* TextBoxBase.cs: Default selection length is -1, need to do

[mono-project.git] / mcs / class / Managed.Windows.Forms / System.Windows.Forms / TextBoxBase.cs

// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
// Copyright (c) 2004-2006 Novell, Inc. (http://www.novell.com)
//
// Authors:
//      Peter Bartok    pbartok@novell.com
//
//

// NOT COMPLETE
#undef Debug
#undef DebugClick

using System.ComponentModel;
using System.ComponentModel.Design;
using System.Drawing;
using System.Drawing.Text;
using System.Text;
using System.Runtime.InteropServices;
using System.Collections;

namespace System.Windows.Forms {
        [DefaultEvent("TextChanged")]
        [Designer("System.Windows.Forms.Design.TextBoxBaseDesigner, " + Consts.AssemblySystem_Design)]
        public abstract class TextBoxBase : Control {
                #region Local Variables
                internal HorizontalAlignment    alignment;
                internal bool                   accepts_tab;
                internal bool                   accepts_return;
                internal bool                   auto_size;
                internal bool                   backcolor_set;
                internal CharacterCasing        character_casing;
                internal bool                   undo;
                internal bool                   hide_selection;
                internal int                    max_length;
                internal bool                   modified;
                internal bool                   multiline;
                internal char                   password_char;
                internal bool                   read_only;
                internal bool                   word_wrap;
                internal Document               document;
                internal LineTag                caret_tag;              // tag our cursor is in
                internal int                    caret_pos;              // position on the line our cursor is in (can be 0 = beginning of line)
                internal ImplicitHScrollBar     hscroll;
                internal ImplicitVScrollBar     vscroll;
                internal RichTextBoxScrollBars  scrollbars;
                internal Timer                  scroll_timer;
                internal bool                   richtext;
                internal bool                   show_selection;         // set to true to always show selection, even if no focus is set
                internal int                    selection_length = -1;  // set to the user-specified selection length, or -1 if none
                internal int                    requested_height;
                internal int                    canvas_width;
                internal int                    canvas_height;
                static internal int             track_width = 2;        //
                static internal int             track_border = 5;       //
                internal DateTime               click_last;
                internal CaretSelection         click_mode;
                internal Bitmap                 bmp;
                #if Debug
                internal static bool    draw_lines = false;
                #endif

                #endregion      // Local Variables

                #region Internal Constructor
                // Constructor will go when complete, only for testing - pdb
                internal TextBoxBase() {
                        alignment = HorizontalAlignment.Left;
                        accepts_return = false;
                        accepts_tab = false;
                        auto_size = true;
                        border_style = BorderStyle.Fixed3D;
                        character_casing = CharacterCasing.Normal;
                        undo = false;
                        hide_selection = true;
                        max_length = 32767;
                        modified = false;
                        multiline = false;
                        password_char = '\0';
                        read_only = false;
                        word_wrap = true;
                        richtext = false;
                        show_selection = false;
                        document = new Document(this);
                        document.WidthChanged += new EventHandler(document_WidthChanged);
                        document.HeightChanged += new EventHandler(document_HeightChanged);
                        //document.CaretMoved += new EventHandler(CaretMoved);
                        document.Wrap = false;
                        requested_height = -1;
                        click_last = DateTime.Now;
                        click_mode = CaretSelection.Position;
                        bmp = new Bitmap(1, 1, System.Drawing.Imaging.PixelFormat.Format32bppArgb);

                        MouseDown += new MouseEventHandler(TextBoxBase_MouseDown);
                        MouseUp += new MouseEventHandler(TextBoxBase_MouseUp);
                        MouseMove += new MouseEventHandler(TextBoxBase_MouseMove);
                        SizeChanged += new EventHandler(TextBoxBase_SizeChanged);
                        FontChanged += new EventHandler(TextBoxBase_FontOrColorChanged);
                        ForeColorChanged += new EventHandler(TextBoxBase_FontOrColorChanged);
                        MouseWheel += new MouseEventHandler(TextBoxBase_MouseWheel);
                        
                        scrollbars = RichTextBoxScrollBars.None;

                        hscroll = new ImplicitHScrollBar();
                        hscroll.ValueChanged += new EventHandler(hscroll_ValueChanged);
                        hscroll.control_style &= ~ControlStyles.Selectable;
                        hscroll.Enabled = false;
                        hscroll.Visible = false;
                        hscroll.Maximum = Int32.MaxValue;

                        vscroll = new ImplicitVScrollBar();
                        vscroll.ValueChanged += new EventHandler(vscroll_ValueChanged);
                        vscroll.control_style &= ~ControlStyles.Selectable;
                        vscroll.Enabled = false;
                        vscroll.Visible = false;
                        vscroll.Maximum = Int32.MaxValue;

                        SuspendLayout ();
                        this.Controls.AddImplicit (hscroll);
                        this.Controls.AddImplicit (vscroll);
                        ResumeLayout ();
                        
                        SetStyle(ControlStyles.UserPaint | ControlStyles.StandardClick, false);
#if NET_2_0
                        SetStyle(ControlStyles.UseTextForAccessibility, false);
#endif

                        canvas_width = ClientSize.Width;
                        canvas_height = ClientSize.Height;
                        document.ViewPortWidth = canvas_width;
                        document.ViewPortHeight = canvas_height;

                        Cursor = Cursors.IBeam;

                        CalculateScrollBars();
                }
                #endregion      // Internal Constructor

                #region Private and Internal Methods
                internal string CaseAdjust(string s) {
                        if (character_casing == CharacterCasing.Normal) {
                                return s;
                        }
                        if (character_casing == CharacterCasing.Lower) {
                                return s.ToLower();
                        } else {
                                return s.ToUpper();
                        }
                }

                internal override void HandleClick(int clicks, MouseEventArgs me) {
                        // MS seems to fire the click event in spite of the styles they set
                        control_style |= ControlStyles.StandardClick | ControlStyles.StandardDoubleClick;
                        base.HandleClick (clicks, me);
                        control_style ^= ControlStyles.StandardClick | ControlStyles.StandardDoubleClick;
                }

                #endregion      // Private and Internal Methods

                #region Public Instance Properties
                [DefaultValue(false)]
                [MWFCategory("Behavior")]
                public bool AcceptsTab {
                        get {
                                return accepts_tab;
                        }

                        set {
                                if (value != accepts_tab) {
                                        accepts_tab = value;
                                        OnAcceptsTabChanged(EventArgs.Empty);
                                }
                        }
                }

                [DefaultValue(true)]
                [Localizable(true)]
                [RefreshProperties(RefreshProperties.Repaint)]
                [MWFCategory("Behavior")]
                public virtual bool AutoSize {
                        get {
                                return auto_size;
                        }

                        set {
                                if (value != auto_size) {
                                        auto_size = value;
                                        if (auto_size) {
                                                if (PreferredHeight != ClientSize.Height) {
                                                        ClientSize = new Size(ClientSize.Width, PreferredHeight);
                                                }
                                        }
                                        OnAutoSizeChanged(EventArgs.Empty);
                                }
                        }
                }

                [DispId(-501)]
                public override System.Drawing.Color BackColor {
                        get {
                                return base.BackColor;
                        }
                        set {
                                if (value != ThemeEngine.Current.ColorWindow) {
                                        backcolor_set = true;
                                } else {
                                        backcolor_set = false;
                                }
                                base.BackColor = value;
                        }
                }

                [Browsable(false)]
                [EditorBrowsable(EditorBrowsableState.Never)]
                public override System.Drawing.Image BackgroundImage {
                        get {
                                return base.BackgroundImage;
                        }
                        set {
                                base.BackgroundImage = value;
                        }
                }

