaretPosition(caretPosition.VisualColumn, LogicalDirection.Forward, mode, textArea.Selection.EnableVirtualSpace);
			if (pos >= 0) {
				SetCaretPosition(textArea, pos, visualLine.GetRelativeOffset(pos) + visualLine.FirstDocumentLine.Offset);
			} else {
				// move to start of next line
				DocumentLine nextDocumentLine = visualLine.LastDocumentLine.NextLine;
				if (nextDocumentLine != null) {
					VisualLine nextLine = textArea.TextView.GetOrConstructVisualLine(nextDocumentLine);
					pos = nextLine.GetNextCaretPosition(-1, LogicalDirection.Forward, mode, textArea.Selection.EnableVirtualSpace);
					if (pos < 0)
						throw ThrowUtil.NoValidCaretPosition();
					SetCaretPosition(textArea, pos, nextLine.GetRelativeOffset(pos) + nextLine.FirstDocumentLine.Offset);
				} else {
					// at end of document
					Debug.Assert(visualLine.LastDocumentLine.Offset + visualLine.LastDocumentLine.TotalLength == textArea.Document.TextLength);
					SetCaretPosition(textArea, -1, textArea.Document.TextLength);
				}
			}
		}
		
		static void MoveCaretLeft(TextArea textArea, TextViewPosition caretPosition, VisualLine visualLine, CaretPositioningMode mode)
		{
			int pos = visualLine.GetNextCaretPosition(caretPosition.VisualColumn, LogicalDirection.Backward, mode, textArea.Selection.EnableVirtualSpace);
			if (pos >= 0) {
				SetCaretPosition(textArea, pos, visualLine.GetRelativeOffset(pos) + visualLine.FirstDocumentLine.Offset);
			} else {
				// move to end of previous line
				DocumentLine previousDocumentLine = visualLine.FirstDocumentLine.PreviousLine;
				if (previousDocumentLine != null) {
					VisualLine previousLine = textArea.TextView.GetOrConstructVisualLine(previousDocumentLine);
					pos = previousLine.GetNextCaretPosition(previousLine.VisualLength + 1, LogicalDirection.Backward, mode, textArea.Selection.EnableVirtualSpace);
					if (pos < 0)
						throw ThrowUtil.NoValidCaretPosition();
					SetCaretPosition(textArea, pos, previousLine.GetRelativeOffset(pos) + previousLine.FirstDocumentLine.Offset);
				} else {
					// at start of document
					Debug.Assert(visualLine.FirstDocumentLine.Offset == 0);
					SetCaretPosition(textArea, 0, 0);
				}
			}
		}
		#endregion

		#region Line+Page up/down
		static void MoveCaretUpDown(TextArea textArea, CaretMovementType direction, VisualLine visualLine, TextLine textLine, int caretVisualColumn)
		{
			// moving up/down happens using the desired visual X position
			double xPos = textArea.Caret.DesiredXPos;
			if (double.IsNaN(xPos))
				xPos = visualLine.GetTextLineVisualXPosition(textLine, caretVisualColumn);
			// now find the TextLine+VisualLine where the caret will end up in
			VisualLine targetVisualLine = visualLine;
			TextLine targetLine;
			int textLineIndex = visualLine.TextLines.IndexOf(textLine);
			switch (direction) {
				case CaretMovementType.LineUp:
					{
						// Move up: move to the previous TextLine in the same visual line
						// or move to the last TextLine of the previous visual line
						int prevLineNumber = visualLine.FirstDocumentLine.LineNumber - 1;
						if (textLineIndex > 0) {
							targetLine = visualLine.TextLines[textLineIndex - 1];
						} else if (prevLineNumber >= 1) {
							DocumentLine prevLine = textArea.Document.GetLineByNumber(prevLineNumber);
							targetVisualLine = textArea.TextView.GetOrConstructVisualLine(prevLine);
							targetLine = targetVisualLine.TextLines[targetVisualLine.TextLines.Count - 1];
						} else {
							targetLine = null;
						}
						break;
					}
				case CaretMovementType.LineDown:
					{
						// Move down: move to the next TextLine in the same visual line
						// or move to the first TextLine of the next visual line
						int nextLineNumber = visualLine.LastDocumentLine.LineNumber + 1;
						if (textLineIndex < visualLine.TextLines.Count - 1) {
							targetLine = visualLine.TextLines[textLineIndex + 1];
						} else if (nextLineNumber <= textArea.Document.LineCount) {
							DocumentLine nextLine = textArea.Document.GetLineByNumber(nextLineNumber);
							targetVisualLine = textArea.TextView.GetOrConstructVisualLine(nextLine);
							targetLine = targetVisualLine.TextLines[0];
						} else {
							targetLine = null;
						}
						break;
					}
				case CaretMovementType.PageUp:
				case CaretMovementType.PageDown:
					{
						// Page up/down: find the target line using its visual position
						double yPos = visualLine.GetTextLineVisualYPosition(textLine, VisualYPosition.LineMiddle);
						if (direction == CaretMovementType.PageUp)
							yPos -= textArea.TextView.RenderSize.Height;
						else
							yPos += textArea.TextView.RenderSize.Height;
						DocumentLine newLine = textArea.TextView.GetDocumentLineByVisualTop(yPos);
						targetVisualLine = textArea.TextView.GetOrConstructVisualLine(newLine);
						targetLine = targetVisualLine.GetTextLineByVisualYPosition(yPos);
						break;
					}
				default:
					throw new NotSupportedException(direction.ToString());
			}
			if (targetLine != null) {
				double yPos = targetVisualLine.GetTextLineVisualYPosition(targetLine, VisualYPosition.LineMiddle);
				int newVisualColumn = targetVisualLine.GetVisualColumn(new Point(xPos, yPos), textArea.Selection.EnableVirtualSpace);
				SetCaretPosition(textArea, targetVisualLine, targetLine, newVisualColumn, false);
				textArea.Caret.DesiredXPos = xPos;
			}
		}
		#endregion
		
		#region SetCaretPosition
		static void SetCaretPosition(TextArea textArea, VisualLine targetVisualLine, TextLine targetLine,
		                             int newVisualColumn, bool allowWrapToNextLine)
		{
			int targetLineStartCol = targetVisualLine.GetTextLineVisualStartColumn(targetLine);
			if (!allowWrapToNextLine && newVisualColumn >= targetLineStartCol + targetLine.Length) {
				if (newVisualColumn <= targetVisualLine.VisualLength)
					newVisualColumn = targetLineStartCol + targetLine.Length - 1;
			}
			int newOffset = targetVisualLine.GetRelativeOffset(newVisualColumn) + targetVisualLine.FirstDocumentLine.Offset;
			SetCaretPosition(textArea, newVisualColumn, newOffset);
		}
		
		static void SetCaretPosition(TextArea textArea, int newVisualColumn, int newOffset)
		{
			textArea.Caret.Position = new TextViewPosition(textArea.Document.GetLocation(newOffset), newVisualColumn);
			textArea.Caret.DesiredXPos = double.NaN;
		}
		#endregion
	}
}