                [DefaultValue(BorderStyle.Fixed3D)]
                [DispId(-504)]
                [MWFCategory("Appearance")]
                public BorderStyle BorderStyle {
                        get { return InternalBorderStyle; }
                        set { 
                                InternalBorderStyle = value; 
                                OnBorderStyleChanged(EventArgs.Empty);
                        }
                }

                [Browsable(false)]
                [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
                public bool CanUndo {
                        get {
                                return document.undo.UndoLevels != 0;
                        }
                }

                [DispId(-513)]
                public override System.Drawing.Color ForeColor {
                        get {
                                return base.ForeColor;
                        }
                        set {
                                base.ForeColor = value;
                        }
                }

                [DefaultValue(true)]
                [MWFCategory("Behavior")]
                public bool HideSelection {
                        get {
                                return hide_selection;
                        }

                        set {
                                if (value != hide_selection) {
                                        hide_selection = value;
                                        OnHideSelectionChanged(EventArgs.Empty);
                                }
                                if (hide_selection) {
                                        document.selection_visible = false;
                                } else {
                                        document.selection_visible = true;
                                }
                                document.InvalidateSelectionArea();

                        }
                }

                [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
                [Editor("System.Windows.Forms.Design.StringArrayEditor, " + Consts.AssemblySystem_Design, typeof(System.Drawing.Design.UITypeEditor))]
                [Localizable(true)]
                [MWFCategory("Appearance")]
                public string[] Lines {
                        get {
                                int count;
                                ArrayList lines;

                                count = document.Lines;

                                // Handle empty document
                                if ((count == 1) && (document.GetLine (1).text.Length == 0)) {
                                        return new string [0];
                                }

                                lines = new ArrayList ();

                                int i = 1;
                                while (i <= count) {
                                        Line line;
                                        StringBuilder lt = new StringBuilder ();

                                        do {
                                                line = document.GetLine (i++);
                                                lt.Append (line.text.ToString ());
                                        } while (line.soft_break && i < count);

                                        lines.Add (lt.ToString ());     
                                }

                                return (string []) lines.ToArray (typeof (string));
                        }

                        set {
                                int     i;
                                int     l;
                                Brush   brush;

                                document.Empty();

                                l = value.Length;
                                brush = ThemeEngine.Current.ResPool.GetSolidBrush(this.ForeColor);

                                document.NoRecalc = true;
                                for (i = 0; i < l; i++) {

                                        // Don't add the last line if it is just an empty line feed
                                        // the line feed is reflected in the previous line's soft_break = false
                                        if (i == l - 1 && value [i].Length == 0)
                                                break;

                                        bool carriage_return = false;
                                        if (value [i].EndsWith ("\r")) {
                                                value [i] = value [i].Substring (0, value [i].Length - 1);
                                                carriage_return = true;
                                        }

                                        document.Add(i+1, CaseAdjust(value[i]), alignment, Font, brush);
                                        if (carriage_return) {
                                                Line line = document.GetLine (i + 1);
                                                line.carriage_return = true;
                                        }
                                }

                                document.NoRecalc = false;

                                // CalculateDocument();
                                OnTextChanged(EventArgs.Empty);
                        }
                }

                [DefaultValue(32767)]
                [Localizable(true)]
                [MWFCategory("Behavior")]
                public virtual int MaxLength {
                        get {
                                if (max_length == 2147483646) { // We don't distinguish between single and multi-line limits
                                        return 0;
                                }
                                return max_length;
                        }

                        set {
                                if (value != max_length) {
                                        max_length = value;
                                }
                        }
                }

                [Browsable(false)]
                [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
                public bool Modified {
                        get {
                                return modified;
                        }

                        set {
                                if (value != modified) {
                                        modified = value;
                                        OnModifiedChanged(EventArgs.Empty);
                                }
                        }
                }

                [DefaultValue(false)]
                [Localizable(true)]
                [RefreshProperties(RefreshProperties.All)]
                [MWFCategory("Behavior")]
                public virtual bool Multiline {
                        get {
                                return multiline;
                        }

                        set {
                                if (value != multiline) {
                                        multiline = value;
                                        // Make sure we update our size; the user may have already set the size before going to multiline
                                        if (multiline && requested_height != -1) {
                                                Height = requested_height;
                                                requested_height = -1;
                                        }

                                        if (parent != null)
                                                parent.PerformLayout ();

                                        OnMultilineChanged(EventArgs.Empty);
                                }

                                document.multiline = multiline;

                                if (multiline) {
                                        document.Wrap = word_wrap;
                                        document.PasswordChar = "";

                                } else {
                                        document.Wrap = false;
                                        if (this.password_char != '\0') {
                                                document.PasswordChar = password_char.ToString();
                                        } else {
                                                document.PasswordChar = "";
                                        }
                                }

                                CalculateDocument ();
                        }
                }

                [Browsable(false)]
                [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
                [EditorBrowsable(EditorBrowsableState.Advanced)]
                public int PreferredHeight {
                        get {
                                return this.Font.Height + 7;    // FIXME - consider border style as well
                        }
                }

                [DefaultValue(false)]
                [MWFCategory("Behavior")]
                public bool ReadOnly {
                        get {
                                return read_only;
                        }

                        set {
                                if (value != read_only) {
                                        read_only = value;
                                        OnReadOnlyChanged(EventArgs.Empty);
                                }
                        }
                }

                [Browsable(false)]
                [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
                public virtual string SelectedText {
                        get {
                                return document.GetSelection();
                        }

                        set {
                                document.ReplaceSelection(CaseAdjust(value), false);
                                        
                                ScrollToCaret();
                                OnTextChanged(EventArgs.Empty);
                        }
                }

                [Browsable(false)]
                [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
                public virtual int SelectionLength {
                        get {
                                int res = document.SelectionLength ();
                                if (res == 0)
                                        res = -1;
                                return res;
                        }

                        set {
                                if (value < 0) {
                                        throw new ArgumentException(String.Format("{0} is not a valid value", value), "value");
                                }

                                if (value != 0) {
                                        int     start;
                                        Line    line;
                                        LineTag tag;
                                        int     pos;

                                        selection_length = value;

                                        start = document.LineTagToCharIndex(document.selection_start.line, document.selection_start.pos);

                                        document.CharIndexToLineTag(start + value, out line, out tag, out pos);
                                        document.SetSelectionEnd(line, pos);
                                        document.PositionCaret(line, pos);
                                } else {
                                        selection_length = -1;

                                        document.SetSelectionEnd(document.selection_start.line, document.selection_start.pos);
                                        document.PositionCaret(document.selection_start.line, document.selection_start.pos);
                                }
                        }
                }

                [Browsable(false)]
                [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
                public int SelectionStart {
                        get {
                                int index;

                                index = document.LineTagToCharIndex(document.selection_start.line, document.selection_start.pos);

                                return index;
                        }

                        set {
                                document.SetSelectionStart(value);
                                if (selection_length > -1 ) {
                                        document.SetSelectionEnd(value + selection_length);
                                } else {
                                        document.SetSelectionEnd(value);
                                }
                                document.PositionCaret(document.selection_start.line, document.selection_start.pos);
                                ScrollToCaret();
                        }
                }

                [Localizable(true)]
                public override string Text {
                        get {
                                if (document == null || document.Root == null || document.Root.text == null) {
                                        return string.Empty;
                                }

                                if (!multiline) {
                                        return document.Root.text.ToString();
                                } else {
                                        StringBuilder   sb;
                                        int             i;

                                        sb = new StringBuilder();

                                        Line line = null;
                                        for (i = 1; i < document.Lines; i++) {
                                                if (line != null && !line.soft_break)
                                                        sb.Append (Environment.NewLine);
                                                line = document.GetLine (i);
                                                sb.Append(line.text.ToString());
                                                if (line.carriage_return)
                                                        sb.Append ("\r");
                                        }
                                        sb.Append(document.GetLine(document.Lines).text.ToString());
                                        return sb.ToString();
                                }
                        }

                        set {
                                if (value == Text)
                                        return;

                                if ((value != null) && (value != "")) {
                                        Line    line;

                                        if (multiline) {
                                                string[]        lines;

                                                lines = value.Split(new char[] {'\n'});

                                                this.Lines = lines;
                                                        
                                                document.PositionCaret (document.GetLine (1), 0);
                                                document.SetSelectionToCaret (true);

                                                ScrollToCaret ();
                                        } else {
                                                document.Clear();
                                                document.Add(1, CaseAdjust(value), alignment, Font, ThemeEngine.Current.ResPool.GetSolidBrush(ForeColor));
                                                CalculateDocument();

                                                document.PositionCaret (document.GetLine (1), 0);
                                                document.SetSelectionToCaret (true);

                                                ScrollToCaret ();
                                        }
                                } else {
                                        document.Empty();
                                        CalculateDocument();
                                }

                                OnTextChanged(EventArgs.Empty);
                        }
                }

                [Browsable(false)]
                public virtual int TextLength {
                        get {
                                if (document == null || document.Root == null || document.Root.text == null) {
                                        return 0;
                                }

                                if (!multiline) {
                                        return document.Root.text.Length;
                                } else {
                                        int     total;
                                        int     i;

                                        total = 0;
                                        for (i = 1; i < document.Lines; i++) {
                                                total += document.GetLine(i).text.Length + Environment.NewLine.Length;
                                        }
                                        total += document.GetLine(i).text.Length;

                                        return total;
                                }
                        }
                }

                [DefaultValue(true)]
                [Localizable(true)]
                [MWFCategory("Behavior")]
                public bool WordWrap {
                        get {
                                return word_wrap;
                        }

                        set {
                                if (value != word_wrap) {
                                        if (multiline) {
                                                word_wrap = value;
                                                document.Wrap = value;
                                        }
                                }
                        }
                }
                #endregion      // Public Instance Properties

                #region Protected Instance Properties
                protected override CreateParams CreateParams {
                        get {
                                return base.CreateParams;
                        }
                }

                protected override System.Drawing.Size DefaultSize {
                        get {
                                return new Size(100, 20);
                        }
                }
                #endregion      // Protected Instance Properties

                #region Public Instance Methods
                public void AppendText(string text) {
                        if (multiline) {

                                document.MoveCaret(CaretDirection.CtrlEnd);                             
                                document.Insert (document.caret.line, document.caret.tag, document.caret.pos, false, text);
                                CalculateDocument();
                        } else {
                                document.MoveCaret(CaretDirection.CtrlEnd);
                                document.InsertStringAtCaret(text, true);

                                Invalidate();
                        }

                        document.MoveCaret(CaretDirection.CtrlEnd);
                        document.SetSelectionToCaret (true);

                        OnTextChanged(EventArgs.Empty);
                }

                public void Clear() {
                        Text = null;
                }

                public void ClearUndo() {
                        document.undo.Clear();
                }

                public void Copy() {
                        DataObject      o;

                        o = new DataObject(DataFormats.Text, SelectedText);
                        if (this is RichTextBox) {
                                o.SetData(DataFormats.Rtf, ((RichTextBox)this).SelectedRtf);
                        }
                        Clipboard.SetDataObject(o);
                }

                public void Cut() {
                        DataObject      o;

                        o = new DataObject(DataFormats.Text, SelectedText);
                        if (this is RichTextBox) {
                                o.SetData(DataFormats.Rtf, ((RichTextBox)this).SelectedRtf);
                        }
                        Clipboard.SetDataObject(o);
                        document.ReplaceSelection("", false);
                }

                public void Paste() {
                        Paste(Clipboard.GetDataObject(), null, false);
                }

                public void ScrollToCaret() {
                        if (IsHandleCreated) {
                                CaretMoved(this, EventArgs.Empty);
                        }
                }

                public void Select(int start, int length) {
                        SelectionStart = start;
                        SelectionLength = length;
                }


                public void SelectAll() {
                        Line    last;

                        last = document.GetLine(document.Lines);
                        document.SetSelectionStart(document.GetLine(1), 0);
                        document.SetSelectionEnd(last, last.text.Length);
                        selection_length = -1;
                }

                public override string ToString() {
                        return String.Concat (base.ToString (), ", Text: ", Text);
                }

                public void Undo() {
                        document.undo.Undo();
                }
                #endregion      // Public Instance Methods

                #region Protected Instance Methods
                protected override void CreateHandle() {
                        base.CreateHandle ();
                        document.AlignCaret();
                        ScrollToCaret();
                }

                protected override bool IsInputKey(Keys keyData) {
                        if ((keyData & Keys.Alt) != 0) {
                                return base.IsInputKey(keyData);
                        }

                        switch (keyData & Keys.KeyCode) {
                                case Keys.Enter: {
                                        if (multiline && accepts_return) {
                                                return true;
                                        }
                                        return false;
                                }

                                case Keys.Tab: {
                                        if (accepts_tab && multiline) {
                                                if ((keyData & Keys.Control) == 0) {
                                                        return true;
                                                }
                                        }
                                        return false;
                                }

                                case Keys.Left:
                                case Keys.Right:
                                case Keys.Up:
                                case Keys.Down:
                                case Keys.PageUp:
                                case Keys.PageDown:
                                case Keys.Home:
                                case Keys.End: {
                                        return true;
                                }
                        }
                        return false;
                }


                protected virtual void OnAcceptsTabChanged(EventArgs e) {
                        EventHandler eh = (EventHandler)(Events [AcceptsTabChangedEvent]);
                        if (eh != null)
                                eh (this, e);
                }

                protected virtual void OnAutoSizeChanged(EventArgs e) {
                        EventHandler eh = (EventHandler)(Events [AutoSizeChangedEvent]);
                        if (eh != null)
                                eh (this, e);
                }

                protected virtual void OnBorderStyleChanged(EventArgs e) {
                        EventHandler eh = (EventHandler)(Events [BorderStyleChangedEvent]);
                        if (eh != null)
                                eh (this, e);
                }

                protected override void OnFontChanged(EventArgs e) {
                        base.OnFontChanged (e);

                        if (auto_size && !multiline) {
                                if (PreferredHeight != ClientSize.Height) {
                                        Height = PreferredHeight;
                                }
                        }
                }

                protected override void OnHandleCreated(EventArgs e) {
                        base.OnHandleCreated (e);
                }

                protected override void OnHandleDestroyed(EventArgs e) {
                        base.OnHandleDestroyed (e);
                }

                protected virtual void OnHideSelectionChanged(EventArgs e) {
                        EventHandler eh = (EventHandler)(Events [HideSelectionChangedEvent]);
                        if (eh != null)
                                eh (this, e);
                }

                protected virtual void OnModifiedChanged(EventArgs e) {
                        EventHandler eh = (EventHandler)(Events [ModifiedChangedEvent]);
                        if (eh != null)
                                eh (this, e);
                }

                protected virtual void OnMultilineChanged(EventArgs e) {
                        EventHandler eh = (EventHandler)(Events [MultilineChangedEvent]);
                        if (eh != null)
                                eh (this, e);
                }

                protected virtual void OnReadOnlyChanged(EventArgs e) {
                        EventHandler eh = (EventHandler)(Events [ReadOnlyChangedEvent]);
                        if (eh != null)
                                eh (this, e);
                }

                protected override bool ProcessDialogKey(Keys keyData) {
                        return base.ProcessDialogKey(keyData);
                }

                private bool ProcessKey(Keys keyData) {
                        bool control;
                        bool shift;

                        control = (Control.ModifierKeys & Keys.Control) != 0;
                        shift = (Control.ModifierKeys & Keys.Shift) != 0;

                        switch (keyData & Keys.KeyCode) {
                                case Keys.X: {  // Cut (Ctrl-X)
                                        if (control) {
                                                Cut();
                                                return true;
                                        }
                                        return false;
                                }

                                case Keys.C: {  // Copy (Ctrl-C)
                                        if (control) {
                                                Copy();
                                                return true;
                                        }
                                        return false;
                                }

                                case Keys.V: {  // Paste (Ctrl-V)
                                        if (control) {
                                                return Paste(Clipboard.GetDataObject(), null, true);
                                        }
                                        return false;
                                }

                                case Keys.Z: {  // Undo (Ctrl-Z)
                                        if (control) {
                                                Undo();
                                                return true;
                                        }
                                        return false;
                                }

                                case Keys.A: {  // Select All (Ctrl-A)
                                        if (control) {
                                                SelectAll();
                                                return true;
                                        }
                                        return false;
                                }

                                case Keys.Left: {
                                        if (control) {
                                                document.MoveCaret(CaretDirection.WordBack);
                                        } else {
                                                if (!document.selection_visible || shift) {
                                                        document.MoveCaret(CaretDirection.CharBack);
                                                } else {
                                                        document.MoveCaret(CaretDirection.SelectionStart);
                                                }
                                        }

                                        if (!shift) {
                                                document.SetSelectionToCaret(true);
                                        } else {
                                                document.SetSelectionToCaret(false);
                                        }

                                        CaretMoved(this, null);
                                        return true;
                                }

                                case Keys.Right: {
                                        if (control) {
                                                document.MoveCaret(CaretDirection.WordForward);
                                        } else {
                                                if (!document.selection_visible || shift) {
                                                        document.MoveCaret(CaretDirection.CharForward);
                                                } else {
                                                        document.MoveCaret(CaretDirection.SelectionEnd);
                                                }
                                        }
                                        if (!shift) {
                                                document.SetSelectionToCaret(true);
                                        } else {
                                                document.SetSelectionToCaret(false);
                                        }

                                        CaretMoved(this, null);
                                        return true;
                                }

                                case Keys.Up: {
                                        if (control) {
                                                if (document.CaretPosition == 0) {
                                                        document.MoveCaret(CaretDirection.LineUp);
                                                } else {
                                                        document.MoveCaret(CaretDirection.Home);
                                                }
                                        } else {
                                                document.MoveCaret(CaretDirection.LineUp);
                                        }

                                        if ((Control.ModifierKeys & Keys.Shift) == 0) {
                                                document.SetSelectionToCaret(true);
                                        } else {
                                                document.SetSelectionToCaret(false);
                                        }

                                        CaretMoved(this, null);
                                        return true;
                                }

                                case Keys.Down: {
                                        if (control) {
                                                if (document.CaretPosition == document.CaretLine.Text.Length) {
                                                        document.MoveCaret(CaretDirection.LineDown);
                                                } else {
                                                        document.MoveCaret(CaretDirection.End);
                                                }
                                        } else {
                                                document.MoveCaret(CaretDirection.LineDown);
                                        }

                                        if ((Control.ModifierKeys & Keys.Shift) == 0) {
                                                document.SetSelectionToCaret(true);
                                        } else {
                                                document.SetSelectionToCaret(false);
                                        }

                                        CaretMoved(this, null);
                                        return true;
                                }

                                case Keys.Home: {
                                        if ((Control.ModifierKeys & Keys.Control) != 0) {
                                                document.MoveCaret(CaretDirection.CtrlHome);
                                        } else {
                                                document.MoveCaret(CaretDirection.Home);
                                        }

                                        if ((Control.ModifierKeys & Keys.Shift) == 0) {
                                                document.SetSelectionToCaret(true);
                                        } else {
                                                document.SetSelectionToCaret(false);
                                        }

                                        CaretMoved(this, null);
                                        return true;
                                }

                                case Keys.End: {
                                        if ((Control.ModifierKeys & Keys.Control) != 0) {
                                                document.MoveCaret(CaretDirection.CtrlEnd);
                                        } else {
                                                document.MoveCaret(CaretDirection.End);
                                        }

                                        if ((Control.ModifierKeys & Keys.Shift) == 0) {
                                                document.SetSelectionToCaret(true);
                                        } else {
                                                document.SetSelectionToCaret(false);
                                        }

                                        CaretMoved(this, null);
                                        return true;
                                }

                                case Keys.Enter: {
                                        // ignoring accepts_return, fixes bug #76355
                                        if (!read_only && multiline && (accepts_return || (FindForm() != null && FindForm().AcceptButton == null) || ((Control.ModifierKeys & Keys.Control) != 0))) {
                                                Line    line;

                                                if (document.selection_visible) {
                                                        document.ReplaceSelection("", false);
                                                }

                                                line = document.CaretLine;

                                                document.Split(document.CaretLine, document.CaretTag, document.CaretPosition, false);
                                                OnTextChanged(EventArgs.Empty);
                                                document.UpdateView(line, 2, 0);
                                                document.MoveCaret(CaretDirection.CharForward);
                                                document.SetSelectionToCaret(true);
                                                CaretMoved(this, null);
                                                return true;
                                        }
                                        break;
                                }

                                case Keys.Tab: {
                                        if (!read_only && accepts_tab && multiline) {
                                                document.InsertChar(document.CaretLine, document.CaretPosition, '\t');
                                                if (document.selection_visible) {
                                                        document.ReplaceSelection("", false);
                                                }
                                                document.SetSelectionToCaret(true);

                                                OnTextChanged(EventArgs.Empty);
                                                CaretMoved(this, null);
                                                return true;
                                        }
                                        break;
                                }

                                case Keys.Insert: {
                                        if (shift) {
                                                Paste(Clipboard.GetDataObject(), null, true);
                                                return true;
                                        }

                                        if (control) {
                                                Copy();
                                                return true;
                                        }

                                        // FIXME - need overwrite/insert toggle?
                                        return false;
                                }

                                case Keys.PageUp: {
                                        if ((Control.ModifierKeys & Keys.Control) != 0) {
                                                document.MoveCaret(CaretDirection.CtrlPgUp);
                                        } else {
                                                document.MoveCaret(CaretDirection.PgUp);
                                        }
                                        return true;
                                }

                                case Keys.PageDown: {
                                        if ((Control.ModifierKeys & Keys.Control) != 0) {
                                                document.MoveCaret(CaretDirection.CtrlPgDn);
                                        } else {
                                                document.MoveCaret(CaretDirection.PgDn);
                                        }
                                        return true;
                                }

                                case Keys.Delete: {
                                        if (shift) {
                                                Cut();
                                                return true;
                                        }

                                        if (read_only) {
                                                break;
                                        }

                                        if (document.selection_visible) {
                                                document.ReplaceSelection("", false);
                                        } else {
                                                // DeleteChar only deletes on the line, doesn't do the combine
                                                if (document.CaretPosition == document.CaretLine.Text.Length) {
                                                        if (document.CaretLine.LineNo < document.Lines) {
                                                                Line    line;

                                                                line = document.GetLine(document.CaretLine.LineNo + 1);
                                                                document.Combine(document.CaretLine, line);
                                                                document.UpdateView(document.CaretLine, 2, 0);

                                                                #if not_Debug
                                                                Line    check_first;
                                                                Line    check_second;

                                                                check_first = document.GetLine(document.CaretLine.LineNo);
                                                                check_second = document.GetLine(check_first.line_no + 1);

                                                                Console.WriteLine("Post-UpdateView: Y of first line: {0}, second line: {1}", check_first.Y, check_second.Y);
                                                                #endif

                                                                // Caret doesn't move
                                                        }
                                                } else {
                                                        if (!control) {
                                                                document.DeleteChar(document.CaretTag, document.CaretPosition, true);
                                                        } else {
                                                                int end_pos;

                                                                end_pos = document.CaretPosition;

                                                                while ((end_pos < document.CaretLine.Text.Length) && !Document.IsWordSeparator(document.CaretLine.Text[end_pos])) {
                                                                        end_pos++;
                                                                }

                                                                if (end_pos < document.CaretLine.Text.Length) {
                                                                        end_pos++;
                                                                }
                                                                document.DeleteChars(document.CaretTag, document.CaretPosition, end_pos - document.CaretPosition);
                                                        }
                                                }
                                        }

                                        OnTextChanged(EventArgs.Empty);
                                        document.AlignCaret();
                                        document.UpdateCaret();
                                        CaretMoved(this, null);
                                        return true;
                                }
                        }
                        return false;
                }

                private void HandleBackspace(bool control) {
                        bool    fire_changed;

                        fire_changed = false;

                        // delete only deletes on the line, doesn't do the combine
                        if (document.selection_visible) {
                                document.ReplaceSelection("", false);
                                fire_changed = true;
                        }
                        document.SetSelectionToCaret(true);

                        if (document.CaretPosition == 0) {
                                if (document.CaretLine.LineNo > 1) {
                                        Line    line;
                                        int     new_caret_pos;

                                        line = document.GetLine(document.CaretLine.LineNo - 1);
                                        new_caret_pos = line.text.Length;

                                        document.Combine(line, document.CaretLine);
                                        document.UpdateView(line, 1, 0);
                                        document.PositionCaret(line, new_caret_pos);
                                        //document.MoveCaret(CaretDirection.CharForward);
                                        document.UpdateCaret();
                                        fire_changed = true;
                                }
                        } else {
                                if (!control || document.CaretPosition == 0) {
                                        document.DeleteChar(document.CaretTag, document.CaretPosition, false);
                                        document.MoveCaret(CaretDirection.CharBack);
                                } else {
                                        int start_pos;

                                        start_pos = document.CaretPosition - 1;

                                        while ((start_pos > 0) && !Document.IsWordSeparator(document.CaretLine.Text[start_pos - 1])) {
                                                start_pos--;
                                        }
                                        document.DeleteChars(document.CaretTag, start_pos, document.CaretPosition - start_pos);
                                        document.PositionCaret(document.CaretLine, start_pos);
                                }
                                document.UpdateCaret();
                                fire_changed = true;
                        }
                        if (fire_changed) {
                                OnTextChanged(EventArgs.Empty);
                        }
                        CaretMoved(this, null);
                }

                protected override void SetBoundsCore(int x, int y, int width, int height, BoundsSpecified specified) {
                        // Make sure we don't get sized bigger than we want to be
                        if (!richtext) {
                                if (!multiline) {
                                        if (height != PreferredHeight) {
                                                requested_height = height;
                                                height = PreferredHeight;
                                                specified |= BoundsSpecified.Height;
                                        }
                                }
                        }

                        base.SetBoundsCore (x, y, width, height, specified);
                }

                protected override void WndProc(ref Message m) {
                        switch ((Msg)m.Msg) {
                                case Msg.WM_KEYDOWN: {
                                        if (ProcessKeyMessage(ref m) || ProcessKey((Keys)m.WParam.ToInt32() | XplatUI.State.ModifierKeys)) {
                                                m.Result = IntPtr.Zero;
                                                return;
                                        }
                                        DefWndProc (ref m);
                                        return;
                                }

                                case Msg.WM_CHAR: {
                                        int     ch;

                                        if (ProcessKeyMessage(ref m)) {
                                                m.Result = IntPtr.Zero;
                                                return;
                                        }

                                        if (read_only) {
                                                return;
                                        }

                                        m.Result = IntPtr.Zero;

                                        ch = m.WParam.ToInt32();

                                        if (ch == 127) {
                                                HandleBackspace(true);
                                        } else if (ch >= 32) {
                                                if (document.selection_visible) {
                                                        document.ReplaceSelection("", false);
                                                }

                                                char c = (char)m.WParam;
                                                switch (character_casing) {
                                                case CharacterCasing.Upper:
                                                        c = Char.ToUpper((char) m.WParam);
                                                        break;
                                                case CharacterCasing.Lower:
                                                        c = Char.ToLower((char) m.WParam);
                                                        break;
                                                }

                                                if (document.Length < max_length) {
                                                        document.InsertCharAtCaret(c, true);
                                                        OnTextChanged(EventArgs.Empty);
                                                        CaretMoved(this, null);
                                                } else {
                                                        XplatUI.AudibleAlert();
                                                }
                                                return;
                                        } else if (ch == 8) {
                                                HandleBackspace(false);
                                        }

                                        return;
                                }

                                default: {
                                        base.WndProc(ref m);
                                        return;
                                }
                        }
                }

                #endregion      // Protected Instance Methods

                #region Events
                static object AcceptsTabChangedEvent = new object ();
                static object AutoSizeChangedEvent = new object ();
                static object BorderStyleChangedEvent = new object ();
                static object HideSelectionChangedEvent = new object ();
                static object ModifiedChangedEvent = new object ();
                static object MultilineChangedEvent = new object ();
                static object ReadOnlyChangedEvent = new object ();
                static object HScrolledEvent = new object ();
                static object VScrolledEvent = new object ();

                public event EventHandler AcceptsTabChanged {
                        add { Events.AddHandler (AcceptsTabChangedEvent, value); }
                        remove { Events.RemoveHandler (AcceptsTabChangedEvent, value); }
                }

                public event EventHandler AutoSizeChanged {
                        add { Events.AddHandler (AutoSizeChangedEvent, value); }
                        remove { Events.RemoveHandler (AutoSizeChangedEvent, value); }
                }

                public event EventHandler BorderStyleChanged {
                        add { Events.AddHandler (BorderStyleChangedEvent, value); }
                        remove { Events.RemoveHandler (BorderStyleChangedEvent, value); }
                }

                public event EventHandler HideSelectionChanged {
                        add { Events.AddHandler (HideSelectionChangedEvent, value); }
                        remove { Events.RemoveHandler (HideSelectionChangedEvent, value); }
                }

                public event EventHandler ModifiedChanged {
                        add { Events.AddHandler (ModifiedChangedEvent, value); }
                        remove { Events.RemoveHandler (ModifiedChangedEvent, value); }
                }

                public event EventHandler MultilineChanged {
                        add { Events.AddHandler (MultilineChangedEvent, value); }
                        remove { Events.RemoveHandler (MultilineChangedEvent, value); }
                }

                public event EventHandler ReadOnlyChanged {
                        add { Events.AddHandler (ReadOnlyChangedEvent, value); }
                        remove { Events.RemoveHandler (ReadOnlyChangedEvent, value); }
                }

                internal event EventHandler HScrolled {
                        add { Events.AddHandler (HScrolledEvent, value); }
                        remove { Events.RemoveHandler (HScrolledEvent, value); }
                }

                internal event EventHandler VScrolled {
                        add { Events.AddHandler (VScrolledEvent, value); }
                        remove { Events.RemoveHandler (VScrolledEvent, value); }
                }

                [Browsable(false)]
                [EditorBrowsable(EditorBrowsableState.Never)]
                public new event EventHandler BackgroundImageChanged {
                        add { base.BackgroundImageChanged += value; }
                        remove { base.BackgroundImageChanged -= value; }
                }
                [Browsable(false)]
                [EditorBrowsable(EditorBrowsableState.Advanced)]
                public new event EventHandler Click {
                        add { base.Click += value; }
                        remove { base.Click -= value; }
                }

                // XXX should this not manipulate base.Paint?
                [Browsable(false)]
                [EditorBrowsable(EditorBrowsableState.Never)]
                public new event PaintEventHandler Paint;
                #endregion      // Events

                #region Private Methods
                internal Document Document {
                        get {
                                return document;
                        }

                        set {
                                document = value;
                        }
                }

                internal bool ShowSelection {
                        get {
                                if (show_selection) {
                                        return true;
                                }

                                return has_focus;
                        }

                        set {
                                if (show_selection == value)
                                        return;

                                show_selection = value;
                                // Currently InvalidateSelectionArea is commented out so do a full invalidate
                                document.InvalidateSelectionArea();
                        }
                }

                internal Graphics CreateGraphicsInternal() {
                        if (IsHandleCreated) {
                                return base.CreateGraphics();
                        }

                        return Graphics.FromImage(bmp);
                }

                #if Debug
                static int current;
                #endif

                internal override void OnPaintInternal (PaintEventArgs pevent) {
                        // Fill background
                        if (backcolor_set || (Enabled && !read_only)) {
                                pevent.Graphics.FillRectangle(ThemeEngine.Current.ResPool.GetSolidBrush(BackColor), pevent.ClipRectangle);
                        } else {
                                pevent.Graphics.FillRectangle(ThemeEngine.Current.ResPool.GetSolidBrush(ThemeEngine.Current.ColorControl), pevent.ClipRectangle);
                        }
                        pevent.Graphics.TextRenderingHint=TextRenderingHint.AntiAlias;

                        // Draw the viewable document
                        document.Draw(pevent.Graphics, pevent.ClipRectangle);

                        Rectangle       rect = ClientRectangle;
                        rect.Width--;
                        rect.Height--;
                        //pevent.Graphics.DrawRectangle(ThemeEngine.Current.ResPool.GetPen(ThemeEngine.Current.ColorControlDark), rect);

                        #if Debug
                                int             start;
                                int             end;
                                Line            line;
                                int             line_no;
                                Pen             p;

                                p = new Pen(Color.Red, 1);

                                // First, figure out from what line to what line we need to draw
                                start = document.GetLineByPixel(pevent.ClipRectangle.Top - document.ViewPortY, false).line_no;
                                end = document.GetLineByPixel(pevent.ClipRectangle.Bottom - document.ViewPortY, false).line_no;

                                //Console.WriteLine("Starting drawing on line '{0}'", document.GetLine(start));
                                //Console.WriteLine("Ending drawing on line '{0}'", document.GetLine(end));

                                line_no = start;
                                while (line_no <= end) {
                                        line = document.GetLine(line_no);

                                        if (draw_lines) {
                                                for (int i = 0; i < line.text.Length; i++) {
                                                        pevent.Graphics.DrawLine(p, (int)line.widths[i] - document.ViewPortX, line.Y - document.ViewPortY, (int)line.widths[i] - document.ViewPortX, line.Y + line.height  - document.ViewPortY);
                                                }
                                        }

                                        line_no++;
                                }
                        #endif
                }

                internal override void OnGotFocusInternal (EventArgs e)
                {
                        document.CaretHasFocus ();
                        base.OnGotFocusInternal (e);
                }

                internal override void OnLostFocusInternal (EventArgs e)
                {
                        document.CaretLostFocus ();
                        base.OnLostFocusInternal (e);
                }

                private void TextBoxBase_MouseDown(object sender, MouseEventArgs e) {
                        if (e.Button == MouseButtons.Left) {
                                TimeSpan interval;

                                interval = DateTime.Now - click_last;
                                document.PositionCaret(e.X + document.ViewPortX, e.Y + document.ViewPortY);

                                // Handle place caret/select word/select line behaviour
                                if (e.Clicks == 1) {
                                        if (SystemInformation.DoubleClickTime < interval.TotalMilliseconds) {
                                                #if DebugClick
                                                        Console.WriteLine("Single Click Invalidating from char {0} to char {1} ({2})", document.selection_start.pos, document.selection_end.pos, document.selection_start.line.text.ToString(document.selection_start.pos, document.selection_end.pos - document.selection_start.pos));
                                                #endif
                                                document.SetSelectionToCaret(true);
                                                click_mode = CaretSelection.Position;
                                        } else if (this is RichTextBox) {
                                                #if DebugClick
                                                        Console.WriteLine("Tripple Click Selecting line");
                                                #endif
                                                document.ExpandSelection(CaretSelection.Line, false);
                                                click_mode = CaretSelection.Line;
                                        } else {
                                                document.SetSelectionToCaret(true);
                                        }
                                } else {
                                        // We select the line if the word is already selected, and vice versa
                                        if (click_mode != CaretSelection.Word) {
                                                if (click_mode == CaretSelection.Line) {
                                                        document.Invalidate(document.selection_start.line, 0, document.selection_start.line, document.selection_start.line.text.Length);
                                                }
                                                click_mode = CaretSelection.Word;

                                                SelectWord ();
                                        } else if (this is RichTextBox) {
                                                click_mode = CaretSelection.Line;
                                                document.ExpandSelection(CaretSelection.Line, false);   // Setting initial selection
                                        }
                                }

                                // Reset
                                click_last = DateTime.Now;
                                return;
                        }

                        if ((e.Button == MouseButtons.Middle) && (((int)Environment.OSVersion.Platform == 4) || ((int)Environment.OSVersion.Platform == 128))) {
                                Document.Marker marker;

                                marker.tag = document.FindCursor(e.X + document.ViewPortX, e.Y + document.ViewPortY, out marker.pos);
                                marker.line = marker.tag.line;
                                marker.height = marker.tag.height;

                                document.SetSelection(marker.line, marker.pos, marker.line, marker.pos);
                                Paste (Clipboard.GetDataObject (true), null, true);

                        }

                        #if Debug
                                LineTag tag;
                                Line    line;
                                int     pos;

                                if (e.Button == MouseButtons.Right) {
                                        draw_lines = !draw_lines;
                                        this.Invalidate();
                                        Console.WriteLine("SelectedText: {0}, length {1}", this.SelectedText, this.SelectionLength);
                                        Console.WriteLine("Selection start: {0}", this.SelectionStart);

                                        this.SelectionStart = 10;
                                        this.SelectionLength = 5;

                                        return;
                                }

                                tag = document.FindTag(e.X + document.ViewPortX, e.Y + document.ViewPortY, out pos, false);

                                Console.WriteLine("Click found tag {0}, character {1}", tag, pos);
                                line = tag.line;
                                switch(current) {
                                        case 4: LineTag.FormatText(tag.line, pos, (pos+10)<line.Text.Length ? 10 : line.Text.Length - pos+1, new Font("impact", 20, FontStyle.Bold, GraphicsUnit.Pixel), ThemeEngine.Current.ResPool.GetSolidBrush(Color.Red)); break;
                                        case 1: LineTag.FormatText(tag.line, pos, (pos+10)<line.Text.Length ? 10 : line.Text.Length - pos+1, new Font("arial unicode ms", 24, FontStyle.Italic, GraphicsUnit.Pixel), ThemeEngine.Current.ResPool.GetSolidBrush(Color.DarkGoldenrod)); break;
                                        case 2: LineTag.FormatText(tag.line, pos, (pos+10)<line.Text.Length ? 10 : line.Text.Length - pos+1, new Font("arial", 10, FontStyle.Regular, GraphicsUnit.Pixel), ThemeEngine.Current.ResPool.GetSolidBrush(Color.Aquamarine)); break;
                                        case 3: LineTag.FormatText(tag.line, pos, (pos+10)<line.Text.Length ? 10 : line.Text.Length - pos+1, new Font("times roman", 16, FontStyle.Underline, GraphicsUnit.Pixel), ThemeEngine.Current.ResPool.GetSolidBrush(Color.Turquoise)); break;
                                        case 0: LineTag.FormatText(tag.line, pos, (pos+10)<line.Text.Length ? 10 : line.Text.Length - pos+1, new Font("times roman", 64, FontStyle.Italic | FontStyle.Bold, GraphicsUnit.Pixel), ThemeEngine.Current.ResPool.GetSolidBrush(Color.LightSeaGreen)); break;
                                        case 5: LineTag.FormatText(tag.line, pos, (pos+10)<line.Text.Length ? 10 : line.Text.Length - pos+1, ((TextBoxBase)sender).Font, ThemeEngine.Current.ResPool.GetSolidBrush(ForeColor)); break;
                                }
                                current++;
                                if (current==6) {
                                        current=0;
                                }

                                // Update/Recalculate what we see
                                document.UpdateView(line, 0);

                                // Make sure our caret is properly positioned and sized
                                document.AlignCaret();
                        #endif
                }

                private void TextBoxBase_MouseUp(object sender, MouseEventArgs e) {
                        if (e.Button == MouseButtons.Left) {
                                if (click_mode == CaretSelection.Position) {
                                        document.SetSelectionToCaret(false);
                                        document.DisplayCaret();
                                }

                                if (scroll_timer != null) {
                                        scroll_timer.Enabled = false;
                                }
                                return;
                        }
                }

                private void PositionControls ()
                {
                        if (hscroll.Visible) {
                                //vscroll.Maximum += hscroll.Height;
                                canvas_height = ClientSize.Height - hscroll.Height;
                        } else {
                                canvas_height = ClientSize.Height;
                        }

                        if (vscroll.Visible) {
                                //hscroll.Maximum += vscroll.Width;
                                canvas_width = ClientSize.Width - vscroll.Width;
                        } else {
                                canvas_width = ClientSize.Width;
                        }


                        document.ViewPortWidth = canvas_width;
                        document.ViewPortHeight = canvas_height;

                        // We always move them, they just might not be displayed
                        hscroll.Bounds = new Rectangle (ClientRectangle.Left, ClientRectangle.Height - hscroll.Height, ClientSize.Width - (vscroll.Visible ? vscroll.Width : 0), hscroll.Height);
                        vscroll.Bounds = new Rectangle (ClientRectangle.Right - vscroll.Width, ClientRectangle.Top, vscroll.Width, ClientSize.Height - (hscroll.Visible ? hscroll.Height : 0));
                        
                }

                private void TextBoxBase_SizeChanged(object sender, EventArgs e) {
                        CalculateDocument();
                }

                private void TextBoxBase_MouseWheel(object sender, MouseEventArgs e) {
                        Line    line;
                        int     line_no;

                        if (!vscroll.Enabled) {
                                return;
                        }

                        if (e.Delta < 0)
                                vscroll.Value = Math.Min (vscroll.Value + SystemInformation.MouseWheelScrollLines, vscroll.Maximum - document.ViewPortHeight + 1);
                        else
                                vscroll.Value = Math.Max (0, vscroll.Value - SystemInformation.MouseWheelScrollLines);
                }

                internal virtual void SelectWord ()
                {
                        StringBuilder s = document.caret.line.text;
                        int start = document.caret.pos;
                        int end = document.caret.pos;

                        if (s.Length < 1) {
                                if (document.caret.line.line_no >= document.Lines)
                                        return;
                                Line line = document.GetLine (document.caret.line.line_no + 1);
                                document.PositionCaret (line, 0);
                                return;
                        }

                        if (start > 0) {
                                start--;
                                end--;
                        }

                        // skip whitespace until we hit a word
                        while (start > 0 && s [start] == ' ')
                                start--;
                        if (start > 0) {
                                while (start > 0 && (s [start] != ' '))
                                        start--;
                                if (s [start] == ' ')
                                        start++;
                        }

                        if (s [end] == ' ') {
                                while (end < s.Length && s [end] == ' ')
                                        end++;
                        } else {
                                while (end < s.Length && s [end] != ' ')
                                        end++;
                                while (end < s.Length && s [end] == ' ')
                                        end++;
                        }

                        document.SetSelection (document.caret.line, start, document.caret.line, end);
                }

                internal void CalculateDocument() {
                        if (!IsHandleCreated) {
                                return;
                        }
                        document.RecalculateDocument(CreateGraphicsInternal());
                        CalculateScrollBars();
                        Invalidate();
                }

                internal void CalculateScrollBars () {
                        // FIXME - need separate calculations for center and right alignment

                        if (!multiline) {
                                PositionControls ();
                                return;
                        }

                        if (document.Width >= document.ViewPortWidth) {
                                hscroll.SetValues (0, Math.Max (1, document.Width), -1,
                                                document.ViewPortWidth < 0 ? 0 : document.ViewPortWidth);
                                hscroll.Enabled = true;
                        } else {
                                hscroll.Enabled = false;
                                hscroll.Maximum = document.ViewPortWidth;
                        }

                        if (document.Height >= document.ViewPortHeight) {
                                vscroll.SetValues (0, Math.Max (1, document.Height), -1,
                                                document.ViewPortHeight < 0 ? 0 : document.ViewPortHeight);
                                vscroll.Enabled = true;
                        } else {
                                vscroll.Enabled = false;
                                vscroll.Maximum = document.ViewPortHeight;
                        }


                        if (!WordWrap) {
                                if ((scrollbars & RichTextBoxScrollBars.Horizontal) != 0) {
                                        if (((scrollbars & RichTextBoxScrollBars.ForcedHorizontal) != 0) || hscroll.Enabled) {
                                                hscroll.Visible = true;
                                        } else {
                                                hscroll.Visible = false;
                                        }
                                } else {
                                        hscroll.Visible = false;
                                }
                        }

                        if ((scrollbars & RichTextBoxScrollBars.Vertical) != 0) {
                                if (((scrollbars & RichTextBoxScrollBars.ForcedVertical) != 0) || vscroll.Enabled) {
                                        vscroll.Visible = true;
                                } else {
                                        vscroll.Visible = false;
                                }
                        } else {
                                vscroll.Visible = false;
                        }

                        PositionControls ();
                }

                private void document_WidthChanged(object sender, EventArgs e) {
                        CalculateScrollBars();
                }

                private void document_HeightChanged(object sender, EventArgs e) {
                        CalculateScrollBars();
                }

                private void hscroll_ValueChanged(object sender, EventArgs e) {
                        int old_viewport_x;

                        old_viewport_x = document.ViewPortX;
                        document.ViewPortX = this.hscroll.Value;

                        if (vscroll.Visible) {
                                XplatUI.ScrollWindow(this.Handle, new Rectangle(0, 0, ClientSize.Width - vscroll.Width, ClientSize.Height), old_viewport_x - this.hscroll.Value, 0, false);
                        } else {
                                XplatUI.ScrollWindow(this.Handle, ClientRectangle, old_viewport_x - this.hscroll.Value, 0, false);
                        }
                        document.UpdateCaret();

                        EventHandler eh = (EventHandler)(Events [HScrolledEvent]);
                        if (eh != null)
                                eh (this, EventArgs.Empty);
                }

                private void vscroll_ValueChanged(object sender, EventArgs e) {
                        int old_viewport_y;

                        old_viewport_y = document.ViewPortY;
                        document.ViewPortY = this.vscroll.Value;

                        if (hscroll.Visible) {
                                XplatUI.ScrollWindow(this.Handle, new Rectangle(0, 0, ClientSize.Width, ClientSize.Height - hscroll.Height), 0, old_viewport_y - this.vscroll.Value, false);
                        } else {
                                XplatUI.ScrollWindow(this.Handle, ClientRectangle, 0, old_viewport_y - this.vscroll.Value, false);
                        }
                        document.UpdateCaret();

                        EventHandler eh = (EventHandler)(Events [VScrolledEvent]);
                        if (eh != null)
                                eh (this, EventArgs.Empty);
                }

                private void TextBoxBase_MouseMove(object sender, MouseEventArgs e) {
                        // FIXME - handle auto-scrolling if mouse is to the right/left of the window
                        if (Capture) {
                                if (!ClientRectangle.Contains (e.X, e.Y)) {
                                        if (scroll_timer == null) {
                                                scroll_timer = new Timer ();
                                                scroll_timer.Interval = 100;
                                                scroll_timer.Tick += new EventHandler (ScrollTimerTickHandler);
                                        }

                                        if (!scroll_timer.Enabled) {
                                                scroll_timer.Start ();

                                                // Force the first tick
                                                ScrollTimerTickHandler (null, EventArgs.Empty);
                                        }

                                        return;
                                }

                                document.PositionCaret(e.X + document.ViewPortX, e.Y + document.ViewPortY);
                                if (click_mode == CaretSelection.Position) {
                                        document.SetSelectionToCaret(false);
                                        document.DisplayCaret();
                                }
                        }
                }
                                                                              
                private void TextBoxBase_FontOrColorChanged(object sender, EventArgs e) {
                        if (!richtext) {
                                Line    line;

                                // Font changes apply to the whole document
                                for (int i = 1; i <= document.Lines; i++) {
                                        line = document.GetLine(i);
                                        LineTag.FormatText(line, 1, line.text.Length, Font, ThemeEngine.Current.ResPool.GetSolidBrush(ForeColor));
                                        document.UpdateView(line, 0);
                                }
                                // Make sure the caret height is matching the new font height
                                document.AlignCaret();
                        }
                }

                private void ScrollTimerTickHandler (object sender, EventArgs e)
                {
                        Point pt = Cursor.Position;

                        pt = PointToClient (pt);

                        if (pt.X < ClientRectangle.Left) {
                                document.MoveCaret(CaretDirection.CharBackNoWrap);
                                document.SetSelectionToCaret(false);
                                
                                CaretMoved(this, null);
                        } else if (pt.X > ClientRectangle.Right) {
                                document.MoveCaret(CaretDirection.CharForwardNoWrap);
                                document.SetSelectionToCaret(false);
                                
                                CaretMoved(this, null);
                        } else if (pt.Y > ClientRectangle.Bottom) {
                                document.MoveCaret(CaretDirection.LineDown);
                                document.SetSelectionToCaret(false);
                                
                                CaretMoved(this, null);
                        } else if (pt.Y < ClientRectangle.Top) {
                                document.MoveCaret(CaretDirection.LineUp);
                                document.SetSelectionToCaret(false);
                                
                                CaretMoved(this, null);
                        }
                }

                /// <summary>Ensure the caret is always visible</summary>
                internal void CaretMoved(object sender, EventArgs e) {
                        Point   pos;
                        int     height;
                        
                        pos = document.Caret;
                        //Console.WriteLine("Caret now at {0} (Thumb: {1}x{2}, Canvas: {3}x{4}, Document {5}x{6})", pos, hscroll.Value, vscroll.Value, canvas_width, canvas_height, document.Width, document.Height);


                        // Horizontal scrolling:
                        // If the caret moves to the left outside the visible area, we jump the document into view, not just one
                        // character, but 1/3 of the width of the document
                        // If the caret moves to the right outside the visible area, we scroll just enough to keep the caret visible

                        // Handle horizontal scrolling
                        if (document.CaretLine.alignment == HorizontalAlignment.Left) {
                                // Check if we moved out of view to the left
                                if (pos.X < (document.ViewPortX)) {
                                        do {
                                                if ((hscroll.Value - document.ViewPortWidth / 3) >= hscroll.Minimum) {
                                                        hscroll.Value -= document.ViewPortWidth / 3;
                                                } else {
                                                        hscroll.Value = hscroll.Minimum;
                                                }
                                        } while (hscroll.Value > pos.X);
                                }

                                // Check if we moved out of view to the right
                                if ((pos.X >= (document.ViewPortWidth + document.ViewPortX)) && (hscroll.Value != hscroll.Maximum)) {
                                        if ((pos.X - document.ViewPortWidth + 1) <= hscroll.Maximum) {
                                                if (pos.X - document.ViewPortWidth >= 0) {
                                                        hscroll.Value = pos.X - document.ViewPortWidth + 1;
                                                } else {
                                                        hscroll.Value = 0;
                                                }
                                        } else {
                                                hscroll.Value = hscroll.Maximum;
                                        }
                                }
                        } else if (document.CaretLine.alignment == HorizontalAlignment.Right) {
//                              hscroll.Value = pos.X;

//                              if ((pos.X > (this.canvas_width + document.ViewPortX)) && (hscroll.Enabled && (hscroll.Value != hscroll.Maximum))) {
//                                      hscroll.Value = hscroll.Maximum;
//                              }
                        } else {
                                // FIXME - implement center cursor alignment
                        }

                        if (!multiline) {
                                return;
                        }

                        // Handle vertical scrolling
                        height = document.CaretLine.Height + 1;

                        if (pos.Y < document.ViewPortY) {
                                vscroll.Value = pos.Y;
                        }

                        if ((pos.Y + height) > (document.ViewPortY + canvas_height)) {
                                vscroll.Value = pos.Y - canvas_height + height;
                        }
                }

                internal bool Paste(IDataObject clip, DataFormats.Format format, bool obey_length) {
                        string          s;

                        if (clip == null)
                                return false;
                        
                        if (format == null) {
                                if ((this is RichTextBox) && clip.GetDataPresent(DataFormats.Rtf)) {
                                        format = DataFormats.GetFormat(DataFormats.Rtf);
                                } else if (clip.GetDataPresent(DataFormats.UnicodeText)) {
                                        format = DataFormats.GetFormat(DataFormats.UnicodeText);
                                } else if (clip.GetDataPresent(DataFormats.Text)) {
                                        format = DataFormats.GetFormat(DataFormats.Text);
                                } else {
                                        return false;
                                }
                        } else {
                                if ((format.Name == DataFormats.Rtf) && !(this is RichTextBox)) {
                                        return false;
                                }

                                if (!clip.GetDataPresent(format.Name)) {
                                        return false;
                                }
                        }

                        if (format.Name == DataFormats.Rtf) {
                                ((RichTextBox)this).SelectedRtf = (string)clip.GetData(DataFormats.Rtf);
                                return true;
                        } else if (format.Name == DataFormats.UnicodeText) {
                                s = (string)clip.GetData(DataFormats.UnicodeText);
                        } else if (format.Name == DataFormats.Text) {
                                s = (string)clip.GetData(DataFormats.Text);
                        } else {
                                return false;
                        }

                        if (!obey_length) {
                                this.SelectedText = s;
                        } else {
                                if ((s.Length + document.Length) < max_length) {
                                        this.SelectedText = s;
                                } else if (document.Length < max_length) {
                                        this.SelectedText = s.Substring(0, max_length - document.Length);
                                }
                        }

                        return true;
                }
                #endregion      // Private Methods
        }
}